ID-77
Nut Tree Growing in Kentucky Joseph G. Masabni, John G. Strang, R. Terry Jones, Horticulture; Ric Bessin, Entomology; John R. Hartman, Plant Pathology
entucky is generally well suited for Table 1. Planting distance and estimated first deep. One or two years later, graft or growing nut trees. Northern pe- harvest of various nut trees. bud the largest of the three seedlings to K Planting First cans, black walnuts, heartnuts, hickory Distance Harvest the desired variety and remove the oth- nuts, hardy Persian walnuts (Carpath- Nut Type (feet) (years) er two. Exceptions: Chinese chestnuts ian strain), American hazelnuts, and Black Walnut 50 x 50 4-7 are not difficult to graft, but rootstock Chinese chestnuts all grow well in the Butternut 50 x 50 3‑4 incompatibility may be a problem if state. Most nut trees are grown by hob- Persian Walnut 35 x 35 5-6 the cultivar being grafted is not placed Chinese Chestnut 40 x 50 4‑5 byists and backyard gardeners. Several onto a seedling originating from this Hazelnut 15 x 15 4‑5 varieties appear to have potential for Heartnut 35 x 35 3‑4 cultivar. Hardy American or Eastern commercial production, particularly Hican 50 x 50 10-12 filberts are difficult to graft and in the some of the USDA pecan selections Hickory 50 x 50 10-12 past have been propagated by seed. and some Chinese chestnut varieties. Pecan 50 x 50 5-8 New blight-resistant varieties have been Nut trees grow best in deep, well- and will continue to be developed and drained soil of medium to good fertility available for purchase. If propagation is with a soil pH of 6.5 to 6.8. Chinese Planting Seed not feasible, grafted or budded nursery chestnuts grow best on acidic soils. Nut seeds are generally planted stock is recommended. Pecan growing in Kentucky should about 2 inches deep, soon after harvest be limited to northern varieties because in the fall. They do not germinate until Planting Trees Kentucky’s growing season is usually late spring. The “Tin Can” planting • Early spring planting of nursery nut not long enough for southern pecans to system helps reduce losses to mice, trees is better than fall planting be- mature, (i.e., for kernels to fill the shell). squirrels, and other wildlife that may cause it reduces the chance of winter Nuts of northern pecan varieties will eat them. Simply remove the top of a injury. not mature at higher elevations where tin can and, with a knife, make two • Plant trees as soon as possible after day and night summer temperatures cuts across the bottom, crossing in the delivery. vary greatly. However, trees do grow center. Push the empty can into the soil • Do not let roots dry out. Tree surviv- well on these sites and make excellent over the planted nut until the cut end al may often be improved by soaking shade trees. is flush with the soil surface. In early the tree roots in water for 24 hours If nuts of a particular variety are spring slightly turn up the metal tips at before planting. planted they will not produce a tree of the center of the can so that the seed- • Prune off broken roots and shorten that variety. Rather, to get a tree of a ling can grow through the opening but long ones before planting. certain variety, wood from that variety pests still cannot get it. As the seedling • Dig a deep hole, wide enough so that must be grafted onto a rootstock. grows, turn the tips back farther. lateral roots can spread out in their All nut trees except filberts become There is no need to remove the tin natural positions and deep enough quite large. Because nut trees take can because it usually rusts out, par- so the tap root (if there is one) will many years to fill their allotted space, ticularly if it has been burned to remove not bend. some growers plant filler trees and the galvanized coating. However, an • Leave the tap root as long as possi- remove them later, before branches of aluminum can does not rust and must ble. Trees should be planted as deep adjoining trees meet. Table 1 shows be cut down one side to permit easy as they were in the nursery. Examine suggested minimum permanent spac- removal before it girdles the young tree. tree trunks to find the soil line mark. ing and average years to first harvest If you wish to directly plant seeds • Set the tree in the hole and fill with when grafted trees are set out. instead of transplanting, then plant soil. If the soil is not too wet, firm three nuts where the tree is to mature. the soil around the roots with the Position them in a triangular pattern hands. spaced about 1 foot apart and 2 inches • Water trees well after planting to Large dead areas on the trunk usually settle the soil around the roots, and Pruning result from this type of injury. then weekly throughout the summer Remove about one-third of the top Sunscald may be prevented by paint- during dry conditions. Watering growth at planting. Cut the terminal ing the lower 30 to 36 inches of trunk trees during the first season is ex- shoot just above a bud and remove and the bases of some scaffold limbs tremely important in establishment. all side branches close to the trunk. with an interior white latex paint in • Backfill around all planted trees This encourages survival and strong the fall, by using a white plastic rodent with loose soil after rains have set- regrowth. Prune young trees lightly guard, or by wrapping the trunk with tled the soil in the planting holes. during the first few years in February aluminum foil. These actions prevent or March to select scaffold limbs with the southwest side of the tree trunk Fertilizing wide crotch angles and to maintain from heating up and help eliminate a central leader. Branches should be sunscald injury. Take a soil test and, based on its pruned off the trunk to a height of at If a white plastic rodent guard is not results, adjust soil fertility at least a least 6 feet if you plan to use a metal used around the trunk following plant- month before planting. Adjust the pH tree guard to control squirrels. When ing, place a loose cylinder of ¼-inch to 6.5 and bring phosphorus and potas- 10 to 15 good scaffold limbs that are hardware cloth at least 18 inches high sium levels into the high soil test range. well spaced on the trunk have been around the trunk. This will keep rabbits Do not fertilize at planting because developed, cut the central leader back from damaging or killing young trees. doing so can injure roots. to a lateral limb, and train the tree to Remove mulch from the base of the After the first year, follow this proce- a modified central leader shape. For trees in the fall to prevent vole damage. dure for fertilization: (1) Determine the more detailed explanations of pruning, trunk diameter 5 inches above ground. see Cooperative Extension publication, (2) For each inch of trunk diameter, Growing Fruit at Home in Kentucky Irrigation, Mulching, apply 1 lb of 10-10-10 fertilizer per (HO-64). Only limited pruning is and Weed Control tree, but no more than 1⁄3 lb of actual needed on bearing trees. Remove dead Inadequate weed control and lack of nitrogen per inch of trunk diameter limbs to a side limb or to the trunk to water are the two primary reasons for per season. (3) Place fertilizer under the promote rapid healing and avoid trunk poor nut tree growth, even death, par- tree periphery in late February. (4) Take decay. When trees are 20 to 30 years ticularly in the first season of growth. soil tests annually and apply lime as old, thin out some of the top scaffold Even mowed grass competes heavily needed to prevent soil pH from falling limbs to allow light into the interior of with young trees for nutrients and below 6.0. the trees. water. Maintain a vegetation-free area Trace elements are very important American hazelnuts are grown as a beneath the trees to reduce competi- in nut production. Zinc is the most bush and pruning consists of thinning tion from weeds. This area should be critical trace element. When zinc out smaller, weaker shoots by remov- 4 to 6 feet in diameter and expanded is lacking or present in insufficient ing them at ground level. Also, remove as the trees get older. Mulching with quantities, nutlets fail to set and yields some of the center shoots to open up wood chips, bark, hay, or straw is very are very low. Zinc is best applied as a the center of the bush, admit light, beneficial. Lay at least 4 inches of mulch foliar spray just after pollination at a and prevent bearing only on the bush for best results. Mulch should be kept rate of 1 to 2 lb of zinc sulfate/100 gal periphery. A plant should have five to at least 6 inches away from the tree base of water (1 to 2 tbsp/gal) for young trees seven main shoots. Grafted hazelnuts to avoid injury from mulch heating and and 5 to 10 lb/100 gal for mature trees. are grown as a tree and all suckers need to help reduce rodent damage. Apply two more times at two- to three- to be removed from the base. During the growing season when week intervals. For soil application, soil is dry, irrigation helps promote tree zinc chelate is recommended over zinc growth and reduce stress, especially in sulfate. Zinc chelate 10% can be applied Sunscald and the first year. On bearing trees, irriga- with liquid fertilizers as a broadcast or Rodent Protection tion will help produce larger nuts and banded treatment. Use at a maximum Young trees are particularly suscep- improve nut fill. Generally, if water is rate of 1 part zinc chelate 10% to 50 tible to sunscald injury. On bright, cold, scarce before nut shells form, nut size parts fertilizer in ammonium phos- sunny days during winter, the bark on will be reduced. Lack of water after phate solutions, or 1 part zinc chelate the southwest side of the trunk and on shell hardening inhibits kernel filling. 10% to 10 parts fertilizer in nitrogen top of northeast-growing limbs may solutions. warm up considerably. A rapid drop in temperature when the sun sets in the evening may cause vertical splits in the bark and separate bark from the trunk. tions are listed in Table 2. The pollen Pollination of Posey is shed late and will polli- Pollen of pecan, black walnut, nate female flowers of “Major” which butternut, Persian walnut, heartnut, become receptive late (see Table 2 hickory, filbert, and hican is airborne. on page 8 for more information on It is carried by wind, not insects. While pecan blooming periods). Seedlings Chinese chestnut pollen is airborne, or native pecan trees can also be some may also be carried by insects. used for pollination if they bloom at Because nut trees depend on wind the right time. A mixture of varieties and gravity to disperse pollen, pro- assures a steady, season-long pollen longed rainy periods during pollination supply. Figure 1. Unpollinated chestnut. remove pollen from the air and may • Black walnut varieties are consid- substantially reduce the nut set. ered self-fruitful, although they Nut trees have both male and female perform much better when cross- Cultivar flowers, located on different parts of the pollinated. same branch. Male flowers are catkins, • Butternuts, such as black walnuts, Recommendations which are on 1-year-old branches. are self-fruitful but will yield better for Kentucky Female or nutlet flowers resemble when cross-pollinated. They also Many of the cultivars listed in this miniature nuts and are situated at the pollinate heartnuts and are pollinat- publication can be purchased through ends of young shoot tips. The stigma ed by heartnuts. They do not cross Kentucky nut tree nurseries. If exten- is at the tip of the female flower and is easily with black walnuts. sive nut tree plantings are planned or receptive when it becomes glossy with • Persian walnuts may be either self- new cultivars are desired, individuals stigmatal fluid. Pollination takes place fruitful or partially self-fruitful. In may wish to contact the Kentucky Nut when pollen falls on the stigma. Most the latter case, pollination and nut Growers Association. Your local county nut cultivars and seedling trees are set are greatly improved by cross- Extension office can help you locate largely self-sterile because the pollen pollination with another cultivar or Kentucky nut tree nurseries and put is not ripe or is not shed from catkins seedling. Please note cultivar pol- you in contact with the Kentucky Nut when female flowers are receptive. A lination requirements in the cultivar Growers Association. variety may be either protogynous or descriptions below. protandrous. Protogynous means that • Chinese chestnuts are very self- the pistillate female flowers are recep- sterile and require other Chinese Black Walnuts Juglans nigra tive before pollen is shed from male chestnut trees within 50 to 100 feet. catkins. Protandrous means that the An unpollinated tree will produce Black walnuts begin growth late in pollen is shed from male catkins before burrs, but most will be empty inside. the spring, and there is generally little pistillate (female) flowers are receptive. Individual limbs may be grafted to problem with injury and crop loss from A mixture of varieties that shed pol- other varieties to provide pollina- late spring freezes. Problems with black len early and late is required for good tion. walnuts generally relate to poor crack- pollination. However, a mixture of • Hazelnuts or filberts are self-sterile ing qualities, disease, and alternate varieties will not automatically assure a and varieties may be either protogy- bearing. The number of nuts per pound steady, season-long pollen supply. Most nous or protandrous. is related to the cultivar planted. Light nut trees, seedlings, or grafted trees • Heartnuts are self-fruitful, but do crops produce larger nuts, while full or require medium to late pollen, some better when cross-pollinated. bumper crops produce smaller nuts. very late pollen. Most nut cultivars shed • Hicans are generally self-sterile. If pollen early, many shed very early. In they are self-sterile, they need to seasons when large quantities of pollen be pollinated by an early shedding are shed, some reports indicate that pecan such as Major. The Burton pollen has been carried by wind as far and Burlington hican cultivars are as 1 mile and has effectively pollinated self-fertile and very well suited for pecan trees. Kentucky. • Pecans are mostly self-unfruitful, • Hickory nuts may be self-fruitful in so it is very important to buy or some cases, but allowing for cross- propagate special pollinator trees to pollination is better. successfully set a full crop of nuts. Pecan pollinator cultivars or selec- Figure 2. Black walnut.
• Clermont: Medium-sized, thin- 20 to 25 nuts/lb with 39% kernel. Butternuts Juglans cinerea shelled nut, with 28% kernel. Excel- Outstanding cracking qualities. Butternuts are not generally recom- lent flavor. Heavy bearer. Resistant to Very uniform in size. Cracks well in mended in Kentucky except in the anthracnose disease. Ripens better commercial crackers. Nut separates mountains in Eastern Kentucky at in the north. Originated in Ohio. cleanly from the hull. Very produc- high elevations. They are susceptible to • Daniels: Productive variety, with 41% tive and an outstanding cultivar. bacterial canker in most areas, tend to kernel. Relatively small nut, running • Sauber No. 2: This is a sister tree to be short-lived, and rarely survive more about 32 nuts/lb. Thin shell, making the Sauber No. 1. This tree is not than 20 years. Trees are hardier than this an easy variety to crack. quite as productive as the No. 1. most walnuts and nuts have a unique • Elmer Myers: Medium-sized, thin- Excellent selection, with 37% kernel. flavor similar to that of walnuts. The shelled nut. Good cracking quality. The nut has outstanding cracking shells are thick and contain only a small Excellent flavor. Upright tree, late qualities. amount of meat. Varieties suggested on to leaf and ripen. Prolific, produces • Schrieber: The largest nuts of any cul- good sites are: in three to five years. Originated in tivar currently evaluated, with about • Ayers: Medium-sized nut. Better Ohio. 15 to 20 nuts/lb with 25% kernel. meat-to-nut percentage than most. • Emma Kay (Emma K): Medium to large, Similar to Thomas-Meyers variety. Upright tree; clean foliage. Late thin-shelled nut, excellent cracking Excellent cracking qualities and a bloomer. Originated in Michigan. quality. Excellent flavor. Prolific, very good tasting kernel. • Buckley: Large nut. Vigorous grower. bears in three to five years. Nuts • Sparrow: Medium-sized nut, running Clean foliage. Originated in Iowa. average 25 to 30 nuts/lb. Good for 25 to 30 nuts/lb. Good to excellent • Chamberlain: Large nut. Good crack- the Midwest. Originated in Illinois. cracking quality. Good, sweet flavor. ing quality. Very hardy. Originated • Hare: Large nut. Good shell structure Prolific, annual bearer. Produces in in New York. and good cracking qualities. Heavy three to five years. The tree is hardy • Craxezy: Medium-sized nut. Cracks bearer. The nut is somewhat suscep- and tends to retain its foliage later easily. Good producer. Originated in tible to husk maggots. Originated in than most other varieties. Origi- Michigan. Illinois. nated in Illinois. • Creighton: Medium-sized nut. Good • Krouse: Large nut. Annual crops. • Surprise: Nuts crack out in quarters. cracking quality. Vigorous tree. Hardy. Very productive. Nut is 26 nuts/lb. Originated in Pennsylva- Clean foliage. Well-known variety. almost identical to Daniels but has a nia. Ripens late. Originated in Michigan. better shell structure. Originated in • Thomas-Myers: Popular cross of • Weschcke: Medium to large nut. Iowa. Thomas x Elmer Myers. Large nut, Cracks well. Light kernels. Very • Leon Pounds II: Very productive. Thin 17 to 24 nuts/lb, with 35 to 40% productive tree. Extremely hardy. shell. Nice tasting. Highest crack-out kernel. Good cracker but not thin Originated in Wisconsin. percentage of any variety at 55%. shelled. Heavy bearer. Anthracnose Found by the late Leon Pounds of resistant. Ripens early. Originated Other butternut varieties suggested Gentryville, Indiana. It is believed in Missouri. Annual bearer. Begins on good sites are: Beckwith, Coble No. 1, that Elmer Meyer and a seedling of growth late in the spring, almost and My Joy. Thomas are the parents of Pounds II. two weeks later than other cultivars. • Neel No. 1: Thin shell. High crack out. One of the least frost-prone black Kernel shaped like a human heart, walnut cultivars. One of the best star at base of nut. Slow to come to black walnut cultivars for Kentucky. bearing. Excellent nut. Considered The parent Thomas cultivar is very one of the best. susceptible to anthracnose disease, • Ridgeway (Rabbit Ridge): Large nut. alternate bears and nuts do not fill, Cracks well. Bears heavily. Anthrac- therefore, Thomas is not recom- nose resistant. Two-time Kentucky mended for Kentucky. State Fair winner. Originated in Illinois. Other black walnut cultivars re- Figure 3. Butternut. • Rowher: Excellent black walnut with ported to have superior characteristics 37% kernel. Cracks easily. Kernels and now being offered in the nursery have a very light color. trade are: Beck, Football 2, and Harney. • Sauber No. 1: Large nut, averages
Hardy Persian, or English, • Somers: Large nut with 55% kernel. Walnuts Juglans regia Cracks easily. Annual bearer and early maturing. One of the greatest problems with • Utah Giant: Very large, good-quality Persian, or English, walnuts is that they nut with a sweet kernel. Very hardy. begin growth fairly early in the spring and the flowers are damaged by late Other new introductions reported spring frosts. Varieties that bear nuts to have superior characteristics are: laterally as opposed to just terminally Barton, Cascade, Fately, Lightening, tend to produce better in frost years. Figure 4. Hardy Persian, or English, walnut. McKinister, Orth, and Sigler. Poor shell structure is a problem with some varieties where the shell Chinese Chestnuts • Greenhaven: seam does not completely seal, allowing Medium to large nut. Castanea mollissima mildew to attack the kernel. Early maturing. Nuts begin to drop The male flowers, or catkins, begin about September first. The nuts fill The survival rate of grafted chest- to develop long before the female nutlet well and have well-sealed shells. This nut trees, particularly of American X flowers and are often killed by late is one of the better cultivars. Chinese hybrids, has been less than spring frosts. The Lake variety has har- • Hansen: Small- to medium-, thin- ideal due to incompatibility between dier and slower developing catkins and shelled, well-filled nut with 60% the scion and rootstock. However, often survives late spring frosts. This kernel. Excellent cracking quality. by grafting the desired cultivar onto variety should always be planted with Sweet, very good flavor. Natural seedlings from this same cultivar, losses most other cultivars that fail to produce semidwarf. Slow growing. Early from incompatibility can be almost pollen in most years. The following bearing; produces in three to five entirely eliminated. All of the following varieties are generally recommended. years. Late to leaf out. Reliably self- recommended cultivars are resistant to • Allegheny: A new variety from Penn- pollinating; good choice for limited chestnut blight. • Armstrong: sylvania, which vegetates late, misses space. Resistant to anthracnose and Chinese X American hy- frost, and can bear a full crop an- husk maggot. Ripens early. Origi- brid. Large nut, very sweet. Doesn’t nually, even after -28ºF winters. The nated in Ohio. keep long in storage. The tree bears tree is self pollinating and produces • Kaiser: Nut has outstanding quali- very well. Originated in Kentucky. • AU Leader: a medium-sized nut with a thin shell ties and is one of the largest. A large Very sweet, large nut. that has a tight seal and cracks out in nut that fills very well, seals well Excellent flavor raw or roasted. whole halves. and tastes good. Early bearer. Kaiser Released by Auburn University. • Crane: • Bedco 1: Medium to large nut. Sweet was rated as the most outstanding Chinese cultivar. Medium light kernel. Very productive. nut at the 2000 Kentucky State Fair. to large nut, 25 to 30 nuts/lb. Good • Broadview: Heavily productive. Originated from a seedling grown by cracking quality. Fine flavor. Excel- Lateral bearing. Medium to large, Richard Wilmoth in Kentucky. lent keeper. Rounded tree grows 40- round, thin-shelled nut with 47% • Lake: Medium to large, thin-shelled to 50-feet tall. Precocious; bears in kernel. Kernels are best for culinary nut. Very good quality and hardy. two to three years. Blight resistant. purposes. This is a good parent tree Cracks easily. Very good flavor and Originated in Georgia. for breeding purposes. Broadview quality. Prolific trees grow 30-feet seedlings produced from cross-pol- tall. Bears in three to five years. lination with Hansen have resulted Self-pollinating but produces better in some superior cultivars. crops when pollinated with Stark • Colby: Medium-sized, thin-shelled Champion or a seedling Carpathian nut with 53% kernel. Plump kernel. variety. Hardy in zones 5 through good flavor. Ripens early. Hardy. It 9. Originated in Illinois. This is an has self-fruitful flowers. Developed important pollinator for most other at the Illinois Agricultural Experi- varieties. ment Station. • Reda: Medium-sized, thin-shelled • Coble No. 2: Well-filled, large nut. nut. Lateral bearing. Blight and High quality. Lateral bearer. anthracnose resistant. May be a good southern variety. Originated in Figure 5. Chinese chestnut. southern Europe.
• Eaton River: Chinese hybrid. One with complete resistance to EFB, as well of the sweetest Chinese chestnuts. as Willamette, Lewis, and Clark with Large, very sweet nut. Ornamental improved resistance to EFB. Hazelnuts tree. Ripens early. Originated in bloom in the winter, and the European Connecticut. hazelnuts often have their flowers killed • Ford’s Sweet: Chinese cultivar. Small, during the winter in Kentucky. sweet kernel that resembles Ameri- Breeders have been working to de- can chestnut. Heavy bearer. Timber- velop hazelnut hybrids that are hardier type growth. Good wildlife food. than the European hazelnut and have Originated in Indiana. resistance to EFB. Hybrid hazelnut • Ford’s Tall: Chinese cultivar. Medi- cultivar releases with EFB resistance um-sized nuts. Timber-type growth are: Grand Traverse, 89-Lisa, G-22, similar to Ford’s Sweet. Reaches a 88-BS, G-14 by Cecil Farris, Lansing, height of 70 feet. Michigan; Rush and Winkler from Lan- • Mossbarger: Chinese hybrid. Large caster, Pennsylvania.; Carlola, Delores, nut, 28 to 32 nuts/lb. Sweet nut. Ex- Magdalene by Carl Weschcke, Minne- cellent keeper. Very productive. The sota; and Laroka, Eastoka, Faroka, and tree is an annual bearer. Originated Morrisoka by J.U. Gellatly in Westbank, in Kentucky. British Columbia. None of these has • Orrin: Chinese hybrid. Medium to been evaluated in Kentucky. Figure 6. Grafting incompatibility in Chinese large nut, 32 nuts/lb. Superior keep- chestnut. Native American hazelnuts are ing quality. Tree blooms slightly later mostly propagated as seedlings. How- than other varieties. ever, there are some named varieties • Qing: Produces two to four ma- American Hazelnuts, or and hybrids. Hybrids are generally not hogany colored nuts per burr with Filberts Corylus americana as hardy and often have their flowers few singles, of which 90% fall free Native American hazelnut, or filbert, killed during the winter. from burs. Very large nuts, some the Corylus americana, and the European Filazel, or Hazelbert, are crosses size of a half-dollar, 18 to 28 nuts/lb. hazelnut, Corylus avellana, are both between American hazelnut and Euro- Very sweet, well-filled with a yellow plagued by Eastern filbert blight, a pean filbert. Some of the many filazel meat. Pellicle (skin around the meat) fungal disease that eventually kills cultivars available, not widely tested in separates freely from the nut. Stores most hazelnuts grown in Kentucky. The Kentucky, are: • Bid Red: very well and considered one of the European hazelnut is the species that Large nut with moderately best cultivars. is generally grown for nut production thick shell. Well-filled kernel. Early • Sleeping Giant: Chinese X Japanese X in Oregon, and Barcelona has been the maturity. Hardy in Zone 4. • Gellatly: American hybrid. Medium to large, primary variety grown the past. Over Best-quality early filazel. Rip- high-quality, easily peeled nuts, 30 the past 10 years, Eastern filbert blight ens in September. Hardy in Zone 4. • Nut Washer: to 35 nuts/lb. Timber-type growth. (EFB) has become a serious problem in Shell is almost as thin Sweet, attractive light tan colored the Pacific Northwest, and Oregon State as an eggshell, which makes it dif- nut, making it a good market chest- University has recently released Santiam ficult to crack because it crushes nut. Developed in Connecticut. easily. Sweet flavor. Filbert-like in appearance and production. Ripens Additional cultivars now becoming midseason. available in the nursery trade are Henry VIII, Wolverine, and many others. Heartnuts Juglans ailanthifolia Seedling chestnut trees may be planted, var. cordiformis but only about 25% will bear nuts of A common problem with all heart- acceptable quality. nuts 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 dis- ease can be a problem, and it is best not to plant heartnuts near black walnut Figure 7. Hazelnut, or filbert. trees.
• Wright: Medium to large nut. Cracks • Hershey: Pecan X shagbark hickory. very well. Has a butternut-type Medium-sized nut borne in clusters flavor. Heavy bearer. Not resistant of three and four. High quality kernels to bunch disease. The tree begins fill well. Originated in Pennsylvania. growth early and is prone to frost in- • Jackson: Pecan X shagbark hickory. jury. It will pollinate Fodermaier and Medium-sized nut; tasty kernels. Marvel. Originated in Pennsylvania. Sets heavy crops when well polli- nated. Originated in Kentucky. Hicans • McAllister: Pecan X shellbark hickory. Hicans are crosses between pecan Very large nut; seldom well filled. Figure 8. Heartnut. and shellbark, shagbark, or bitternut Needs early pollen. Originated in hickory. These hybrids often have Indiana. • Canoka: Large nut. Annual, heavy mature nuts earlier than pecans and, • T-92: Large nuts (35 to 40/lb); light bearer. Leafs out one to two weeks consequently, do well in northern areas. kernel with excellent quality; one of later than other varieties and is less Unfortunately, most cultivars are rather the best. susceptible to frost injury. Origi- poor producers. nated in British Columbia. • Burton: Pecan X shagbark hickory. Additional cultivars that do well in • Fodermaier: Large nut. Cracks well. Medium-sized nut; larger, thinner Kentucky are: Dooley Burton, Johnson, Good kernel. Produces heavy to very shell than hickory parent. Excellent and Palmer. heavy crops. When over-produc- cracking quality. Excellent flavor. tion occurs, a portion of the crop Prolific tree; produces in five to Shagbark Hickories Carya ovata may tend to abort, but remaining seven years. Self-pollinating. Best • Bridgewater: Very large shagbark nuts will be fully developed. This is suited for the South and Midwest. with 47% kernel. Scab susceptible in an important cultivar and is widely Ripens early. Originated on a farm the South. Originated in Connecti- planted. Originated in New York. south of Owensboro, Kentucky. cut. • Frank: Medium-sized nut. Cracks • Bixby: Pecan X shellbark hickory. • Cook Shag: Oval flat nut that cracks well. Later to leaf out than other va- Large nut. Heavy producer. Needs out in halves. Good flavor. Origi- rieties, except for Canoka. A seedling pollination. Developed in Illinois. nated in Kentucky. selection named after the late Frank • Burlington: Pecan X shagbark • Grainger: Large nut. Cracks eas- Street of Henderson, Kentucky. An hickory. Productive cultivar. Does ily. Tree bears heavily. Ripens late. outstanding selection produces a well in the Ohio Valley. Self-pollinat- Originated in Tennessee. crop almost every year despite late ing. Originated in Iowa. • Raudabaugh: Thin-shelled nut. spring frosts. Produces an attractive • Country Club: Pecan X shagbark hick- Cracks out well. Seedling originated nut with an excellent kernel. This ory. Medium-sized nut. Very heavy from Pennsylvania. cultivar is highly recommended. producer. Originated in Indiana. • Silvis 303: Large, round, thin-shelled • Jewel Box: Productive tree. Very large • Hartmann: Pecan X shagbark hickory. nut with 45% kernel. Good quality. nut. Cracks well. Tree begins growth Medium-sized, thin-shelled nut. Self-fruitful. Good Producer. Devel- early in the spring and is more prone Good producer. Red tinted buds. oped by Ray Silvis in West Richfield, to late spring frosts. Originated in Indiana. Ohio. • Marvel: Medium to large nut that cracks well and is of good quality. Bears heavily and is hardier than Fo- dermaier. Tree begins growth early in the spring. Originated in New York. • Mitchell Hybrid: Butternut X heart- nut hybrid. Very productive with a heartnut-shaped nut. Vegetates early. • Rhodes: Large nut. Very good crack- ing quality. Excellent flavor. Prolific; produces in two to three years. Self- Figure 10. Shagbark hickory. fruitful. Begins growth later in the spring and is more resistant to frost than many other varieties. Origi- nated in Tennessee. Figure 9. Hican.
• Wilcox: Medium-sized nut. Cracks • Selbher: Heavy bearing, regular Pecans (Northern Cultivars Only) out in halves. Very good flavor. producer of thin-shelled, medium- Carya illinoinensis Prolific; bears in five to seven years. sized (1½ inches long) nuts that crack Select pecan cultivars that produce Good for the North. Ripens early. out very well; will probably self-pol- large crops of medium-sized, well-filled Originated in Ohio. linate. nuts rather than southern cultivars that • Wilmoth: Large, light-colored, thin- • Simpson No. 1: Medium-sized nut. Very produce few large, poorly filled nuts shelled nut. Good taste. Developed open cavity. Best-flavored, light cara- and are more prone to winter injury. by Leslie Wilmoth in Glendale, mel-colored kernel. Heavy cropping. Cultivars with resistance to scab dis- Kentucky. ease should also be favored. • Wurth: Large, thin-shelled nut. Additional varieties recommended Desirable pecan nut characteristics Cracks out in halves. Strong vegeta- for Kentucky are: Big Cypress, Bradley, include: less than 80 nuts/lb, greater tive growth. Very good producer Bullnut, Chetopa, Henry, Hoagland, than 50% kernel, high oil content, ker- with good scab resistance. Nieman, Preston 7, Scholl, Stauffer, and nels that are light straw-colored and lack • Yoder No. 1: Nut cracks easily. Excel- Totten. adherence of shell parts to the kernel. lent flavor. Bears young and heav- Pecans normally produce two to ily. Developed by Emmet Yoder in three nuts per cluster but have the po- Smithfield, Ohio. tential to produce eight nuts per cluster. Consequently, cultivars that produce Additional recommended varieties more than two to three nuts per cluster include: Abundance, Cody Cox, Etter, are of great interest because of possible Neel, Porter, Sauber, and Walters. significant yield increases. Shellbark Hickories Carya laciniosa Shellbark hickory nuts usually have Table 2. Pecan blooming periods. thick shells and large, good-quality Period when: Pollen Flowers are kernels. The following varieties are Cultivars is shed receptive recommended for Kentucky: Giles early medium • Daulton: A very vigorous-growing Gibson early late variety that produces very large nuts. Pawnee early late • Fayette: Large, thin-shelled nut with Major early late to very late 33% kernel. The kernel has good Peruque early late flavor and cracks out well. The tree Kentucky medium medium Greenriver medium medium bears annually and is one of the Hirschi early late few varieties that will self-pollinate. Colby late early Originated in Pennsylvania. Figure 11. Shellbark hickory. Posey late early • Henning: A rapid-growing tree that Mohawk medium-late early to mid produces a large, very attractive nut. Kanza late early • Keystone: Best cracking shellbark. Lattus late medium Kernels fall free from the shell. De- Hybrid Hickories Hodge late very late veloped in Pennsylvania. (Shellbark X Shagbark) Howle late late • Lebanon Junction (LJ): Large smooth • Mitch Russell: Kiowa late early to mid Precocious heavy Witte very late early to medium nut (38 g or 1.3 oz/nut). Sweet kernel. producer of average flavor that Yates 127 medium late Cracks out well. Early in season. cracks out in half and whole kernels. Yates 68 early late Originated in Lebanon Junction, Annual bearer found in Bloomfield, For more information on these and other pecan Kentucky. varieties, including photos, go to: Kentucky, in 1993.
• Major: Medium-sized, round nut (60 to 80 nuts/lb). Thin, easy-to-crack Squirrel Damage shell. Small, plump, sweet, buttery, to Nuts golden kernels. Excellent flavor. Beau- Nut losses to squirrels may be tiful, vigorous tree produces heavily. reduced by placing a 4-foot-wide tin Bears in three to five years. Plant with or aluminum shield around the trunk, Colby or Stark Surecrop to ensure with the lowest portion of the shield proper pollination. Ripens medium- at least 4 feet from the ground. The early. Hardy in Zones 6 to 8. Scab re- shield keeps squirrels from climbing sistant and protandrous. Discovered the trunk. Bolt the shield around the Figure 12. Pecan. in Henderson County, Kentucky. tree before you expect squirrel damage • Mohawk: Large nut (35 to 50 nuts/lb). (four to six weeks before harvest) to • Colby: Medium to large nut (55 to 60 Very thin shell. 60% of kernel is meat. occur. Unfortunately, if squirrels can nuts/lb). 50% of kernel is meat. Good Fills well. Cracks easily into fancy jump into your tree from another one, flavor. Tree quickly reaches a mature halves. Distinctive flavor. Excellent this technique won’t work. The follow- height and width of 40 feet. Heavily quality. Vigorous, upright tree with ing publications are available at your productive; bears young after seven diffuse branching and dark green county Extension office. to eight years. Pollinate with Green foliage. Very productive. Bears at a • Managing Tree Squirrel Problems in River Hirschi, Major, Peruque, or young age. Blooms late. Plant with Kentucky (FOR-45):
Walnut and hickory nut kernels are Butternuts are harvested and stored eliminate any with mold. Reduce mold easier to remove if they are soaked in the same way as black walnuts. How- in storage by placing the nuts in a hot water for one to two hours, drained, ever, the surface of the hull is sticky. water bath at 120ºF for one hour before and then held in a closed container such Persian walnuts should be dried storing. See the section on chestnut as a covered bowl or jar for 10 hours. within 24 hours of harvesting. They are weevil control on page 16. usually dried in the shell but will dry Hazelnuts are harvested when they Table 3. Nut storage. faster if shelled first. Screen-bottomed drop to the ground. They should not Best Long- trays will give good ventilation and be exposed to direct sunlight. Separate Type of Curing Area Term Storage encourage drying. The best tempera- empty nuts, or “blanks,” by floating the Nut Requirements Technique º Black cool, dry shell & freeze tures for drying are 95 to 105 F. With nuts in water. Dry them on a screen in Walnut this procedure Persian walnuts will dry a shady area with good air circulation. Butternut cool, dry shell & freeze adequately in three to four days. As hazelnuts are dried, they change Persian dry at 95-105°F shell & freeze Walnuts are dry when the divider texture and color. At harvest they are Walnut within 24 hr after harvest between the halves of the shell breaks firm and white, but as they dry they Chinese shady, cool, boil or roast, crisply when bent. If it doesn’t snap, first become spongy, then hard and Chestnut humid, well remove shell & it isn’t dry. If nuts are stored in their cream-colored throughout when fully ventilated freeze shells, they should be in a closed con- dry. Better varieties have less shaggy Hazelnut shady, well shell & freeze ventilated tainer. wood integument around the nutmeat. Heartnut cool, dry shell & freeze Chinese chestnuts should be gathered Store filberts or hazelnuts the same way Hican cool, dry shell & freeze as soon as they fall from the burrs. Keep as Persian walnuts. Hickory cool, dry shell & freeze them out of the sun because it will dry Heartnuts are harvested when they Pecan cool, dry shell & freeze out the nuts. Harvesting is easier if the fall from the tree. The thin hull on the grass under the tree is kept mowed low. nut always remains attached at harvest The nuts drop over a two-week period but falls off after drying. Dry nuts for Black walnuts are ready for harvest and should be collected every two days. several weeks in a cool, dry place. Crack as soon as enough have fallen to make Place nuts on a screen in a shady, cool, a few nuts every couple of days to check picking them up worthwhile. Nuts rather humid, well-ventilated place for their dryness before storing. Heartnuts should be hulled quickly because the several days to cure. Chinese chestnuts store well and have a long storage life. stain in the hull will penetrate and have a high starch and water content Heartnuts may be eaten raw, but discolor the nut meats if left on too and a very low oil content. Nuts lack they develop their best flavor when long. The hull can also impart a strong, flavor when burrs open and chestnuts used in candy and baked goods or disagreeable flavor to the nut meats. fall, but after they dry slowly for one to when toasted in a frying pan with a To remove hulls, place the nuts on two weeks in a cool place (50 to 65ºF), little butter and salt until they darken. a hard surface and step on them or hit starches are converted to sugars and They have a milder flavor than black them with a rubber hammer. If a large flavor improves tremendously. walnuts. number of black walnuts need to be Chestnuts should be cooked before Hickory nuts vary considerably in size, hulled, there are mechanical hullers eating and are often roasted or boiled. with the shellbark hickory nut being available. Contact the Kentucky Nut To cook them in a microwave oven, consistently larger than the shagbark Growers Association for details on me- puncture all but one chestnut with a hickory nut. The sweet kernels of these chanical hullers. Wash the hulled nuts knife point and put them in a covered two types place them in high demand by placing them in a flat pan measuring glass casserole dish. They are done by nut consumers everywhere. Un- approximately 1 ½ by 2 feet wide and when the one not punctured explodes. fortunately, most of the supply comes 8 inches high. Fill the pan about half Boiling nuts for three to four minutes from native trees. The best nuts are full with nuts and direct a garden hose in water will make the shell soft and generally produced by shagbark hickory using high pressure to remove the re- much easier to peel with a sharp knife trees. The shellbark nuts have thicker maining hull fragments and black stain. when they are to be used for cooking. shells from which the nutmeats are not Pour off the water once or twice until Don’t let chestnuts get too dry. Nuts always easily extracted; however, im- nuts are clean. should remain nearly as plump as they proved selections of shellbark hickories Dry them in shallow layers no more were at harvest. Chinese chestnuts produce nuts that compare favorably than three nuts deep for two to three may be stored by sealing whole nuts in with the cracking qualities of the best weeks in a cool, dry, shady spot with air-tight containers and placing them in shagbark nuts. good air circulation. Crack a few nuts to the refrigerator at 30 to 45ºF or in the Gather hickory nuts as soon as they be sure that kernels are good and worth freezer. If you store them in the refrig- fall from the tree. Hull them and place storing. erator, check the nuts occasionally and nuts on screens to dry. Crack a couple
10 of nuts every few days to check for dry- Table 4. Nut cracking. Blankenship, P.O. Box 1182, Radcliff, ness. When kernels are crisp, store nuts Type of KY 40159, 502-624-2712 (work). Nut To Shell: in their shells in a mesh bag. A cool, • Wileys Nut Grove Cracker: This is a Black apply pressure either end-to-end well-ventilated place where squirrels Walnut across longest dimension or side- good, all-purpose cracker. The large cannot get to them is best. to-side across widest dimension cracking post works well for large Hicans are harvested when they fall Butternut apply pressure either end-to-end nuts and the smaller one works across longest dimension or side- from the tree. Dry and store them as to-side across widest dimension well for small nuts. The long handle you do hickory nuts. Persian apply pressure side-to-side not on provides considerable leverage for Pecans are mature on the tree when Walnut suture line after harvest cracking hard-shelled nuts. It costs the shucks around the nut split and Chinese peel with a knife about $50 and can be ordered from: Chestnut expose the nut. The percentage of nuts Hazelnut any way Wileys Nut Grove, 1116 Hickory recovered can be increased if the grass Heartnut tap lightly on sharp point with a Lane, Mansfield, OH 44905. is mowed and a tarp is spread beneath hammer • Hunt Black Walnut Cracker: One of the the tree. After nuts are gathered, Hican apply pressure on suture, side-to- best black walnut, butternut, and hick- side across widest dimension growers can reduce losses to birds and ory nut crackers. It operates smoothly Hickory apply pressure side-to-side across squirrels by harvesting four times each widest dimension and allows very precise nut cracking season. If pecans are allowed to drop Pecan any way because the piston moves only ⅛ to 3⁄16 naturally, don’t let them remain on the of an inch. It is not easy to complete ground long because their quality will the cracking of uncracked portions • Get Crackin’ Nutcracker: be reduced. Store pecans in a well-ven- This is a good of a nut, but nuts rarely need to be tilated area where they can dry without fast cracker for many nut types, cracked again if the cracker is adjusted molding and sprouting. They may then including Brazil nuts. It does not do properly. It costs about $45 and can be refrigerated or frozen. well on black walnuts or very hard- be ordered from: Hunt’s Black Walnut shelled nuts. This cracker does not Cracker, 2465 Cleveland St., Swan, IA Nut Cracking need to be adjusted for nut size. It 50252, 515-989-3869 costs about $30 and can be ordered • Potter Walnut Cracker: This cracker Table 4 provides information on the from: Creative Designs, Box 156, was invented in the 1930s and is very best way to crack and store Kentucky- Goodman, MO 64843. well built and sturdy. It does a good grown nuts. There are a number of nut • Mr. Hickory Nut Cracker: An excellent job on all nuts. The Potter Walnut crackers on the market. The following cracker for hickory, black walnut, and Cracker adjusts quickly to the nut nut crackers are ones that have been butternuts. Readily adjusts for small size and the indentations on the top tested and recommended by W. C. and large nuts and does well on other of the jaws work very well to crack Donoho, a member of the Kentucky nut types. Made of box tubing and small hickory nuts and nuts that Nut Growers Association who has an comes in two sizes, one for shagbark need additional cracking. It costs extensive collection of nut crackers. and one for shellbark hickories. It about $40 to $80 and can be ordered When nuts are incompletely costs about $70 and can be ordered from: Potter Walnut Cracker Co., cracked, a pair of wire snips with the from: Mr. Hickory Nut Cracker, Fred Box 930, Sapulpa, OK 74066. 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 Figure 13. Texas Native Inertia Nutcracker. relaying impact through the force of inertia. It produces primarily whole Figure 14. kernel halves. It costs about $25 and Mr. Hickory Nut Cracker. can be ordered from: Bill Price, P.O. Box 305, Bunn, NC 27508
Figure 15. Hunt Black Walnut Cracker.
11 Table 5. Nut production problems. Control Symptoms Cause Major Diseases of Nut Nuts fail to 1. Spring frosts may injure Generally, nothing can save severely begin enlarg- the flowers or small Trees in Kentucky infected trees, but the following meth- ing and drop nuts Sometimes, diseases can limit nut od may clear up less severe infections 2. Pollination may not be complete; cold, wet production in Kentucky. The following where only a few trees are involved in a weather prevents good are some diseases most likely to be en- home planting. wind dispersal of pollen countered by nut producers along with 3. Cold weather after pol- • Prepare a soil compress by mixing lination specific recommendations for each soil from the base of the infected Nuts may be- 4. Insect damage: case- disease where available. tree with enough water to produce gin growing, bearer, plant bugs, or mud. then fall shuckworms Chestnut Blight 5. Poor nutrition • Tape a piece of plastic over the 6. Insufficient moisture, Chinese chestnuts are generally canker and fill the pocket with crown gall, or impaired root system resistant but not immune to chestnut muddy soil. Tape the plastic at the 7. Defoliation by insects blight caused by the fungus Cryphonec- top to prevent drying of the soil or disease tria parasitica. Occasionally, a Chinese compress. Be sure that the entire Kernels are 8. Prolonged cool weather chestnut tree will become infected, but shriveled or during growing season canker is covered with soil. If the fail to develop 9. Trees heavily shaded this is generally not a major problem. canker is large, plastic may need to normally 10. Causes 4-7 above Chestnut blight is a major problem be wrapped completely around the Kernels have 11. Insect damage with American chestnuts and these dark spots 12. Disease damage tree. If the canker is at the base of Reprinted with permission from Kansas State trees often become blighted when they the tree, mound soil up around the University MF-464, June 1978. reach the age of 10 years. Chestnut base. blight can also be a problem with the • Keep the soil compress in place for more susceptible American, Japa- at least two months or, preferably, nese, European, and Chinese hybrid for an entire growing season. When cultivars. This fungus causes swollen, the compress is removed, the canker yellow-brown, oval to irregular cankers should be cured. This treatment on young twigs. On branches and tree will not prevent new infections trunks, cankers are brown, circular to elsewhere on the tree or prevent irregular in shape, with slightly raised re-infection of the “cured” canker. or depressed margins. Girdling of stems However, if this happens, prepare by cankers causes leaves to wilt and die. another soil compress. Dead leaves and burrs cling to diseased branches well after normal leaf fall.
Figure 16. An American chestnut stem with Figure 17. Dead branch a chestnut blight canker (Castanea dentata due to infection by chestnut with a Cryphonectria parasitica canker). The blight canker. fungus enters through wounds, such as the broken branch stub on the left, and grows in and under the bark, killing the cambium. Figure 18. Closeup of a branch stub after chestnut blight canker Fungus breaks through the lenticels to sporu- infection reached the main trunk. late. Photo by R. A. Jaynes, courtesy of the Connecticut Agricultural Experiment Station, New Haven, Connecticut.
12 Crown Gall A few products help prevent crown Bunch disease is sometimes con- gall infection or reduce its activity once fused with zinc deficiency. Leaflets with The bacterium Agrobacterium infection is evident. They require tech- zinc deficiency, are narrower, thicker, tumefaciens, the cause of crown gall, niques that are fairly labor intensive and more brittle than normal. Chloro- is widely distributed and can occur and may not control the disease. sis generally develops between veins. In in all nut trees commonly grown in bunch disease leaflets tend to be wider, Kentucky. Bacterium enters trees Bunch Disease thinner, and softer than normal. They through wounds and causes formation develop general chlorosis, not confined of rounded, rough-surfaced galls, up to Bunch disease is a problem in heart- between veins. several inches in diameter. Galls typi- nut, Japanese walnuts, and butternut Zinc deficient terminals break cally occur on roots and crown area, and is endemic, but rarely causes a major dormancy when healthy terminals but they may occur on the trunks and problem, in black walnut. It may occa- do. Bunch-diseased terminals, on the limbs as well. sionally be found in Persian walnuts and other hand, break 10 to 14 days ahead of Crown gall is primarily important pecans. Some growers have observed healthy terminals. as a disease of nursery stock, but it may that walnut seed nuts from infected black Brooming is a common symptom cause losses in large, productive trees. walnut trees produce a high percentage of zinc-deficient terminals because Infected nursery stock usually suc- of bunch disease-infected seedlings; dominant terminals die and side ter- cumbs to the disease because of the however, this has not been confirmed minals proliferate. Death of masses of girdling effect of galls on roots and/or by research. It is not always possible to main terminals is not a characteristic main stems of affected trees. Older in- detect the existence of bunch disease in of bunch disease. Instead, dieback is fected trees show an overall reduction black walnut trees. It is best to separate general and not confined to terminals. in vigor. Structural decline may also black walnut plantings from heartnuts Bunch disease is thought to be be evident because disintegrating galls and butternuts to reduce the chances of caused by mycoplasma-like organ- often provide entry points for wood- infection of the heartnuts and butternuts. isms that live in the inner bark’s food rotting fungi and insects. The characteristic symptom of bunch conducting cells. The means of natural Pruning infected stock greatly disease is “brooms” of growth formed at spread of this disease has not been increases the probability that disease terminals and suckers. Brooms develop determined. No insect vector is known, will spread to uninfected stock. Long from diseased branches and form although graft transmission has been distance spread of crown gall is primar- tufted masses of thin, wiry shoots with demonstrated. ily through movement of infected abnormally short internodes and small, nursery stock, infested soil, or infested crowded leaves. Dieback may occur surface or irrigation water. The crown with severe infection. gall bacterium can survive several years in soil without a host. Control • Sanitation is the best way to prevent spread. Thoroughly inspect all in- coming 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. Fu- migation of infested soil is generally not effective unless it is followed by three years of a nonsusceptible crop before replanting with nut trees. Figure 20. Advanced stage • Avoid unnecessary wounding of of bunch disease. Courtesy of stems and roots of healthy trees
13 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 dis- eases. Pruning out diseased branches can be successful if the pruning is done Figure 21. Pecan scab very close to when the infection first symptoms. takes place. Once the disease becomes systemic in the tree, the only control is tree removal. Pecan Scab The pecan scab fungus, Cladospori- um caryigenum, attacks young, rapidly growing tissue of leaves, leaf petioles, and nut shucks. Infection is first ap- parent as small, circular, olive to black spots on susceptible tissues. Powdery Mildew Shoestring Root Rot Greatest damage from scab oc- Powdery mildew is a common This disease can infect all types of curs to leaves, which drop, leading to disease of nearly all nut trees grown in nut trees. Trees infected by the fun- incomplete nut filling. Infected nuts Kentucky. This is not the same patho- gus Armillaria mellea show a general also drop. As the season progresses and gen that causes powdery mildew on decline in vigor as well as dieback of growth of trees is reduced, scab infec- grape (Uncinula necator) or vegetable limbs in the tree top. Decayed wood tions become less damaging to both nut crops (Sphaerotheca fuliginea, Ery- develops on lower trunk and root flares yield and quality. Scab overwinters on siphe cichoracearum). The powdery of affected trees. When bark is removed shucks, leaf petioles, and stems infected mildew fungi, Phyllactinia corylea and from these areas, whitish wefts of the the previous season. Infection usually Microsphaera alni, infect leaves in fungus or dark brown, root-like branch- occurs just after bud break. The fungus late summer and early fall, producing ing structures, called shoestrings, are requires free moisture and moderate patches of white to gray fungal growth usually found. º temperatures (65 to 85 F) to infect on leaf surfaces. Tiny black spore-bear- Clumps of brown-yellow mushrooms pecans. Very little infection occurs dur- ing structures are often found in these may be seen growing around the base ing hot, dry weather. Secondary spore patches. These structures remain viable of affected trees in late fall. Trees are production begins within seven to nine on both living and dead tissue and are infected through injuries by spores days, after the fungus has colonized the means by which fungi overwinter. released from these mushrooms. Infec- host tissue. tion can also occur through contact Control Control with shoestring fragments present in Powdery mildew is seldom serious surrounding soil. The best control is to plant varieties enough on most nut trees to warrant Shoestring root rot is mostly a that are scab-resistant. All the pecan control measures. Generally, the dis- problem on trees under considerable varieties recommended in this publica- ease appears so late in the season that stress. However, trees may decline and tion have very good to excellent scab tree health and nut yield and quality are die without ever becoming infected by resistance. little affected. the root rot fungus. Many die because During wet years, scab can be they are planted in unsuitable locations. extremely damaging on susceptible va- Poor drainage, inadequate moisture rieties and cause heavy losses. Consult holding capacities, low levels of nutri- the spray schedule on page 19 if you ents, insufficient area for root growth, need control measures. However, if it etc., can contribute to a tree’s decline doesn’t rain much in June and July, the and ultimate death. spray schedule can be reduced consid- erably.
14 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 even- tually 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 Figure 22. Shoestring root rot. husks, shells, and kernels blackened and destroyed. Bacteria overwinter in Control affected trees. Early defoliation, if it is old nuts and in buds. To help avoid shoestring root rot, severe, may also result in incomplete keep trees as healthy as possible with a nut fill. If the early part of the season regular program of fertilization, prun- following bud break is dry, the disease ing, and watering during periods of may not be significant. drought. Severely affected trees will not Control recover and should be removed (includ- ing the stump and root flares). Do not It is best to plant varieties that have a replant a tree in the same spot. high level of anthracnose resistance be- cause it is difficult to spray large black Walnut Anthracnose walnut trees in most situations. This disease affects butternut, heart- For black walnut, spray with current- nut, and black, Japanese, and Persian ly labeled fungicides such as 65% dodine walnuts. The anthracnose fungus, Gno- (e.g., Syllit) starting when first leaves are monia leptostyla (Marssonina juglan- half grown, and make three additional dis), causes irregular, dark brown spots applications at 10- to 15-day intervals or Figure 24. Walnut blight symptoms on New as needed, depending upon prevailing Zealand grown walnuts. Courtesy of on leaflets in early summer. Infection
Figure 23. Anthracnose spots on a black walnut leaf. Courtesy of
Figure 26. Chestnut weevil larvae and the exit hole they Figure 25. Female chestnut weevil make. on sweet chestnut leaf. Courtesy of The American Chestnut Foundation at
16 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 recom- mendation. Leaf-Feeding Caterpillars • Walnut caterpillar: Young larvae are red-brown with narrow yellowish Figure 27. Active feeding by nearly mature cat- Figure 28. Fall webworm netting in a choke- erpillars. Courtesy of Kentucky State University cherry. Courtesy of Michael Masiuk (pho- lines extending the length of the Research and Extension at
17 Pecan Spittlebug Control Insecticide treatments must be ap- plied while the crawler stage is active. Pecan spittlebugs are small, soft-bod- Timing of control measures is Dormant oil applications will help ied insects that use their piercing-suck- critical. Insecticide sprays are directed reduce infestations. ing mouthparts to remove plant sap. at killing the adult female before she They can be found inside foamy white lays her eggs. Once eggs have been Stinkbug masses on tender shoots and young nuts deposited in the nut, they are safe from in spring and early summer. There is a insecticides. The grub, or larva, remains Stinkbugs feed on a wide variety of May and a July brood of the insect. They in the nut until full grown so it does not cultivated crops and weeds. Their feed- occasionally can damage nuts. come in contact with the insecticide. ing with piercing-sucking mouthparts Apply sprays as weevils emerge from causes discolorations to the kernels. the soil and move to trees. They often Stinkbugs feed on developing kernels emerge after the first good rain in mid- before shell hardening. Although to late August. Determine spray timing stinkbugs cannot complete their life by “jarring” trees every week starting in cycle in nut trees, adult feeding can early August. Put a large sheet on the cause serious losses. Because stinkbug ground under a tree and jar the limbs populations usually develop on weeds, with a padded pole. If any weevils are effective weed management can reduce present, they will fall on the sheet and stinkbug injury. stay there at least long enough for you Twig Girdler to count them. When three or more weevils fall out of a tree, start your As the name implies, twig girdlers spray program. Those not prepared act as pruning agents on several types to spray can reduce injury by periodi- of nut trees and persimmon. Symptoms Figure 30. Pecan spittlebug. Courtesy of include sudden twig drop in late sum- Clemson University—USDA Cooperative cally shaking weevils onto a harvesting Extension Slide Series, www.forestryimages. sheet. Beetles can easily be collected mer or early fall. Secondary branching org. and destroyed. may occur on trees and the number of bearing twigs is reduced. Adults are ½- Pecan Weevil Scales to ⁵⁄8-inch-long, gray-brown beetles that Several species of scale insects can have long antennae and a red-brown The pecan weevil is a late-season damage nut trees. Scales are often head. A broad gray band is present over pest of pecan and hickory that may overlooked as pests because they are the middle of the wing covers. sometimes destroy a large part of the inactive and blend in with tree bark. Beetles are active in late summer crop. The weevil is a brown, 3⁄8-inch-ong Scales suck sap from trees and severe and early fall. The female girdles twigs beetle with its head extended in the infestations may cause symptoms and lays her eggs beyond the cut. The form of a snout. It is a serious threat to ranging from leaf drop to dieback of larva, unable to develop in healthy sap- growers because it feeds directly on the limbs. Trees stressed by scales become wood, feed for a short time and pass the pecan kernel. more vulnerable to attack by other winter in the twig. They complete their The adult, or weevil, appears in late pests such as wood borers. The scale development the following spring and August and early September, about covering is the visible symptom. This emerge as adults in late summer. There when the nut kernels harden. The waxy material is secreted by the insect is one generation each year. female uses her long snout to chew a as it feeds and serves as a protective Infestations may be reduced with hole in the shell and deposits her eggs covering. Close examination of twigs good orchard sanitation. Girdled and in the nuts. The small white, legless and branches is necessary to find scales. fallen twigs should be collected and grub hatches from the egg feeds inside Infested twigs may have a roughened or burned. the nut during the fall. When mature, pitted appearance. about 3⁄5-inch long, the redheaded grub Female scales overwinter under chews a small hole and leaves the nut. It their coverings on the tree. They lay drops to the ground in late fall or early eggs in the spring under the scale, and winter and burrows into the soil. Most tiny “crawlers” are active for a short larvae remain in the soil until the fol- time as they move to find a feeding lowing August, pupate, and emerge as site. After they settle and begin to feed, adults. Some remain in the soil for two they start to secrete the covering that years before emerging as adults. will shield them during their life. These insects will not move again. Figure 31. Twig girdler.
18 Table 6. Pecan pest control guide.* Disease or Weed Control Insect Chemical Rate/100 gal1 Rate/gal Comments Dormant stage in Nut Trees Phylloxera, Dormant Oil (97%) 3.5 gal ½ cup Apply when temperature is Because most available herbicides Obscure above 40° F. are selective, there will always be some Scale escapes, which, if not controlled, will Bud break to 3 inches of new growth Phylloxera Asana XL2 2-5.8 floz -- 21 day PHI become the dominant weeds in the Brigade WSP2 4-16 oz -- 7 day PHI grove. To prevent this, do not depend Centric 40 WDG 1-1¼ oz -- 14 day PHI on herbicides exclusively. Cultivate, hoe, Lorsban 50WP 1 lb -- 28 day preharvest interval or pull escapes. Rotate herbicides and (PHI). Limit five applications/ season. be sure to use herbicides with differing Proaxis 0.5 EC2 1.28-2.56 floz -- 14 day PHI modes of action in rotational crops. Provado 1.6 F 1.75-3.5 floz -- 7 day PHI Mixing two or more herbicides Malathion 57% EC 0.6 pt -- Repeat as necessary. improves the spectrum of weeds Sevin 80 S 1.25-3 lb 1¼-3 tbsp 14 day PHI Warrior2 1.28-2.56 floz -- 14 day PHI controlled, while minimizing required Pecan scab Syllit 65% WP 1 lb 1 tbsp Scab pressure intensifies rates. However, do not mix herbicides Benlate 50% WP 2.7-5.3 oz 1 tsp once night temperatures unless the mixture is approved on at Topsin-M 70% WP 2.1-4.3 oz 1 tsp reach 55°F. least one label of the products intended Orbit 1.3-1.8 floz -- for use. Abound 3.1-4.1 floz ¼ tsp Nut crops can be easily injured if too Ziram 76W 2 lb 2 tbsp Super-Tin 80W 1.7-2.5 oz ½ tsp much herbicide is applied. To prevent Enable 2F 2.7 floz ¼ tsp this, calibrate the sprayer before each 1st cover, soon after pollination when tips of nuts turn brown (mid-May to early-June) use and adjust nozzle tips to the proper Pecan scab as above as above as above height above soil level. Herbicides 2nd cover through shuck split should be applied with a boom sprayer. Pecan scab as above as above as above Apply fungicides during pe- riods of frequent rains at 10- Backpack sprayers are not recommend- to 14-day intervals. Do not ed for commercial orchards because apply fungicides after shuck they do not provide uniform applica- split. Only limited fungicide sprays may be needed during tion of herbicides. Airblast sprayers very dry periods. should not be used because herbicide Early to mid-August following a heavy rain tank residue can burn foliage when Pecan Weevil Imidan 70 WSP 1 lb -- 14 day PHI spraying insecticides or fungicides. Asana XL2 2.0-5.8 floz -- 21 day PHI Baythroid2 1.0-1.2 floz -- 14 day PHI Controlling Weeds Sevin 80 S 1.25-3 lb 1¼-3 tbsp Do not apply after shuck split. 14 day PHI Before Planting 2 Mustang Max 1.28-2.0 floz -- 21 day PHI Many of the worst weeds are peren- Proaxis 0.5 EC2 1.28-2.56 floz -- 14 day PHI Warrior2 1.28-2.56 floz -- 14 day PHI nials such as quackgrass, Johnsongrass, Apply insecticides for these pests only when they become a problem in the pecan grove yellow nutsedge, Canada thistle, and Aphids Admire Pro 7-14 oz/acre -- 7 day PHI field bindweed. Perennials spread and Soil applied, reproduce mainly by underground rhi- see label Brigade WSP2 4-16 oz -- 7 day PHI zomes and are more difficult to control Centric 40 WDG 1-1.25 oz -- 14 day PHI once nut crops are planted. Therefore, Dimethoate 4 EC 0.3 pt -- 21 day PHI eliminate all perennial weeds before Malathion 57% EC 0.5-1 pt -- 21 day PHI establishing a new planting by using a 2 Mustang Max 1.28-2 oz -- 21 day PHI planned program of tillage, rotational Nexter 75WP 2.6 to 5.33 oz -- 7 day PHI Proaxis 0.5 EC2 1.28-2.56 floz -- 14 day PHI crops, and herbicides. After planting, Provado 1.6 F 1.75-3.5 floz -- 7 day PHI continue to hoe them any time they Sevin 80 S 1.25-3 lb 1¼-3 tbsp 14 day PHI appear. Time and money spent before Thionex 50 WP 1.5 lb 1½ tbsp For black-margined aphid. planting will eliminate the need for Warrior2 1.28-2.56 floz -- 14 day PHI more costly and ongoing weed control continued on next page methods during the establishment and production years. Without the pres- ence of competing perennial weeds, there will be a greater potential for
19 Table 6. Pecan pest control guide, continued. vigorous, healthy establishment of the Disease or nut planting. Insect Chemical Rate/100 gal1 Rate/gal Comments Roundup applied directly to the foli- Leaf-feeding Asana XL2 2-5.8 floz -- 21 day PHI caterpillars Baythroid2 1.2-1.4 floz -- 7 day PHI age of perennial weeds before plowing Brigade WSP2 4-16 floz -- 7 day PHI is the most effective means of control. Confirm 2F 4-8 floz -- 14 day PHI Roundup application must be timed Intrepid 2 F 2-4 floz -- 14 day PHI correctly and the right rate used for Mustang Max2 1.28-2 floz -- 21 day PHI Imidan 70 WSP 1 lb -- 14 day PHI the perennial weeds you are trying Lorsban 50 WP 1-2 lb -- 28 day PHI. Limit 5 applica- to control. Most perennials are best tions. controlled with fall-applied Roundup. Malathion 57% EC 0.6 pt -- 21 day PHI Grasses should be at least 8 inches tall Proaxis 0.5 EC2 1.28-2.56 floz -- 14 day PHI Sevin 80 S 1.25-3 lb 1¼-3 tbsp 14 day PHI when treated. An extended period Spintor 2 SC 1-2.5 floz -- 14 day PHI of drought just before spraying may Thionex 50 WP 1.5-2 lb 1-2 tbsp 21 day PHI adversely affect control. Spring applica- Warrior2 1.28-2.56 floz -- 14 day PHI tions are effective on grasses but do not Pecan Admire Pro 7-14 floz -- 7 day PHI provide as good control of broadleaf spittlebug soil applied, see label perennials as fall applications. Asana XL2 2-5.8 floz -- 21 day PHI Baythroid2 1-1.2 floz -- 14 day PHI Methods of Application Imidan 70 WSP 1 lb -- 14 day PHI Uniform application is absolutely Proaxis 0.5 EC2 1.28-2.56 floz -- 14 day PHI Provado 1.6 F 1.75-3.5 floz -- 7 day PHI necessary if herbicides are to provide Sevin 80 S 1.25-3 lb 1¼-3 tbsp 14 day PHI the desired results. Variations in the Warrior2 1.28-2.56 floz -- 14 day PHI spray pattern, speed of the rig, worn Mites Acramite 50 WS 0.375-0.5 lb -- 14 day PHI nozzle tips, etc., may change the ap- Dimethoate 4 EC 0.3 pt -- 21 day PHI plication rate sufficiently to damage the Envidor 2 SC 7 - 9 floz -- 7 day PHI Malathion 57% EC 0.5-1 pt -- 21 day PHI crop or reduce weed control. Devrinol, Nexter 2.6-5.33 oz -- 7 day PHI Karmex, and some formulations of Si- Savey 50 DF 1.5-3 oz -- 28 day PHI mazine (Princep) are wettable powders Zeal 1-1.5 oz -- 28 day PHI that do not easily dissolve in water. When rosette is a problem These herbicides form a suspension in Zinc defi- Zinc sulfate 25 WP 1 lb 1 tbsp Apply at bud break and at 1st ciency cover. water that needs constant agitation in 1 Rates given are dilute rates based on per acre rates using 200 gallons of spray per acre. the spray tank. Consequently, you must 2 Restricted use pesticide NOTE: Some products have restrictions concerning the grazing of livestock on orchard floors follow- take several precautions to maintain a ing treatment. Read the label of all pesticides before purchase and use. uniform application. *Always read the pesticide label in full. Precautions 1. Screens in the line should be no more than 50 mesh to avoid clog- ging. Table 7. Pesticides registered for other nut crops.* 2. The material will settle to the bot- Crop Pesticides Registered Comments tom of the tank if not constantly agi- Walnut Acramite, Agri-Mek, Apollo, Asana, tated. Either continuous mechanical Baythroid, Brigade, Confirm, Diazinon, agitation by paddles in the tank or Envidor, Esteem, Guthion, Imidan, Intrepid, Kelthane, Lorsban, Malathion, hydraulic agitation by return flow Nexter, Pounce, Proaxis, Savey, Sevin, jets (pressure regulator bypass) is SpinTor, Thionex, Warrior necessary. Chestnut Acramite, Baythroid, Brigade, Confirm, For the chestnut weevil apply 2.5-3.75 Envidor, Esteem, Imidan, Intrepid, Proaxis, lb/100 gal or 2-3 tbsp/gal. Make 4 ap- 3. Wettable powders are abrasive; Nexter, Savey, Sevin, SpinTor, Warrior plications at weekly intervals. Begin in therefore, do not use these her- late July, end before shuck split. bicides in gear, roller, or impeller * See the label for specific recommendations. pumps. The clearances in these posi- tive displacement pumps are close; they wear quickly when abrasives are pumped.
20 4. Wettable powders wear nozzles Newly planted trees are especially Table 8. Herbicides cleared for nut crops. readily, too. Brass nozzles wear sensitive to herbicides. Crop tolerance sooner than polymer and stain- increases in late summer and fall. This less steel nozzles. Because of wear, corresponds to the time when preemer- the amount of spray being pushed gence herbicides can be used to control Walnut Butternut Chestnut Hazelnut Heartnut Hican Hickory Pecan through the nozzle will gradually many winter annual and perennial Preemergence Chateau 51WDG x x x increase. The spray rig must be prop- weeds. Devrinol 50DF x x x erly designed and calibrated often Remember that light, sandy soils Gallery 75DF x x x (approximately every 20 hours of use require less herbicide than heavier soils Goal 2XL x x x x x x with brass nozzles) if you are to be for comparable levels of weed control. Karmex 80DF x x sure of the amount of material being Nut crops growing on soils low in or- Princep 4L x x x applied per acre. ganic matter are especially prone to her- Prowl 3.3EC x x x x bicide injury. Accordingly, lower rates of Sandea 75DF x x x x x x Water Volumes and herbicide should be used on fields low Snapshot 2.5TG x x x Adjuvants with Roundup/ in organic matter (less than 2%). Solicam 80DF x x x Surflan 4AS x x x x x Touchdown (Glyphosate) To minimize the risk of crop injury, Treflan HFP 4EC x x Low water volumes of 5 to 10 gallons growers must be careful not to exceed XL 2G x x x per acre provide best weed control. If maximum recommended annual ap- Postemergence higher water volumes must be used, use plication rates. Fully understand and Aim 2EC x x x x x x the maximum rate of glyphosate for the follow the instructions on the product Amine4 x x x x x x x x weed to be controlled. At high water labels. Do not expect herbicides to con- Gramoxone x x x x x x volumes, adding a non-ionic surfactant trol all weed problems. Understand that MSMA-6 Plus x x x x x x x x hand weeding and cultivation will be re- Poast 1.5EC x x x x x x x x at 0.5% (1 pint in 25 gal) or ammonium Recoil 3.2E x x x x x x x x sulfate (2 to 4 lb per acre) to the spray quired to obtain complete weed control. Weakened plants are more susceptible Reglone 2L x mix will improve control. Always add Roundup 5.5L x x x ammonium sulfate to the water before to herbicide injury. Conversely, healthy Select 2EC x x x x x adding glyphosate. Hard water with plants are most capable of tolerating more than 500 parts per million of cal- recommended treatment rates. cium or magnesium will usually reduce glyphosate activity. If hard water must Table 9. HRAC code, risk of resistance, signal word, restricted use, and preharvest intervals of herbicides labeled on nut trees. be used, keep the volume low (5 gal per HRAC Risk of Signal Restricted Preharvest acre) or increase the rate of herbicide. Trade Name Common Name Code Resistance Word Use Interval Use clean water. Silt, clay, and organic Preemergence debris in water will also reduce glypho- Chateau 51WDG flumioxazin E Medium Caution No 60 d sate activity. Devrinol 50DF napropamide K3 Low Caution No 35 d Gallery 75DF isoxaben L Medium Caution No - Herbicide Injury Goal 2XL oxyfluorfen E Medium Warning No - Karmex 80DF diuron C2 Medium Caution No - Crop injury resulting from the use of Princep 4L simazine C1 Medium Caution No - herbicides is common, particularly on Prowl 3.3EC pendimethalin K1 Low Caution No - light sandy soils. Most herbicide injury Sandea 75DF halosulfuron B High Caution No - Snapshot 2.5TG trifluralin + isoxaben L,K1 Medium Caution No - can be traced to using too high a rate Solicam 80DF norflurazon F1 Medium Caution No 14 d on light soils, incorrect timing of sprays, Surflan 4AS oryzalin K1 Low Caution No - incorrectly calibrated sprayers, sensitive Treflan HFP 4EC trifluralin K1 Low Caution No - cultivars, and weak plants growing un- XL 2G benefin + oryzalin K1 Low Caution No 1 yr der unfavorable conditions. The grower Postemergence usually has some control over these Aim 2EC carfentrazone E Medium Caution No 3 d Amine4 2,4-D amine O Low Danger No 14 d factors. Any factor that injures the crop Gramoxone paraquat D Medium Poison Yes - (other pests, winter injury, exposure of MSMA-6 Plus MSMA Z Low Caution No 1 yr root systems as a result of erosion, im- Poast 1.5EC sethoxydim A High Warning No 14 d proper mineral nutrition, wet spots in Recoil 3.2E 2,4-D + glyphosate G,O Low Danger No 40 d Reglone 2L diquat D Medium Warning No - the field, etc.) will make the crop more Roundup 5.5L glyphosate G Low Caution No 14 d susceptible to injury. Select 2EC clethodim A High Warning No -
21 Table 10. Herbicide application information for nut trees.* Material and Rate/A Weed Problem Comments and Limitations Preemergence Chateau 51WDG Annual broad- Nonbearing trees only: The preferred timing is in the fall to maximize the potential for rain- (flumioxazin 51% ai) leaves, suppres- fall to activate and set the herbicide. Do not apply to trees less than one yr old, or to mature 6-12 oz/15-75 gal water sion of grasses trees after bloom through final harvest, unless with hooded or shielded application. Apply alone preemergence or tank mix with Roundup or Gramoxone postemergence with a crop oil 1% v/v or NIS 0.25% v/v. Do not incorporate. Do not allow drift to contact foliage or green bark. Max. rate is 6 oz per season if trees are less than three years old. Min. 30 days between applications. PHI = 1 year. Devrinol 50DF Annual grasses Apply from late fall prior to soil freeze-up to early spring prior to weed emergence. If no rain- (napropamide 50% ai) and broadleaves fall occurs within 24 hours after treatment, cultivate or irrigate 1 in to activate. Apply alone to 8 lb/20 gal (min.) water weed-free soil or in tank mix with Roundup or Gramoxone. Do not allow spray to contact nuts or foliage. May be applied to newly planted and established crop. Max. one application per season. PHI = 35 days. Gallery 75DF Most broad- Nonbearing trees only: Apply in late summer to early fall; or preemergence in early spring (isoxaben 75% ai) leaves prior to weed germination or immediately after cultivation. Do not apply to new transplants 0.66-1.33 lb/10 gal (min.) until soil has settled with no cracks present. Rainfall or irrigation 0.5” is needed within 21 days water of application. Not effective on germinated weeds. Min. 60 days between applications. Max. rate is 4 lb per acre. Goal 2XL Annual broad- Dormant application only: Effective both preemergence (5-8 pt) and postemergence (2-8 (oxyfluorfen 2 lb ai/gal) leaves, suppres- pt) as a directed spray on weeds <4 in. Do not apply from bud swell till harvest completion. 2-8 pt/40 gal (min.) water sion of grasses Can be mixed with other preemergence herbicides or with Roundup or Gramoxone. Max. rate is 8 pt per year. Karmex 80DF Annual grasses Make an initial treatment of 4-5 lb in the last fall or early winter after harvest. Repeat annually (diuron 80% ai) and broadleaves with 3-4 lb in the fall. Can also apply 2 lb in the fall, followed by 2 lb in the spring. Apply as a 4-9 lb/25-40 gal water directed spray, avoiding contact of foliage with spray or drift. Do not graze livestock in treated groves. Do not replant treated areas to any crop within two years after last application, as injury to subsequent crops may result. Princep 4L Annual grasses Apply 2-4 qt in the fall or as a split application of 2 qt in the fall and spring. Apply under trees (simazine 4 lb ai/gal) and broadleaves established at least one year for hazelnut and walnut and two years for pecans. Apply in 2-4 qt/40 gal (min.) water spring before weeds emerge avoiding contact with nuts, foliage, or stems. Max. one applica- tion per year. Do not apply when nuts are on the ground. Prowl 3.3EC Annual grasses Nonbearing trees only: Do not apply if buds have started to swell. May be applied preplant (pendimethalin 3.3 lb ai/gal) and certain incorporated, preplant surface or preemergence. For best results, rain or irrigation is needed 2.4 qt/20 gal (min.) water for broadleaves within 21 days of application. Not effective on germinated weeds. Do not allow spray to short-term control contact leaves, shoots, or buds. For new plantings, do not apply until soil has settled and no 4.8 qt/20 gal (min.) water for cracks are present. long-term control Sandea 75DF Annual broad- Apply as a directed spray to trees established at least 12 months and where the soil has firmly (halosulfuron 75% ai) leaves and yel- settled around the roots from packing and rainfall or irrigation. Avoid contact with trunk, 0.66-1.33 oz/20 gal water low nutsedge foliage, roots or stems. Snapshot 2.5TG (granular) Annual grasses Nonbearing trees only: Apply preemergence on weed-free clean soil. For best results, 0.5 in (isoxaben+trifluralin 2.5% ai) and certain rain or irrigation is needed within 3 days of application. Not effective on germinated weeds. 100-200 lb broadleaves Min. 60 days between applications. Max. rate is 600 lb per year. Solicam 78DF Annual grasses Apply a directed spray to settled and firm soil from fall to early spring before weeds emerge (norflurazon 78.6% ai) and broadleaves, and before shaking or nut drop. Soil should be settled and firm. Rainfall or irrigation 0.5 in is 2.5-10 lb/20 gal (min.) water suppression of needed within four weeks. Do not contact nuts or foliage. yellow nutsedge Surflan 4AS Annual grasses Make a single band or broadcast application to the ground beneath trees before weeds (oryzalin 4 lb ai/gal) and certain emerge. Apply alone to weed-free soil or postemergence mixed with Roundup or 2-6 qt/20-40 gal water broadleaves Gramoxone. Rainfall or irrigation 0.5 in is required for activation. Min 2.5 months between applications. Max. rate is 12 qt per year. Treflan HFP 4EC Annual grasses New plantings: Apply 1.25-2 pt and incorporate before transplanting. (trifluralin 4 lb ai/gal) and broadleaves Established plantings: apply 2-4 pt and incorporate prior to period of weed germination or 1.25-4 pt/5-40 gal water after removal of weeds with tillage or herbicides. XL 2G (granular) Annual grasses Nonbearing trees only: Apply only to established plantings. Apply preemergence to weed- (benefin + oryzalin 1 lb ai/50 and broadleaves free soil or immediately after cultivation. A 0.5” rainfall or irrigation is needed within 21 days lb bag) of application for herbicide activation. Min. 4 months between applications. Max. rate is 900 200-300 lb lb per year.
continued on next page
22 Table 10. Herbicide application information for nut trees, continued. Material and Rate/A Weed Problem Comments and Limitations Postemergence Aim 2EC Annual broad- Apply any time during the season. Always add non-ionic surfactant 0.25% v/v or crop oil 1% (carfentrazone 2 lb ai/gal) leaves v/v. Mix with Roundup or Gramoxone for broader weed control. Max. 7.9 floz per year. Min. 14 1-2 floz/20 gal water days between applications. PHI = 3 days. Sucker management: Apply when suckers are green. Do not allow spray to contact nuts, foliage, or green bark. Amine4 Annual and Apply as directed spray to annuals 1-2 in high and to perennials up to early bud stage. Do (2,4-D) some perennial not allow spray to contact leaves, nuts, or limbs of tree. Use coarse spray and low pressure to 3 pt/5-25 gal water broadleaves avoid drift. Nonbearing trees must be established at least one year. On bearing trees. Do not apply during bloom or after before irrigation. Do not apply to bare ground. Max. two applica- tions per year and 75 days between applications. PHI = 60 days. Chateau 51WDG Annual broad- See “Preemergence” section above for details. (flumioxazin 51% ai) leaves, suppres- 6-12 oz/15-75 gal water sion of grasses Goal 2XL Annual broad- See “Preemergence” section above for details. leaves Gramoxone Inteon 2L Most an- Apply as directed spray to actively growing weeds. Repeat applications are necessary to give (paraquat 2 lb ai/gal) nual grasses sustained control. Apply as a coarse spray. Always add nonionic surfactant 0.25% v/v or crop 2.5-4 pt/10 gal (min.) water and broadleaves oil 1% v/v. Do not allow spray to contact leaves, nuts, or green stems. Do not apply when nuts weeds, top kill of are on the ground. Max. 5 applications per year. Restricted Use Pesticide. perennial weeds Karmex 80DF Annual grasses See “Preemergence” section above for details. and broadleaves Poast 1.5EC Annual and pe- Apply as a directed spray to actively growing grass before tillering. Always add crop oil 1.25% (sethoxydim 1.5 lb ai/gal) rennial grasses v/v. Max. rate is 2.5 pt per application and 7.5 pt per season. PHI = 14 days. 1.5-2.5 pt/25 gal water Recoil 3.65E Annual and pe- Use on nonbearing (well established, 1 yr or older) and bearing trees before and after bloom. (glyphosate + 2,4-D) rennial grasses Max. 2 applications per season. Min. 75 days between treatments. PHI = 14 days. Apply as a 1-4 qt/15-100 gal water and broadleaves directed and shielded spray with flat-fan nozzles and low pressures (20-25 psi). Avoid contact with nuts, foliage, stems, or lower limbs. Apply when soil is moist and do not irrigate for 5-7 days after application. Roundup WeatherMax 5.5EC Annuals and Rate depends on weed species and stage of growth. See label for details. Apply as preplant (glyphosate 5.5 lb ai/gal) some peren- broadcast application or in fall for control of roots and rhizomes of perennial weeds or as a di- 0.5-3.3 qt/10-40 gal water nial grasses and rected spray or wiper application (20-100% solution) to actively growing weeds in established broadleaves plantings. Always add AMS 8.5-17 lb/100 gal in hard water or drought conditions. Do not al- low spray to contact any part other than mature bark. Does not provide residual control; can be mixed with labeled preemergence herbicides. Allow min. three days between application and transplanting. MSMA 6 Plus Annual grasses Nonbearing trees only: Apply as a postemergence directed spray. Max. three applications 2.66 pt/50-100 gal water and broadleaves per year. Do not allow spray to contact foliage, stem or bark. Reglone 2L Annual grasses Nonbearing trees only: Apply postemergence as a directed spray using a shield for contact (diquat 2 lb ai/gal) and broadleaves burn of weeds. Complete coverage is essential for good control. Can be used during site 1.5-2 pt/15 gal (min.) water preparation and up to 1 year of harvest. Do not allow contact with green stems, foliage or fruits. Do not use for food or feed for one year after application. Select 2EC Most annual Nonbearing trees only: Apply postemergence as a directed spray to actively growing grass- (clethodim 2 lb ai/gal) and perennial es before tillering. Do not use crop oil. Always add non-ionic surfactant at 0.25% v/v. May be 6-8 floz/20-30 gal water grasses applied as a spot treatment at 0.65-1.3 floz per gal. Rainfast in one hr. Max. rate is 32 floz per year. *Consult label for full application instruction before use.
23 The authors wish to thank Fred Blankenship, John Brittain, Ed Canty, Roby Kight, Leslie Wilmoth, and the late W.C. Donoho and Henry Converse for their help in preparing this publication.
Educational programs of Kentucky Cooperative Extension serve all people regardless of race, color, age, sex, religion, disability, or national origin. Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, M. Scott Smith, Director of Cooperative Extension Service, University of Kentucky College of Agriculture, Lexington, and Kentucky State University, Frankfort. Copyright © 2007 for materials developed by University of Kentucky Cooperative Extension. This publication may be reproduced in portions or its entirety for educational or nonprofit purposes only. Permitted users shall give credit to the author(s) and include this copyright notice. Publications are also available on the World Wide Web at www.ca.uky.edu. Issued 5-2007