NUT TREE GROWING IN KENTUCKY "NUT TREE GROWING IN KENTUCKY" (ID-77)  (Publication in progress - Updated 3/09/2006)

J. G. Strang, R. T. Jones, Extension Horticulturists; R. Bessin, Extension Entomologist; and J. R. Hartman, Extension Plant Pathologist* University of Kentucky College of Agriculture

            Kentucky is generally well-suited for growing nut trees.  Northern pecans, black walnuts, heartnuts, hickory nuts, hardy Persian walnuts (Carpathian), American hazelnuts, and Chinese chestnuts all grow well in the state.  Most nut trees are grown by hobbyists and backyard gardeners.  Several varieties appear to have potential for commercial production, particularly some of the USDA pecan selections and some Chinese chestnut varieties.  Nut trees grow best in deep, well-drained soil of medium to good fertility with a soil pH of 6.5-6.8.  Chinese chestnuts grow best on acidic soils.

            Pecan growing in Kentucky should be limited to "Northern" varieties because Kentucky's growing season is usually not long enough for southern pecans to mature, i.e. for kernels to fill the shell.  Nuts of Northern pecan varieties will not mature at higher elevations where day and night summer temperatures vary greatly.  However, trees do grow well on these sites and make excellent shade trees.

            If nuts of a particular variety are planted they will not produce a tree of that variety.  Rather, to get a tree of a certain variety, wood from that variety must be grafted onto a rootstock.

            All nut trees except filberts become quite large.  Since nut trees take many years to fill their allotted space, some growers plant filler trees and remove them later, before branches of adjoining trees meet.  The following chart shows suggested minimum permanent spacings and average years to first harvest when grafted trees are set out.

*The authors wish to thank Leslie Wilmoth, John Brittain, Roby Kight, Ed Canty, Fred Blankenship, and the late W. C. Donoho and Henry Converse for their extensive help in preparing this publication.

PLANTING, FERTILIZATION AND PRUNING

Planting Seed 

            Nut seeds are generally planted about 2 inches deep, soon after harvest in the fall.  They do not germinate until late spring.  The "Tin Can" planting system helps reduce losses to mice, squirrels and other wildlife that may eat them.  To use this technique remove the top of a tin can and with a knife make two cuts across the bottom, crossing in the center.  Push the empty can into the soil over the planted nut until the cut end is flush with the soil surface.  In early spring slightly turn up the metal tips at the center of the can so that the seedling can grow through the opening but pests still cannot get it. As the seedling grows, turn the tips back further.

            There is no need to remove the tin can, because it usually rusts out, particularly if it has been burned to remove the galvanized coating.  However, an aluminum can does not rust and must be cut down one side to permit easy removal before it girdles the young tree.

            When planting nuts where the tree is to mature, plant 3 nuts.  Position them in a triangular pattern spaced about 1 foot apart and 2 inches deep.  One or two years later, graft or bud the largest of the 3 seedlings to the desired variety and remove the other two.  Exceptions: Chinese chestnuts are not difficult to graft, but rootstock incompatibility may be a problem if the cultivar being grafted is not placed onto a seedling originating from this cultivar.  Hardy American or Eastern filberts are difficult to graft and in the past have been propagated by seed.  New blight resistant varieties have been and will continue to be developed that can be purchased.  If propagation is not feasible, grafted or budded nursery stock is recommended.

Planting Trees

●  Early spring planting of nursery nut trees is better than fall planting, because it reduces the chance of winter injury.

●  Plant trees as soon as possible after receipt.

●  Do not let roots dry out.  Tree survival may often be improved by soaking the tree roots in water for 24 hours before planting.

●  Prune off broken roots and shorten long ones before planting.

●  Dig a deep hole, wide enough so that lateral roots can spread out in their natural positions and deep enough so the tap root (if there is one) will not bend.

●  Leave the tap root as long as possible, preferably not less than 24 inches to improve survival.  Trees should be planted as deep as they were in the nursery.  Examine tree trunks to find the soil line.

●  Set the tree in the hole and fill with soil.  If the soil is not too wet, firm the soil around the roots with the hands.

●  Water trees well following planting to settle the soil around the roots, and then weekly throughout the summer during dry conditions.  Watering trees during the first season is extremely important in establishment.

● Backfill around all planted trees with loose soil after rains have settled the soil in the planting holes.

Fertilizing 

            Take a soil test, and, based on its results, adjust soil fertility at least a month before planting.  Adjust the pH to 6.5 and bring phosphorus and potassium levels into the high soil test range.  Do not fertilize at planting, since doing so can injure roots.

            After the first year, follow this procedure for fertilization: (1) Determine the trunk diameter 5 inches above ground. (2) For each inch of trunk diameter, apply 1 lb of 10-10-10 fertilizer, but no more than 1/3 lb of actual nitrogen per inch of trunk diameter  per season. (3) Place fertilizer under the tree periphery in late February. (4) Take soil tests annually and apply lime as needed to prevent soil pH from falling below 6.0.

            Trace elements are very important in nut production.  Zinc is the most critical trace element.  When zinc is lacking or present in insufficient quantities, nutlets fail to set and yields are very low.  Zinc is best applied as a foliar spray just after pollination at a rate of 1 to 2 lb of zinc sulfate/100 gal of water (1 to 2 Tbsp./gal).  Apply twice more at 2 to 3 week intervals.

Pruning

            Remove about 1/3 of the top growth at planting.  Cut the terminal shoot  just above a bud and remove all side branches close to the trunk.  This encourages survival and strong regrowth.  Prune young trees lightly during the first few years in February or March to select scaffold limbs with wide crotch angles and to maintain a central leader.  Branches should be pruned off the trunk to a height of at least 6 ft if you plan to use a metal tree guard to control squirrels. When 10-15 good scaffold limbs that are well-spaced on the trunk have been developed, cut the central leader back to a lateral limb, and train the tree to a modified central leader shape.  For more detailed explanations of pruning, see Cooperative Extension publication HO-64, Growing Fruit at Home in Kentucky.  Only limited pruning is needed on bearing trees.  Remove dead limbs to a side limb or to the trunk to promote rapid healing and avoid trunk decay.  When trees are 20 to 30 years old, thin out some of the top scaffold limbs to allow light into the interior of the trees.

            American hazelnuts are grown as a bush and pruning consists of thinning out smaller, weaker shoots by removing them at ground level.  Also, remove some of the center shoots to admit light and avoid bearing only on the bush periphery.  A plant should have 5-7 main shoots.  Grafted hazelnuts are grown as a tree and all suckers need to be removed from the base.

SUNSCALD AND RODENT PROTECTION

Sunscald Protection

            Young trees are particularly susceptible to sunscald injury.  On bright cold sunny days during winter the bark on the southwest side of the trunk and on top of northeast growing limbs may warm up considerably.  A rapid drop in temperature when the sun passes behind a cloud or a hill or when it goes down in the evening often causes vertical splits in the bark and separates bark from the trunk.  Large dead areas on the trunk usually result from this type of injury.

            Sunscald may be prevented by painting the lower 30 to 36 inches of trunk and the bases of some scaffold limbs with an interior white latex paint in the fall, by using a white plastic rodent guard or by wrapping the trunk with aluminum foil.  These actions prevent the southwest side of the tree trunk from heating up and help to eliminate this type of injury.

Rodent Protection

            If a white plastic rodent guard is not used around the trunk following planting, place a loose cylinder of 1/4 inch hardware cloth at least 18 inches high, around the trunk.  This will keep rabbits from damaging or killing young trees.  Remove mulch from the base of the trees in the fall to prevent vole damage.

IRRIGATION, MULCHING AND WEED CONTROL

            Inadequate weed control and lack of water are the two primary reasons for poor nut tree growth, particularly in the first season.  Even mowed grass competes heavily with young trees for nutrients and water. Maintain a vegetation-free area beneath the trees to reduce competition from grass and weeds.  This area should be from 4 to 6 ft in diameter and expanded as the trees get older.   Mulching with wood chips, bark, hay or straw is very beneficial.  Mulch should be kept at least six inches away from the tree base to avoid injury from mulch heating and to help reduce rodent damage.

            During the growing season when soil is dry, irrigation helps promote tree growth and reduce stress, especially in the first year. On bearing trees, irrigation will help produce larger nuts and improve nut fill. Generally, if water is scarce before nut shells form, nut size will be reduced.  Lack of water after shell hardening inhibits kernel filling.

POLLINATION

            Pollen of pecan, black walnut, butternut, Persian walnut, heartnut, hickory, filbert, and hican, is airborne.  It is carried by wind, not insects.  While Chinese chestnut pollen is air-borne, some may also be carried by insects.  Since nut trees depend on wind and gravity to disperse pollen, prolonged rainy periods during pollen shed remove pollen from the air and may substantially reduce the nut set.

            Nut trees have both male and female flowers, located on different parts of the same branch.  Male flowers are catkins, which are on one year old branches.  Female or nutlet flowers resemble miniature nuts and are situated at the ends of young shoot tips.  The stigma is at the tip of the female flower and is receptive when it become glossy with stigmatal fluid.  Pollination takes place when pollen falls on the stigma.  Most nut cultivars and seedling trees are largely self-sterile because the pollen is not ripe and is not shed from catkins when female flowers are receptive.  A variety may be either protogynous or protandrous.  Protogynous - pistallate (female) flowers are receptive before pollen is shed from catkins (male).  Protandrous - pollen is shed from catkins (male) before pistallate (female) flowers are receptive.

            Important -- A mixture of varieties that shed pollen early and late is required for good pollination.  However, a mixture of varieties will not automatically assure a steady, season-long pollen supply.  Most nut trees, seedlings or grafted trees, require medium to late, some very late pollen.  Most nut trees shed pollen early--a lot shed very early.  In seasons when large quantities of pollen are shed some reports indicate that pollen has been carried by wind as far as one mile and has effectively pollinated pecan trees.

            Pecans are mostly self-unfruitful, so it is very important to buy or propagate special pollinator trees to successfully set a full crop of nuts.  Pecan pollinator cultivars or selections are listed in Table 1.  The pollen of 'Posey' is shed late and will pollinate female flowers of 'Major' which become receptive late (see Table 1 on Pecan Blooming Periods for more information).  Seedlings or native pecan trees can also be used for pollination, if they bloom at the right time.  A mixture of varieties assures a steady, season-long pollen supply.

           Black walnut varieties are considered self-fruitful, although they perform much better when cross-pollinated.

            Butternuts, like black walnuts, are self-fruitful, but will yield better when cross-pollinated.  They also pollinate heartnuts and are pollinated by heartnuts.  They do not cross easily with black walnuts.

            Persian walnuts may be either self-fruitful or partially self-fruitful.  In the latter case, pollination and nut set, are greatly improved by cross pollination with another cultivar or seedling.   Please note cultivar pollination requirements in the cultivar descriptions.

            Chinese chestnuts are very self-sterile and require other Chinese chestnut trees within 50 to 100 ft. An unpollinated tree will produce burrs, but most will be empty inside.  Individual limbs may be grafted to other varieties to provide pollination.

            Hazelnuts or filberts are self-sterile and varieties may be either protogynous or protandrous.

            Heartnuts are self-fruitful, but do better when cross-pollinated.

            Hicans are generally self-sterile.  If they are self-sterile, they need to be pollinated by an early shedding pecan such as 'Major.'

            Hickory nuts may be self-fruitful in some cases, but allowing for cross-pollination is better.

CULTIVAR RECOMMENDATIONS FOR KENTUCKY

            Many of the cultivars listed in this publication can be purchased through Kentucky nut tree nurseries.  If extensive nut tree plantings are planned or new cultivars are desired individuals may wish to contact the Kentucky Nut Growers Association.  Your local county extension office can help you locate Kentucky nut tree nurseries and put you in contact with the Kentucky Nut Growers Association.

Black Walnuts Juglans nigra  

            Black walnuts begin growth late in the spring and there is generally little problem with injury and crop loss from late spring freezes.  Problems with black walnuts generally relate to poor cracking qualities, disease and alternate bearing.  The number of nuts per pound is related to the cultivar planted.  Light crops produce larger nuts, while full or bumper crops produce smaller nuts.

            Clermont - Medium-size nut, with a thin shell.  The kernel has an excellent flavor.  The tree has excellent bearing characteristics and resistance to anthracnose disease.

            Daniels - This is a productive variety producing nuts with a kernel percentage of 41%.  This is a relatively small nut, running about 32 nuts per pound.  The shell is very thin, making this an easy variety to crack.

            Emma Kay - Produces a medium to large, thin-shelled nut that cracks out well.  Nuts will average 25 to 30 per pound.      

            Hare - A productive cultivar with a medium-size nut of excellent quality.  The nut is somewhat susceptable to husk maggots.

            Hay Seedling - Large nut, looks like Thomas-Myers, found by Leander Hay.

            Krause - A very productive cultivar.  Nut is almost identical to Daniels, but has a better shell structure.

            Myers (Elmer Myers) - Nut size is medium.  The shell is thin and nut meats are easy to extract.

            Neal #1 - Thin shell, high crack out, kernel shaped like a human heart, star at base of nut, slow to come into bearing. Excellent nut, one of the best.

            Pounds- 2 - This is one of the most exciting new varieties.  Leon Pounds-2 is a very productive thin shelled nice tasting black walnut.  It has the highest highest crack out percentage of any variety, 55%.  This is a second generation Thomas or a seedling of a seedling and is thought to be crossed with Elmer Myers.  It was found by the late Leon Pounds of Gentryville, IN.

            Rabbit Ridge or Ridgeway - Nuts from the original tree have placed first in the nut competition at the Kentucky State Fair.  This selection has not been extensively planted and fruited in Kentucky.

            Schrieber - Trees of this variety produce the largest nuts of any currently being evaluated, with about 15-20 per pound.  It is similar to the Thomas-Meyers variety; however, the kernel percentage is lower, but still a respectable 25%.  The nut has excellent cracking qualities and a very good tasting kernel.

            Sparrow - Nut is medium in size running 25-30 per pound, with good cracking quality.  The kernel is sweet and of good quality.  The tree is hardy and tends to retain its foliage later than most other varieties.  All nuts fall off the tree at about the same time and they hull easily.

            Thomas-Myers - Produces a large outstanding nut which averages 17-24 nuts per pound.  Kernel percentages average 35 to 40 percent.  The tree is an annual bearer and begins growth late in the spring, almost two weeks later than other cultivars. Consequently it is one of the least frost prone black walnut cultivars.  Nuts mature in late October and as a result this cultivar is not recommended for latitudes north of Indianapolis or Omaha.  This is one of the best black walnut cultivars for Kentucky.

     Other black walnut cultivars reported to have superior characteristics and now being offered in the nursery trade are:

Beck    Football 2        Harney            Neal #1            Rowher           Surprise

Thomas is very susceptible to anthracnose disease, alternate bears and nuts do not fill.  Consequently, 'Thomas' is not recommended for Kentucky.

Butternuts Juglans cinerea

            Butternuts are not generally recommended in Kentucky except in the mountains at high elevations.  Because they are susceptible to bacterial canker in most areas, they tend to be short-lived, rarely surviving more than 20 years.  Trees are hardier than most walnuts and nuts have a unique flavor similar to that of walnuts.  The shells are thick and contain only a small amount of meat.

            Varieties suggested on good sites are:

Ayers              Beckwith         Buckley           Chamberlin      Coble #1

Craxezy          Creighton        Morehead #1   My Joy            Weschcke

Hardy Persian (English) Walnuts Juglans regia  

            One of the greatest problems with Persian walnuts is that they begin growth fairly early in the spring and the flowers are damaged by late spring frosts.  Varieties that bear nuts laterally as opposed to just terminally tend to produce better in frost years. Poor shell structure is a problem with some varieties where the shell seam does not completely seal allowing mildew to attack the kernel.

            The male flowers, (catkins) begin development long before the female nutlet flowers and are consequently often killed by late spring frosts.  The Lake variety has more hardy, slower developing catkins and survives late spring frosts more often.  This variety should always be planted with most other cultivars which fail to produce pollen in most years.  The following varieties are generally recommended.

            Allegheny - A new variety from Pennsylvania, which vegetates late, misses frost and can bear a full crop annually, even after -28̊ F winters.  The tree is self pollinating and produces a medium sized nut with a thin shell that has a tight seal and cracks out in whole halves.  A recent Pennsylvania State Fair blue ribbon winner.

            Bedco 1 - Medium to large nut, sweet light kernel, very productive.

            Broadview - One of the heaviest bearing varieties.  Medium to large nut has a thin shell.  Kernels are best for culinary purposes.  This is a good parent tree for breeding purposes.  Broadview seedlings produced from cross-pollination with 'Hansen' have resulted in some superior cultivars. Lateral bearing.

            Colby - Medium size nut has a thin shell.  It is early maturing, hardy, with a plump kernel and good

 flavor.  It has self-fruitful flowers.  Protandrous.

            Coble #2 - Well filled large high quality nut. Lateral bearing

            Greenhaven - Nut is medium to large, and early maturing.  Nuts begin to drop about September first.  The nuts fill well and have well-sealed shells.  This is one of the better cultivars.

            Hansen - Nut is small to medium, round, has a thin shell and good taste.  The tree is very productive, self-fruitful, hardy and resistant to anthracnose and husk maggot.

            Kaiser - Nut has outstanding qualities and is one of the largest.  This is a beautiful large nut that fills very well, seals good and tasted good. The tree also begins production at a young age. Kaiser was rated as the most outstanding Persian walnut at the 2000 Kentucky State Fair.  This variety originated from a seedling grown by Richard Wilmoth in Kentucky.

            Kentucky Giant - Very large, good tasting nut.  The kernel is light in color, but does not always completely fill the shell.  The tree is not as winter hardy as some varieties and needs to be well-pollinated.  It bears well when it has a crop.

            Lake - Nut is medium to large in size, very good quality and hardy.  The nut shell has very tight seams and the nut fills completely with an excellent kernel.  It produces a few nuts even in very bad frost years and is highly recommended for Kentucky.  This is an important pollinator for most other varieties.

            Reda - Nut medium size, thin shell, bears on lateral buds. The tree is hardy.

            Sauber Giant - Produces a very large nut that is similar to Kentucky Giant, fills well and is of good quality.  The tree is very hardy and bears early.  However, the tree begins growth early, is sensitive to frost and is recommended only on sites where frost is less of a problem.

            Somers - Large nut, cracks easy, 55% kernel. Annual bearing and early maturing.

            Utah Giant - Very large good quality nut with a sweet kernel. Very hardy

            Other new introductions reported to have superior characteristics are:

Cascade         Fately              McKinister

Chinese Chestnuts Castanea mollissima

             The survival rate of grafted chestnut trees, particularly of American X Chinese hybrids has been less than ideal due to incompatibility between the scion and rootstock. However, by grafting the desired cultivar onto seedlings from this same cultivar, losses from incompatibility can be almost entirely eliminated.  All of the following recommended cultivars are chestnut blight resistant.

            Armstrong - This medium to large nut is one of the best tasting, but it doesn't keep long in storage.  The tree bears very well. Chinese X American hybrid.

            AU Leader - Very sweet large nut. Excellent flavor raw or roasted. Auburn University release.

            Bright - Has a large nut with a very sweet high quality kernel with an excellent taste.  This is an outstanding selection and is highly recommended.

            Crane - This medium to large nut runs about 25-30 nuts per pound.  Crane is of good quality and has keeping characteristics that are superior to all other varieties.  Tree bears well and is a precocious producer.  Chinese

            Eaton River - One of the sweetest Chinese chestnuts.  It bears in early September and produces heavy crops of large nuts (30-40/lb). 

            Ford’s Sweet - A heavy bearing timber-type Chinese chestnut that has a sweet kernel like the American Chestnut.  Nuts are small and make good wildlife food.

            Ford’s Tall - A timber-type Chinese chestnut similar to Ford’s Sweet that reaches a height of 70 feet.  Medium sized nuts.

            Mossbarger - A good, large (28-32/lb), very sweet nut that keeps better than most varieties.  This Chinese chestnut tree is productive and an annual bearer.    

            Qing - Produces two to four mahogany colored nuts per burr with few singles, 90 percent fall free from burs. Nuts are large, some the size of a half dollar (18-22/lb), very sweet, well filled with a yellow meat. Pellicle (skin around the meat) separates freely from the nut. Good both raw or roasted and stores very well. A Chinese selection that is a heavy producer and considered one of the best cultivars.

            Sleeping Giant - Produces a large (30-35/lb), sweet, attractive light tan colored nut, making it a good market chestnut.  Chinese X Japanese X American hybrid.

            Additional cultivars now becoming available in the nursery trade are Henry VIII, Wolverine and many others.  Seedling chestnut trees may be planted, but only about 25% will bear nuts of acceptable quality.

American Hazelnuts or filberts Corylus americana 

            Native American hazelnuts and the European hazelnuts, Corylus avellana are both plagued by Eastern filbert blight (EFB), which is a fungus disease that eventually kills most hazelnuts grown in Kentucky.  The European hazelnut is the species that is generally grown for nut production in Oregon and ‘Barcelona’ has been the primary variety grown in the past.  Eastern filbert blight has become a serious problem in the pacific northwest and Oregon State University has released several cultivars, Santiam with complete resistance to EFB and Willamette, Lewis and Clark with improved resistance to EFB.  Hazelnuts bloom in the winter and the European hazelnuts often have their flowers killed during the winter in Kentucky.

            In other areas breeders have been working to develop hazelnut hybrids that are hardier than the European hazelnut and have resistance to EFB.  Hybrid hazelnut cultivar releases that have EFB resistance include: Grand Traverse, 89-Lisa, G-22, 88-BS, G-14, G-17 by Cecil Farris, Lansing, MI; Rush and Winkler from Lancaster, PA; Carlola, Delores, Magdalene by Carl Weschcke, MN; and Laroka, Eastoka, Faroka, and Morrisoka by J. U. Gellatly, Westbank, BC.  None of these have been evaluated in Kentucky.

Heartnuts Juglans cordiformis

            A common problem with all heartnuts is that they are subject to blossom loss from late spring frosts.  However, their foliage is very attractive and they make good landscape trees.  Bunch disease can be a problem and it is best not to plant heartnuts near black walnut trees.

            Canoka - Large nut and the tree bears heavily.  The tree begins growth later than most other varieties and is less susceptible to frost injury.

            Frank - This is a seedling selection named after the late Frank Street of Henderson, Kentucky.  It is an outstanding selection which produces a crop almost every year despite late spring frosts.  It produces an attractive nut with an excellent kernel.  This cultivar is highly recommended.

            Jewel Box - Productive tree with a very large nut that cracks well. Tree begins growth early in the spring and is more prone to late spring frosts.

            Marvel - Medium to large nut that cracks well and is of good quality.  The tree bears heavily and is hardier than 'Fodermaier,' but the tree begins growth early in the spring.

            Mitchell Hybrid - A butternut X heartnut hybrid that is very productive had has heartnut shaped nuts. Vegetates early.

            Rhodes - Begins growth later in the spring and is more resistant to frost than many other varieties.

Hicans

            Hicans are crosses between pecans and shellbark, shagbark, or bitternut hickories.  These hybrids often have mature nuts earlier than pecans and consequently do well in northern areas.  Unfortunately, most cultivars are rather poor producers.

            Burton - Produces a good quality nut with a thin shell.  The cultivar is self-fertile and originated on a farm south of Owensboro, KY.  Pecan X shagbark.

            Additional cultivars that do well in Kentucky are:

Bixby                           Burlington                    Country Club               Dooley Burton Hartmann       

Henke                         Hershy                        Jackson                      Johnson                      L3                   

McAllister                    Palmer             T-92

Shagbark Hickories Carya ovata  

            Cook Shag - Oval flat nut that cracks out in halves, good flavor, from Kentucky.

            Grainger - Large nut with a large flat kernel, from Grainger county Tennessee.

            Raudabaugh - Thin shell, cracks out well, seedling from Pennsylvania.

            Yoder #1 - A regular heavy producer of good-flavored, average sized nuts.

            Wilmoth - A thin shelled nut with a large, light colored, good tasting kernel.

            Additional recommended varieties include:

Abundance                  Bridgewater                 Cody Cox                    Etter                            Sauber

Seas                            Silvis 303                    Walters                        Wilcox                         Wurth

Shellbark Hickories Carya laciniosa 

            Shellbark hickory nuts usually have thick shells and large good quality kernels.  The following varieties are recommended for Kentucky.

            Fayette - Large attractive nut with a thin shell.  The kernel has good flavor, and cracks out well.  The tree bears annually and is one of the few varieties that will self pollinate.

            Henning - Rapid growing tree with a large very attractive nut.

            Keystone - Excellent cracking characteristics and kennels fall free from the shell.

            Lebanon - Junction (LJ) - Large smooth 38 g nut, sweet kernel, cracks out well early in season.

            Lindauer - Tree has healthy foliage and is a precocious heavy producer of large nuts with medium shell thickness. Nuts crack out in whole halves and it is reported to be weevil resistant..

            Selbher - Heavy bearing regular producer of thin shelled, medium sized (1 1/2  long) nuts that crack out very well; will probably self pollinate.

            Simpson #1 - Medium sized nut, very open cavity, best flavored light caramel colored kernel, heavy cropping.

            Other varieties recommended for Kentucky are:

Big Cypress                Bullnut Bradley                        Chetopa                      Henry                         

Hoagland                     Nieman            Preston 7                    Scholl                          Stauffer                      

Totten

Hybrid Hickories (Shellbark X Shagbark)

Dewey Moore - Discovered by Al Cox in OH. **********************

Mitch Russell - Precocious heavy producer of average flavor that cracks out in halves and whole kernels.

Pecans (Northern cultivars only) Carya illinoensis

            Select pecan cultivars that produce large crops of medium sized, well-filled nuts rather than Southern cultivars that produce a few large, poorly filled nuts and are more prone to winter injury.  Cultivars with resistance to scab disease should also be favored.     

            Desirable pecan nut characteristics include: less than 80 nuts/lb, greater than 50% kernel, high oil content, kernels that are light straw-color and lack of adherence of shell parts to the kernel.

            Greenriver - Nut matures in 175-180 days, has a desirable shape and excellent quality.  The tree is a heavy producer of pollen and nuts and produces a large nut with 60 to 70 nuts/lb.  It is late bearing.  Protogynous. Scab resistant

            Hirschi -

            Kanza - A new highly productive northern pecan cultivar release from the USDA with cold tolerance.  The nut has a very high quality kernel with excellent color.  It cracks mostly in halves with no packing material adhering to the dorsal or ventral grooves.  Considered to be one of the best northern cultivars. Highly scab resistant and resistant to fungal leaf scorch and leaf and stem phylloxera. It is medium in susceptibility to hickory shuckworm and other pecan insects.

            Lattus - Good late pollinator.

            Major - Nut roundish and somewhat small. The well-filled nuts run 60 to 80 nuts/lb with plump, choice, superior quality kernels.  This heavy producer is the most widely planted northern cultivar.  The late Frank Street of Henderson, KY, a highly respected fruit and nut grower, recommended that commercial plantings of 'Major' consist of 75% 'Major,' 10% 'Posey' and 15% other cultivars for trial.  Scab resistant and protandrous.

            Mohawk - Produces a large nut, 35-50 nuts/lb, with a thin shell that is 60% kernel and bears at an early age.  Requires a long season to fill and is for western Kentucky only.  As the tree gets older it tends to over produce and becomes an alternate year bearer.  Scab resistant.

            Pawnee -  Nuts have very light colored kernels that crack out well in halves. Precocious pollinates well with Posey and is very productive.  An outstanding new variety recommended for the entire state, however this variety has as only medium scab resistance.  Consequently this variety needs to be planted on a site with good air drainage and may need to be sprayed for scab on low damp sites.

            Posey - Desirable nut and kernel, 60 to 70 nuts/lb, heavy yielder, good pollen producer.  Does well in all parts of the state. Scab resistant and protogynous.

            Yates 68 - Seedling discovered in the Ed Yates nut grove.  It has 60 to 70 nuts per lb., a very thin shell and excellent kernel quality.  Yates 68 is about 59% kernel.  It is anticipated that this selection could replace the Major variety. Scab resistant.

            Yates 127 - This is an important selection discovered in the nut grove of the late Ed Yates at Chrisney, IN.  It has 65 to 70 nuts per lb, and is 55% kernel.  The nut has an extremely thin shell making it possible to extract the excellent quality kernels in one piece.  Indiana and Kentucky nut growers rate this as the best of all northern selections currently being evaluated. Scab resistant.

            Pecans normally produce 2 to 3 nuts per cluster, but have the potential to produce 8 nuts per cluster.  Consequently, cultivars that produce more than 2 to 3 nuts per cluster are of great interest, because of possible significant yield increases.

SQUIRREL DAMAGE TO NUTS

            Nut losses to squirrels may be reduced by placing a 4 ft wide tin or aluminum shield around the trunk, with the lowest portion of the shield at least 4 ft from the ground.  The shield keeps squirrels from climbing the trunk.  Bolt the shield around the tree before you expect squirrel damage (4 to 6 weeks before harvest).  Unfortunately, if squirrels can jump into your tree from another one, this technique won't work.  For other ideas about outwitting squirrels, chipmunks, rabbits and birds, consult the publication, FOR-13, Controlling Wildlife Damage in Kentucky, available at your County Extension office.

HARVESTING AND STORING NUTS

            Except for Chinese chestnuts, all nuts discussed in this publication are high in oil.  They store best if nut meats are extracted, placed in an air-tight container and frozen, because oils turn rancid more rapidly at higher temperatures.  Frozen nuts may be kept for several years or longer without loss of quality.  The next best way to store nuts is to shell them and keep them in air-tight containers in the refrigerator.

            Unshelled nuts should be placed in a cool, dry, well-ventilated location such as a garage, shed or cool root cellar.  Put them in mesh bags to promote good air circulation.  Properly cured nuts may keep a year or longer in a cool place.  See Table 2 for additional curing and storage requirements.

            Walnut and Hickory nut kernels are easier to remove if they are soaked in water for 1 to 2 hours, drained and then held in a closed container such as a covered bowl or jar for 10 hours.

            Black Walnuts are ready for harvest as soon as enough have fallen to make picking them up worthwhile.  Nuts should be hulled quickly since the stain in the hull will penetrate and discolor the nut meats if left on too long. The hull can also impart a strong, disagreeable flavor to the nut meats.

            To remove hulls, place the nuts on a hard surface and step on them or hit them with a rubber hammer.  If a large number of black walnuts need to be hulled, there are mechanical hullers available. Contact the Kentucky Nut Growers Association for details on mechanical hullers.  Wash the hulled nuts by placing them in a flat pan measuring approximately 1.5 X 2 ft that is 8 inches high.  Fill the pan about half full with nuts and direct a garden hose using high pressure to remove the remaining hull fragments and black stain. Pour off the water once or twice until nuts are clean.

            Dry them in shallow layers no more than three nuts deep for 2 to 3 weeks in a cool, dry, shady spot with good air circulation.  Crack a few nuts to be sure that kernels are good and worth storing.

            Butternuts are harvested and stored the same way as black walnuts.  However, the surface of the hull is sticky.

            Dry Persian Walnuts within 24 hours of harvesting.  They are usually dried in the shell but will dry faster if shelled first.  Screen-bottomed trays will give good ventilation and encourage drying.  The best temperatures for drying are between 95 and 105̊F.  With this procedure Persian walnuts will dry adequately in 3 to 4 days.

            Walnuts are dry when the divider between the halves of the shell breaks crisply when bent.  If it doesn't snap, it isn't dry.  If nuts are stored in their shells, they should be in a closed container.

            Gather Chinese Chestnuts as soon as they fall from the burrs.  Keep them out of the sun, since it will dry out the nuts.  Harvesting is easier if the grass under the tree is kept mowed low.  The nuts drop over a two week period and should be collected every two days.  Place nuts on a screen in a shady, cool, rather humid, well-ventilated place for several days to cure.  Chinese chestnuts have a high starch and water content and a very low oil content.  Nuts lack flavor when burrs open and chestnuts fall, but after they dry slowly for one to two weeks in a cool place (50-65̊F), starches are converted to sugars and flavor improves tremendously.

            Chestnuts should be cooked before eating and are often roasted or boiled.  To cook them in a microwave oven, puncture all but one chestnut with a knife point and put them in a covered glass casserole dish.  They are done when the unpunctured one explodes.  Boiling nuts for 3 to 4 minutes in water will make the shell soft and much easier to peel with a sharp knife when they are to be used for cooking.

            Don't Let Chestnuts Get Too Dry.  Nuts should remain nearly as plump as they were at harvest.  Chinese chestnuts may be stored by sealing whole nuts in air-tight containers and placing them in the refrigerator at 30-45̊F, or in the freezer.  If you store them in the refrigerator, check the nuts occasionally and eliminate any with mold.  Reduce mold in storage by placing the nuts in a hot water bath at 120̊F for one hour before storing. See the section on chestnut weevil control.

            Hazelnuts are harvested when they drop to the ground.  They should not be exposed to direct sunlight.  Separate empty nuts or "blanks" by floating the nuts in water.  Dry them on a screen in a shady area with good air circulation.  As hazelnuts are dried, they change texture and color.  At harvest they are firm and white, but as they dry, they first become spongy, then hard and cream-colored throughout when fully dry.  Better varieties have less shaggy wood integument around the nutmeat.  Store filberts in the same way as Persian walnuts.

            Heartnuts are harvested when they fall from the tree.  The thin hull on the nut always remains attached at harvest, but falls off after drying.  Dry nuts for several weeks in a cool, dry place.  Crack a few nuts every couple of days to check their dryness before storing.  Heartnuts store well and have a long storage life.

            Heartnuts may be eaten raw, but develop their best flavor when used in candy, baked goods or toasted in a frying pan with a little butter and salt until they darken.  They have a milder flavor than black walnuts.

            Hickory nuts vary considerably in size with the shellbark being consistently larger than the shagbark.  The excellent sweet kernels of these two nuts places them in high demand by nut consumers everywhere.  Unfortunately about the only supply comes mostly from native trees.  The best nuts are generally produced by shagbark hickory trees.  The shellbark nuts have thicker shells from which the nutmeats are not always easily extracted; however, improved selections of shellbark hickories produce nuts which compare favorably with the cracking qualities of the best shagbark nuts.

            Gather hickory nuts as soon as they fall from the tree.  Hull them and place nuts on screens to dry.  Crack a couple of nuts every few days to check for dryness.  When kernels are crisp, store nuts in their shells in a mesh bag.  A cool, well-ventilated place where squirrels cannot get to them is best.

            Hicans are harvested when they fall from the tree.  Dry and store them like hickory nuts.

            Pecans are mature on the tree when the shucks around the nut split and expose the nut.  The percentage of nuts recovered can be increased if the grass is mowed and a tarp is spread beneath the tree.   After nuts are gathered growers reduce losses to birds and squirrels by harvesting four times each season.  If pecans are allowed to drop naturally, don't let them remain on the ground long, since their quality will be reduced.  Store pecans in a well-ventilated area where they can dry without molding and sprouting.  They may then be refrigerated or frozen.

NUT CRACKING

            Table 2. provides information on the best way to crack and store Kentucky grown nuts.  There are a number of nut crackers on the market.  The following nut crackers are ones that have been tested and recommended by W. C. Donoho, a member of the Kentucky Nut Growers Association, who has an extensive collection of nut crackers. 

            When nuts are incompletely cracked, a pair of wire snips with the tips ground down to a narrow point are helpful in snipping away portions of the shell to obtain larger nut meat pieces.

Texas Native Inertia Nutcracker - This cracker does a good job on pecans, Persian walnuts and hazelnuts.  It obtains its power from rubber bands and the nuts are cracked by relaying impact through the force of inertia.  It produces primarily whole kernel halves. Around $25.00

Bill Price

P.O. Box 305

Bunn, NC 27508

Get Crackin' Nutcracker - This is a good fast cracker for many nut types including Brazil nuts.  It does not do well on black walnuts or very hard shelled nuts.  This cracker does not need to be adjusted for nut size.  Around $30.00

Creative Designs

Box 156

Goodman, MO 64843

Mr. Hickory Nut Cracker - An excellent cracker for hickory, black walnut and butternuts.  Readily adjusts for small and large nuts and does well on other nut types.  Made of box tubing and comes in two sizes, one for shagbark and one for shellbark hickories.  Around $ 70.00

Mr. Hickory Nut Cracker

Fred Blankenship

P.O. Box 1182

Radcliff, KY 40159

502/624-2712 work

Wileys Nut Grove Cracker - This is a good all purpose cracker.  The Large cracking post works well for large nuts and the smaller one works well for small nuts. The long handle provides considerable leverage for cracking hard shelled nuts.  Around $50.00

Wileys Nut Grove

1116 Hickory Lane

Mansfield, OH 44905 

Hunt Black Walnut Cracker - One of the best black walnut, butternut and hickory nut crackers.  It operates smoothly and allows very precise nut cracking, because the piston moves only 1/8 to 3/16 of an inch.  It is not easy to complete the cracking of uncracked portions of a nut, but nuts rarely need to be recracked if the cracker is adjusted properly.  Around $45.00

Hunt's Black Walnut Cracker (01)

2465 Cleveland St.

Swan, IA 50252

515/989-3869

Potter Walnut Cracker - This cracker was invented in the 1930's and is very well built and sturdy.  It does a good job on all nuts (Figure___).  The Potter Walnut Cracker adjusts quickly to the nut size and the indentations on the top of the jaws work very well to crack small hickory nuts and nuts that need additional cracking.  Priced in the $40.00 to $80.00 range depending on model.

Potter Walnut Cracker Co.

Box 930

Sapulpa, OK 74066

TABLE 2. NUT CRACKING AND STORAGE

TABLE 3.  NUT PRODUCTION PROBLEMS

(Reprinted with permission from Kansas State University MF-464, June 1978)

Symptoms                        

A. Nuts fail to begin enlarging and drop.

Cause       

1. Spring frosts may injure the flowers or small nuts.

2. Pollination may not be complete; cold, wet weather prevents good wind dispersal of pollen.

3. Cold weather after pollination.

Symptoms

B. Nuts may begin growing, then fall.

Cause

1. Insect damage (case-bearer, plant bugs or shuckworms).

2. Poor nutrition.

3. Insufficient moisture, crown gall or impaired root system.

4. Defoliation by insects or disease.

Symptoms

C. Kernels are shriveled or fail to develop normally.                   

Cause

1. Prolonged cool weather during growing season.

2. Trees heavily shaded.

3. Causes under symptom B.

Symptoms

D. Kernels have dark spots.     

Cause

1.  Insect damage.

2.  Disease damage.

MAJOR DISEASES OF NUT TREES IN KENTUCKY 

            Sometimes, diseases can limit nut production in Kentucky.  The following are some diseases most likely to be encountered by nut producers along with specific recommendations for each disease where available.

Chestnut Blight

            Chinese chestnuts are generally resistant, but not immune to chestnut blight caused by the fungus Cryphonectria parasitica.  Occasionally a Chinese chestnut tree will become infected, but this is generally not a major problem.  Chestnut blight is a major problem with American chestnuts and these trees often become blighted when they reach the age of 10 years.  Chestnut blight can also be a problem with the more susceptible American, Japanese, European, and Chinese hybrid cultivars.  This fungus causes swollen, yellow-brown, oval to irregular cankers on young twigs.  On branches and tree trunks, cankers are brown, circular to irregular in shape, with slightly raised or depressed margins.  Girdling of stems by cankers causes leaves to wilt and die.  Dead leaves and burrs cling to diseased branches well after normal leaf fall. Generally nothing can save severely infected trees, but the following method may clear up less severe infections where only a few trees are involved in a home planting.

Control

●  Prepare a soil compress by mixing soil from the base of the infected tree with enough water to produce mud.

●  Tape a piece of plastic over the canker and fill the pocket with muddy soil.  Tape the plastic at the top to prevent drying of the soil compress.  Be sure that the entire canker is covered with soil.  If the canker is large, plastic may need to be wrapped completely around the tree.  If the canker is at the base of the tree, mound soil up around the base.

●  Keep the soil compress in place for at least two months or preferably for an entire growing season.  When the compress is removed, the canker should be cured.  This treatment will not prevent new infections elsewhere on the tree or prevent reinfection of the "cured" canker.  However, if this happens, prepare another soil compress.

Crown Gall

            The bacterium Agrobacterium tumefaciens, the cause of crown gall, is widely distributed and can occur in all nut trees commonly grown in Kentucky.  Bacterium enters trees through wounds and causes formation of rounded, rough-surfaced galls, up to several inches in diameter.  Galls typically occur on roots and crown area, but may occur on the trunks and limbs as well.

            Crown gall is primarily important as a disease of nursery stock, but may cause losses in large, productive trees.  Infected nursery stock usually succumbs to the disease because of the girdling effect of galls on roots and/or main stems of affected trees.  Older infected trees show an overall reduction in vigor.  Structural decline may also be evident since disintegrating galls often provide entry points for wood-rotting fungi and insects.

            Pruning infected stock greatly increases the probability that disease will spread to uninfected stock.  Long distance spread of crown gall is primarily through movement of infected nursery stock, infested soil, or infested surface or irrigation water.  The crown gall bacterium can survive several years in soil without a host.

Control

●  Sanitation is the best way to prevent spread.  Thoroughly inspect all incoming nursery stock and destroy infected young trees as soon as you detect the disease.

●  Avoid replanting in areas where trees were known to be infected.  Fumigation of infested soil is generally not effective unless it is followed by 3 years of a non-susceptible crop before replanting with nut trees.

●  Avoid unnecessary wounding of stems and roots of healthy trees, because crown gall infections occur only at wounds.

            A few products help prevent crown gall infection or reduce its activity once infection is evident.  They require techniques that are fairly labor intensive and may not control the disease.

Bunch Disease

            Bunch disease is a problem in heartnut, Japanese walnuts, butternut, and is endemic, but rarely causes a major problem in black walnut.  It may occasionally be found in Persian walnuts and is rare in pecan.  Some growers have observed that walnut seed nuts from infected black walnut trees produce a high percentage of bunch disease infected seedlings, however this has not been confirmed by research.  It is not always possible to detect the existence of bunch disease in black walnut trees.  It is best to separate black walnut plantings from heartnuts and butternuts to reduce the chances of infection of the heartnuts and butternuts.

            The characteristic symptom of bunch disease is "brooms" of growth formed at terminals and suckers.  Brooms develop from diseased branches and form tufted masses of thin, wiry shoots with abnormally short internodes and small crowded leaves.  Dieback may occur with severe infection.

            Bunch disease is sometimes confused with zinc deficiency.  Leaflets with zinc deficiency, are narrower, thicker, and more brittle than normal.  Chlorosis generally develops between veins.  In bunch disease leaflets tend to be wider, thinner, and softer than normal.  They develop general chlorosis, not confined between veins.

            Zinc deficient terminals break dormancy when healthy terminals do.  Bunch diseased terminals, on the other hand, break 10-14 days ahead of healthy terminals.

            Brooming is a common symptom of zinc deficient terminals because dominant terminals die and side terminals proliferate.  Death of masses of main terminals is not a characteristic of bunch disease.  Instead, dieback is general and not confined to terminals.

            Bunch disease is thought to be caused by phytoplasmas that live in the inner bark's food conducting cells.  The means of natural spread of this disease has not been determined.  No insect vector is known although graft transmission has been demonstrated.

Control

            Eradication of the infected tree is the easiest and most foolproof method of control.  Although it may seem drastic, diseased trees are poor producers and the dense broomy growth of trees with bunch rot also presents problems in controlling scab and other foliar diseases. Pruning out diseased branches can be successful if the pruning is done very close to when the infection first takes place.  Once the disease becomes systemic in the tree the only control is tree removal.

Pecan Scab

            The pecan scab fungus, Cladosporium caryigenum, attacks young, rapidly growing tissue of leaves, leaf petioles, and nut shucks.  Infection is first apparent as small, circular, olive to black spots on susceptible tissues.

            Greatest damage from scab occurs to leaves, which drop, and this leads to incomplete nut filling. Infected nuts also drop.  As the season progresses and growth of trees is reduced, scab infections become less damaging to both nut yield and quality.  Scab overwinters on shucks, leaf petioles and stems infected the previous season.  Infection usually occurs just after bud break.  The fungus requires free moisture and moderate temperatures (65-85̊F) to infect pecans.  Very little infection occurs during hot, dry weather.  Secondary spore production begins within 7 to 9 days, after the fungus has colonized host tissue.

Control

            The best control is to plant scab resistant varieties. All the pecan varieties recommended in this publication have very good to excellent scab resistance.

            During wet years, scab can be extremely damaging on susceptible varieties and cause heavy losses.  Consult the spray schedule in this publication if you need control measures.  However, if it doesn't rain much in June and July, the spray schedule can be reduced considerably.

Powdery Mildew

            Powdery mildew is a common disease of nearly all nut trees grown in Kentucky.  The powdery mildew fungi, Phyllactinia corylea and Microsphaera alni, infect leaves in late summer and early fall, producing patches of white to gray fungal growth on leaf surfaces.  Tiny black spore-bearing structures are often found in these patches.  These structures remain viable on both living and dead tissue and are the means by which fungi overwinter.

Control

            Powdery mildew is seldom serious enough on most nut trees to warrant control measures.  Generally, the disease appears so late in the season that tree health and nut yield and quality are little affected.

Shoe String Root Rot

            This disease can infect all types of nut trees.  Trees infected by the fungus Armillaria mellea show a general decline in vigor as well as dieback of limbs in the tree top.  Decayed wood develops on lower trunk and root flares of affected trees.  When bark is removed from these areas, whitish wefts of the fungus or dark brown, root-like branching structures, 'shoestrings,' are usually found.

            In late fall, clumps of brown-yellow mushrooms may be seen growing around the base of affected trees.  Trees are infected through injuries by spores released from these mushrooms.  Infection can also occur through contact with 'shoestring' fragments present in surrounding soil.

            Shoe string root rot is mostly a problem on trees under considerable stress.  However, trees may decline and die without ever becoming infected by the root rot fungus.  Many die because they are planted in unsuitable locations.  Poor drainage, inadequate moisture holding capacities, low levels of nutrients,

insufficient area for root growth, etc., can contribute to a trees's decline and ultimate death.

Control

            To help avoid shoe string root rot, keep trees as healthy as possible with a regular program of fertilization, pruning, and watering during periods of drought.  Severely affected trees will not recover and should be removed (including the stump and root flares).  Do not replant a tree in the same spot.

Walnut Anthracnose

            This disease affects butternut, heartnut, and black, Japanese and Persian walnuts.

            The anthracnose fungus, Gnomonia leptostyla (Marssonina juglandis), causes irregular, dark-brown spots on leaflets in early summer.  Infection occurs in spring as spores are expelled from dead leaves on the ground.  Once infections are established, secondary spread to nearby foliage prevails.  In wet years, severe infection causes premature leaf drop and general poor condition of affected trees.  Early defoliation, if it is severe, may also result in incomplete nut fill.  If the early part of the season following bud break is dry, the disease may not be significant.

Control

            It is best to plant varieties that have a high level of anthracnose resistance, because it is difficult to spray large black walnut trees in most situations.

            For black walnut, spray with currently labeled fungicides such as 65% dodine (e.g. Syllit) starting when first leaves are half grown, and make 3 additional applications at 10-15 day intervals or as needed, depending upon prevailing conditions.  No fungicides are registered for use against anthracnose on other walnuts, butternut or heartnut.

Walnut Blight

            The bacterium Xanthomonas juglandis attacks leaves, young shoots and nuts.  Persian walnuts are more susceptible to this disease than are black walnuts.  Infections start as small, water-soaked spots that eventually turn reddish-brown.  Severely affected leaves appear twisted and curled.  New shoots are often killed by girdling stem cankers.  Diseased nuts exhibit black, sunken lesions on husks.  These lesions exude a black, slimy ooze during wet weather.  Many infected nuts fall prematurely; others remain attached and reach full size with husks, shells and kernels blackened and destroyed.  Bacteria overwinter in old nuts and in buds.

Control

            It is best to plant resistant varieties to avoid this disease.   Spray with a fixed copper solution containing at least 50% metallic copper when female flowers appear, again when 50% of the female flowers are in bloom and again when all female flowers have finished blooming.

MAJOR INSECTS OF NUT TREES IN KENTUCKY

Aphids

            These soft-bodied insects infest tree leaves during the summer and early fall and use their piercing-sucking mouthparts to remove plant sap.  Black, sooty mold can grow on "honey dew" deposited by aphids as they feed.  Heavy infestations may cause extensive leaf drop that can reduce the nut crop in current and succeeding years.

            Several species of aphids can be found on nut trees.  These black to yellow insects overwinter as eggs in bark crevices on the tree.  Eggs hatch in the spring and small aphids begin to feed on the leaves.  There are several generations during the year and winged individuals spread the population over the area.

            Usually, aphids do not become abundant enough to cause significant damage until mid- or late summer.  Examine tender terminal growth for aphid colonies at regular intervals during the growing season to detect increasing populations.  Colonies or clusters of aphids are usually found on the undersides of leaves.  Aphid infestations may become severe following use of certain pesticides.

            Thorough spray coverage is essential for satisfactory control.  Results may be less than satisfactory when aphid numbers are excessively high.  Aphids are considered secondary pests and often build to damaging numbers following the use of insecticides.

Borers

            Shot hole borers and flathead borers injure stressed or unhealthy trees.  Their exit holes may be found riddling limbs and trunks.  Adequate fertilization and water will keep trees healthy and allow them to ward off attack by borers.

            Remove dead or dying wood that is prone to borer attack and burn it.  Young trees may be protected by wrapping trunks with heavy paper or other wrapping material.

Chestnut Weevils

            Both the larger and lesser chestnut weevil may be found in Kentucky, but the lesser chestnut weevil appears to be most common.  These 1/4 inch long beetles can be identified by their long snout.  These weevils breed exclusively in Chinquapin, American, and Chinese Chestnuts.

            Adults emerge from the ground in June to July, about when chestnuts bloom.  Only a few beetles appear early and their population continues to increase during the season.  Peak numbers generally occur by the time nuts are maturing in September.

            Egg laying begins when nuts begin to form and continues through the season.  The first eggs are laid on soft wood around the forming nut.  Later eggs are laid just under the inner skin.  Most of the eggs are laid after the burr begins to open.  Small grub like larvae feed in the nut until full-grown (1/3 inch long).  They leave the nut and enter the soil to complete their development.

            Although harvested nuts may appear sound when put into storage, some will soon show obvious signs of infestation.  These infestations began while the nut was still on the tree.  Weevil infestations can be reduced by gathering nuts daily and after curing, heat them to 140̊F for 30 minutes to kill larvae in the nuts.  A cold treatment, holding nuts at 0̊F for four days may be effective, but it may affect the nuts' flavor.  Collect and destroy fallen, infested nuts before larvae have a chance to escape and enter the soil.  Trees can be jarred similar to monitoring for pecan weevil to determine the presence of adult weevils.  Sevin is the only insecticide registered for chestnuts.  Maintaining bare ground or closely mowed grass beneath the trees will aid in finding the nuts and reducing weevil populations.

General Leaf Feeders

            Several species of caterpillars may feed on nut trees.  In addition, the Japanese beetle is very fond of chestnut and May and June beetles may feed on trees as well.  Populations of these insects may vary in significance from year to year.  They may be active at different times of the growing season depending on their life cycles.

            Large trees can withstand some defoliation, but if insect damage is coupled with droughts or other stresses, the tree may lose vigor or even die.  Inspect plantings regularly to detect beginnings of insect feeding activity and to allow appropriate and well-timed spray applications as necessary.

            Unneeded sprays are a waste of money and frequent applications may produce outbreaks of mites or aphids.  Your County extension agent will be able to help identify insect pests and to help determine the appropriate recommendation.

Leaf Feeding Caterpillars

            Walnut Caterpillar - Young larvae are redbrown with narrow yellowish lines extending the length of the body.  Full-grown larvae are almost black with two gray lines on the back and two on the sides.  Many long, soft gray hairs cover the body.  Larvae feed in colonies for about three weeks.  There are two generations each year.

            Fall Webworm - Larvae are pale yellow and spotted with black.  Full grown caterpillars are about one inch long and are covered with long black and white hairs.  They produce loosely woven dirty white webs on the ends of branches.  Infestations are most common in late summer.

Mites             These tiny pests feed on the underside of leaves along midribs and produce irregular brown areas. Leaves may drop from heavily infested trees in late summer or early fall.  Mites have a short life cycle and several generations develop each year.  Outbreaks may be triggered by certain pesticide applications.

            The light green mites are just large enough to be seen with a hand lens.  Fine webbing may be seen on leaves if mite populations are very high.  Check regularly for mite infestations by carefully examining the undersides of plant leaves with a magnifying glass or by shaking leaves over a piece of white paper.  Mites falling off leaves can be seen as tiny moving dots on the paper.

Pecan Phylloxera

            Pecan phylloxera produces galls or bumps on new growth.  Leaves, twigs, or nuts may be affected.  Galls may range from 1/10 to 1 inch in diameter.  They are produced by small, soft-bodied insects closely related to aphids.  Phylloxera overwinter as eggs in bark crevices.  Tiny nymphs hatch the spring and move to feed on tender tissue.  A substance secreted by these insects causes the plant to grow abnormally, producing galls.  Several generations may occur during the growing season and infestations can continue as long as the tree has fresh, young growth.

            Insects are protected within the gall from insecticides.  Sprays may reduce continued buildup over the season but will not affect galls that have already developed.  Dormant oil spray, as recommended for scales, will help with control if applied thoroughly to the tree trunks.  This spray is targeted for overwintering eggs.  During the growing season, control should be targeted at the "crawler" stage before the galls form.  The crawler stage is active just before or at bud-break.

Pecan Spittlebug

            Pecan spittlebugs are small,soft-bodied insects that use their piercing-sucking mouthparts to remove plant sap.  They can be found inside foamy white masses on tender shoots and young nuts in spring and early summer.  There is a May and a July brood of the insect.  They occasionally can damage nuts.

Pecan Weevil

            The pecan weevil is a late season pest of pecan and hickory that may sometimes destroy a large part of the crop.  The weevil is a brown, 3/8 inch long beetle with its head extended in the form of a snout.  It is a serious threat to growers because it feeds directly on the pecan kernel.

            The adult, or weevil, appears in late August and early September, about when the nut kernels harden.  The female uses her long snout to chew a hole in the shell and deposits her eggs in the nuts.  The small white, legless grub hatches from the egg feeds inside the nut during the fall.  When mature, about 3/5 inch long, the redheaded grub chews a small hole and leaves the nut.  It drops to the ground in late fall or early winter and burrows into the soil.  Most larvae remain in the soil until the following August, pupate, and emerge as adults.  Some remain in the soil for two years before emerging as adults.

Control

            Timing of control measures is critical.  Insecticide sprays are directed at killing the adult female before she lays her eggs.  Once eggs have been deposited in the nut, they are safe from

insecticides.  The grub, or larvae, remains in the nut until full grown so does not come in contact with the insecticide.

            Apply sprays as weevils emerge from the soil and move to trees.  They often emerge after the first good rain in mid- to late August.  Determine spray timing by "jarring" trees every week starting in early August.  Put a large sheet on the ground under a tree and jar the limbs with a padded pole.  If any weevils are present, they will fall on the sheet and stay there at least long enough for you to count them.  When three or more weevils fall out of a tree, start your spray program.  Those not prepared to spray can reduce injury by periodically shaking weevils onto a harvesting sheet.  Beetles can easily be collected and destroyed.

Scales

            Several species of scale insects can damage nut trees.  Scales are often overlooked as pests because they are inactive and blend in with tree bark.  Scales suck sap from trees and severe infestations may cause symptoms ranging from leaf drop to dieback of limbs.  Trees stressed by scales become more vulnerable to attack by other pests such as wood borers.  The scale covering is the visible symptom.  This waxy material is secreted by the insect as it feeds and serves as a protective covering.  Close examination of twigs and branches is necessary to find scales.  Infested twigs may have a roughened or pitted appearance.

            Female scales overwinter under their coverings on the tree.  They lay eggs in the spring under the scale and tiny "crawlers" are active for a short time as they move to find a feeding site.  After they settle and begin to feed, they start to secrete the covering that will shield them during their life.  These insects will not move again.

            Insecticide treatments must be applied while the crawler stage is active.  Dormant oil applications will help reduce infestations.

Stinkbug

            Stinkbugs feed on a wide variety of cultivated crops and weeds.  Their feeding with piercing-sucking mouthparts causes discolorations to the kernels.  Stinkbugs feed on developing kernels before shell hardining.  Although stinkbugs cannot complete their life cycle in nut trees, adult feeding can cause serious losses.  Because stinkbug populations usually develop on weeds, effective weed management can reduce stinkbug injury.

Twig Girdler

            As the name implies, twig girdlers act as pruners on several types of nut trees and persimmon.  Symptoms include sudden twig drop in late summer or early fall.  Secondary branching may occur on trees and the number of bearing twigs is reduced.  Adults are 1/2 to 5/8 inch long gray-brown beetles that have long antennae and a red-brown head.  A broad gray band is present over the middle of the wing covers.

            Beetles are active in late summer and early fall.  The female girdles twigs and lays her eggs beyond the cut.  The larvae, unable to develop in healthy sapwood, feed for a short time and pass the winter in the twig.  They complete their development the following spring and emerge as adults in late summer.  There is one generation each year.

            Infestations may be reduced with good orchard sanitation.  Girdled and fallen twigs should be collected and burned.

TABLE 4.  PECAN PEST CONTROL GUIDE (Always read the pesticide label)

* = Rates given are dilute rates based on per acre rates using 300 gallons of spray per acre.

** = Restricted use pesticide

NOTE:  Some products have restrictions concerning the grazing of livestock on orchard floors following treatment.  Read the label of all pesticides before purchase and use.

TABLE 5.  PESTICIDES REGISTERED FOR OTHER NUT CROPS *

 * See the label for specific recommendations.