1988 Year End Report for the SONG Project: Commercial Nut Tree Crops for Ontario
In the fall of 1985, the Ontario Government initiated a new farm program entitled: Ontario Crop
Introduction and Expansion Program. The Society of Ontario Nut Growers (SONG) is now
ending its third year in the program and offers this report, submitted by the seven participants in
the project at seven different sites. The objectives of the project are:
#1 - To determine the commercial potential of the sweet chestnut cultivar "Layeroka".
#2 - To grow, identify and evaluate outstanding sweet chestnut, Persian Walnut filbert (hazel), heartnut and pine nut trees.
#3 - To determine experimentally, the influences of certain factors on such things as growth rates, nut production, and disease susceptibility.
Site #1 - R. Douglas Campbell, R.R.#1, Niagara-on-the-Lake ON LOS 1JO
The bloom period extended from March 21 to April 10. Frosts had some moderate impact during the middle of the bloom season. Most hazels suffered from severe moisture stress during the July drought. Application of irrigation prevented serious loss of productivity. Harvest started on September 6 and extended to October 10. Selections such as NC1 produced at the extended rate of 2200 pounds per acre. Generally, 1988 production exceeded 1987 but was less than 1986.
Bloom started in the first week of May with very little evidence of frost injury. Nut size was established before the mid summer, drought took effect. Trees that were not watered had difficulty filling kernels. Walnut blight and husk maggot infestation were" prevalent during August to September. Cultivars such as Somers started dropping ripe nuts September 6 and finished harvesting on September 28. Hansen started dropping nuts on September 15; McKinster on September 20; NC1 on October 5. Production rates on an extended basis were for Somers, 2600 pounds per acre and respectively for Hansen 1500; McKinster 1900 and NC1 1800.
The chestnut bloom season extended from June 25 to July 17. It was very apparent that the several Layeroka types were not producing any pollen. NC1 and NC2 which are seedlings of the cultivar Abundance produced plenty of good pollen. Also, seedlings of the Douglass strain of Chinese/American chestnut hybrids are generally proficient at producing viable, early season pollen so essential for setting good crops on Layeroka. The chestnuts showed severe drought stress during mid summer and all benefited enormously from irrigation. Layeroka started dropping mature nuts on September 21 and was finished harvesting by October 8. NC1 and NC2 produced first ripe nuts on October 1 and Mahogany on October 3. The overall chestnut harvest was finished by October 26. A few of the Douglass strain seedlings produced the occasional first nuts in the September 20-22 period. The combination of hot weather, high fertilization and irrigation produced nuts which were unusually large. Layeroka seedling nuts were 21 to the pound and the corresponding rates for others were: NC1 23; NC2 28; Mahogany 30. The production rates on an extended per acre basis were: Layeroka seedlings 2200 pounds; Mahogany 2100 pounds; NC1 1900 pounds; NC2 1700 pounds. The 1988 crop represented the third year of consistent productivity, although 1987 was slightly better.
The first vegetation of the heartnuts in 1988 was slightly earlier than the average but no spring frost damage resulted. Crops were reduced on some trees because of less than normal production of pistillate bloom. Catkin bloom was full and effective. Percentage pollination/fertilization of pistillate bloom was about 90%. Bunches of nuts went as high as 16 and 17 per cluster.
The heartnuts experienced severe drought stress in July-August in the form of yellowing and dropping of basal leaves on the new growth. The impact of the drought was substantially reversed by the application of irrigation. The first nut drop of harvest began on September 17. CW3 was the first to ripen. 1988 revealed a reversal of the ripening order of the selections. Usually, CW3 is about one week later ripening than CW1. The production rates on an extended per acre basis were: CW3 2300 pounds; CW1 900 pounds.
Fifteen seedlings of CW3/CW1 came into production in 1988. Trueness to the "valentine" shape and easy cracking form was about 50%. Several of the seedlings show high productivity tendencies and high numbers of pistillate flowers per cluster.
The production of several pecan clones and selections was very promising. Good production and nut maturity was evident in Colby, Snag, Best's Early, Cornfield, Theresa Foster, Carlson #2, NC7, NC11, S24, and NC4. The seedling selection NC4 was good enough in size and flavour to be ranked with many of the "southern" varieties of Georgia and Texas. The pecans showed excellent drought resistance throughout the 1988 season. The shuck-slit stage of the pecans mentioned above varied from as early as October 16 to as late as November 3. However, most of the filling is complete about three weeks before shuck break. The passage of about three weeks from shuck break and the occasional light frost will bring the nuts to the machine shakable stage. Snag, Best's Early, Carlson #2, Lucas, NC4, NC11, and S24 were remarkable in being 95% harvestable with one shake about the second week of November. If the nuts are mature, the occasional frost does not detract from the quality of the kernels. Therefore, in commercial pecan districts, the nuts may be harvested throughout the winter months if nut pickup is delayed by fall rains. The extended yields of the various trees on the basis of pounds per acre yield were: Colby 2900; S24 2000; Lucas 1900; NC4 1900; Snag 1300; Best's Early 1200; Carlson #2 1100; and NC11 600.
In 1988, the almonds started into flowering April 10, about as early as has been observed in the last six years. Although the weather was both wet and frosty during a long flowering season, the almonds went on to produce a good crop. The almonds showed better drought resistance than many of the other nut tree species, but they did profit from irrigation.
Harvest started with first nut drop on September 20 and was substantially complete by October 16. There was a great deal of variation in both flowering and harvesting of almonds with two weeks difference or more in the extremes. Again, it was found that very few of the insects and diseases of the near relative, the peach, affect the almond. The freedom from spraying requirements is both a major environmental and economic advantage. The extended harvest rates of pounds of nuts in the shell per acre were: NC2 14, 200; NC1 6500; NC3 2900.
Several of the other nut species such as the shellbark hickories and the sweet kernel apricots had a very good year in 1988. The best hickories were Henry and Fayette in that order. Henry is exceptional for high production and kernel quality. Also, nut size is very large compared to the wild hickories of Ontario. NC1 and NC2 are apricots which have sweet and delicious kernels like almonds. Most of the harvest is completed in the last two weeks of July.
SITE #2 - Ernest Grimo, R.R.#3, 979 Lakeshore Road, Niagara-on-the-Lake, Ontario LOS 1 JO
Ernest Grimo has 6 acres of Persian walnuts, 3 acres of sweet chestnuts, 1.2 acres of hybrid hazels and a two year old heartnut planting of about 0.5 acres. Most of the walnuts are grafted cultivars under test to determine their commercial potential. The chestnuts are largely hand-pollinated seedlings of Layeroka being grown to develop new selections. The hazel hybrids are made up of good parent sources in an effort to develop new cultivars also. The following is the 1988 evaluation.
Hazelnut Orchard (Corylus species)
Since this orchard is designed to test individual trees for cultivar status, little effort has been made to maximize production. Instead, poorer trees have been removed and sites were replanted to test new seedlings. This has resulted in a planting that has a wide age range from one year to fifteen years. In 1987, 20 out of 209 trees or 10% of the planting was replaced with young seedlings as part of the upgrading program. In 1988, 22 more of the seedlings are slated for removal. Most of these trees suffered from top dieback of 20% or more of the tree. Since it was not a severe winter, the condition is believed to have been caused by fluctuating spring temperatures which occurred in early spring when catkins were in bloom. Though most would recover from this condition, tfiese trees are no longer considered suitable candidates for cultivar selection.
The heavy crop of 1986 was followed by a lighter crop in 1987. There was a larger crop in 1988. There was a total crop of 265 kg (584 lb.). This is an increase of 33% despite the removals and a serious spring drought which affected current season leaf size and new growth. Surprisingly, nut size and fill was not seriously affected. The stress of the 1988 growing season may well take its toll in 1989.
In determining our best selections for commercial production, many factors are taken into consideration. These include nut features, bearing habits and harvesting characteristics. Selections which rate highly for nut quality and size may also tend to drop poorly or stick in the husk. This is true of most of the NY numbers in the orchard when grown in the Niagara area. Conversely, the Gellatly strain are earlier ripening and usually drop free. We favour the Gellatly strain as the genetic line that will produce our best commercial selections, though the NY strain has many worthy nut qualities.
Nut production is the one most important characteristic of a commercial cultivar. The following table ranks the ten best selections according to nut yield for the last three years. The trees were also rated on a five point scale (one is high) for each of those years. The ratings take into consideration all of the tree and nut qualities for the past four years. Please note that some distortion of figures may result when individual trees are expressed in hectare scale. Size of tree may also affect production rates. Small trees may appear more productive. Chinoka and Grimo 188P are the smallest trees in the group while Gellatly 502 is the largest in area. The trees marked with an asterisk are from the Gellatly strain.
The following table by itself does not automatically determine the best overall selections for the three year period. Though Chinoka was the highest yielder, it only rated a four in 1988. Many of the nuts were unusually small and were difficult to remove from the husks this year for the first time. The heavy annual production along with the drought could have caused this stress reaction. Gellatly 502 had its poorest crop and smallest nuts also this year. There was a striking difference in the yield and nut size of the NY and the Gellatly strains as well. The Gellatly trees were sizing up the nuts during the late June, July drought period, while the NY hybrids sized up several weeks later w
hen adequate moisture requirements returned. Taking everything into consideration, we would rate the following as our best selections for test planting: Gellatly 502, Grimo 188P, Chinoka, NY 616, NY 200 and NY 686.
|Hazelnut Orchard Evaluation Record|
Persian Walnut Orchard (Juglans regia)
On a scattered planting of about 5 acres, and over 200 trees, there are two different studies being made. In the first, 60 selections and cultivars have been grafted onto black walnut rootstocks. These trees are being fruited and evaluated over the long term to determine the best cultivars. The number of replications vary from one to ten or more of each cultivar. In the second, there are about 50 seed grown selections which are also being grown for cultivar status. In this planting, the poorest rated trees are removed annually and replaced with new seedlings.
Thus far none of the seedlings have measured up to the quality and production of our cultivars. On the other hand, we have a number of Hansen seedlings which are proving themselves to be productive with good quality nuts, carrying with them many of Hansen's good features including lateral bearing. Hansen seedlings are so reliable from seed, that we believe that Hansen seedlings could be used in a commercial planting at a substantial savings in startup costs. As soon as the poor ones are identified, they can be June budded to superior clones. An alternative arrangement is to closely interplant grafted cultivars with Hansen seedlings. Later when the trees are getting too crowded, the Hansen seedlings can be removed. This would increase production in the early years of the orchard.
The spring drought which caused the hazels much stress, was a bonus for the Persian walnuts. Only one copper spray was applied to control walnut blight this year. No more were needed since this bacterial disease requires rain to spread. The July and August rain came at the right time to size up and fill the nuts well. Quality was very good this year overall, while nut production is about average.
Production records on the cultivar planting are unfair for most of our best cultivars. These trees are the most heavily cropped for scion wood which we use for the production of nursery stock, our major farm business. This removes the best fruiting wood from the trees and can substantially reduce the nut crop. This is true of most of the low rates shown below.
Another factor which affects production is the age and vigour of the trees. Younger, fast growing trees have less bearing surface and tend to have lighter crops. The following table is offered as a guide. It represents our best cultivars ranked in order first for nut quality, then production. All production rates are based on fresh harvested nuts before drying. After drying there would be a weight loss of 20% to 50%.
|(Ratings: 1 high, 5 low)||1987||1988|
Sweet Chestnut Orchard (Castanea mollissima)
The chestnut planting consists of about 250 trees on nearly one hectare of land. About 90% of the planting is made up of hand pollinated crosses using the cultivar "Layeroka" as the seed parent. Though some of the planting is 14 years old, most of the trees are under 5 years old. Each year the planting is upgraded, eliminating trees that do not meet selection criteria.
Nut production on most of the seedlings has tended to be erratic. Most of the larger trees that have survived the removal program had good crops of nuts. Many of the 5 ear olds and younger trees did not bear again this year. The best performer for the third year in a row was Grimo 142Q. It was our earliest ripening tree this year, dropping nuts by the first of October. Layeroka and the Campbell selections dropped about two days later. All of the above selections appear promising as they are regular annual bearers. Nut size can vary with Layeroka and the Campbell selections as they tend to overbear and as a result the nuts will be small. This has not been a problem with 142Q where the nuts have been consistently large and free falling from the burrs. Nut quality was generally very good this year and was literally unaffected by the spring drought.
The following table lists our best selections. It includes Layeroka. The others are all seedling selections of Layeroka. None of them produce much viable pollen and so require other trees as pollinators. Where light soils and good drainage exist, these trees could be a profitable commercial crop. Unlike walnuts, there is very little shrinkage due to drying, and the price for chestnuts has been higher for several years now making it an attractive crop, especially for the premium sized nuts.
|(Ratings: 1 high, 5 low)||1987||1988||1987||1988|
A heartnut orchard of 35 trees was newly established in the spring of 1987 on about 0.4 ha. None of the trees were watered during the spring drought of 1988 and they all survived largely unaffected. Most had a crop of from two to ten more nuts. Growth was good where they averaged from 0.5 m to 1.5 m of new growth. They were cultivated five times through the growing season and one spring application of 15-15-15 fertilizer was applied at about 200 Ib/A. No disease or insect problem was observed and no foliar sprays were applied.
Fourteen cultivars or selections are represented in the planting. They will be evaluated for nut production and nut quality characteristics when the trees become larger.
There are a few larger heartnut trees that are used to produce scion wood as well as some nuts. Fodermaier was our best producer this year, yielding 2000 kg/ha. The Mitchell Hybrid yielded 796 kg/ha of cleaned nuts and a crop of scion wood in the spring. On these trees the moisture loss is less than Persian walnuts in drying, probably about 10%. Our favorite selections, including the two above are Campbell West (CW3) and Campbell East (CW1).
Site #3 - Charles A. Rhora, R.R. #1, Wainfleet, Ontario LOS 1VO
The total area planted to nut trees is now about 20 acres.
Further tests and experiments were carried out in 1988 on the following species: Chinese chestnut, hazelnut (filbert), Carpathian walnut and pine nut. Trees are established for evaluation and selection of superior trees. Tests were conducted on irrigation, fertilization and the use of innoculants to produce better growth and healthier trees.
A nursery has been established with a large quantity of seedlings of chestnuts, heartnuts, Carpathian walnuts, hazelnuts (bush and tree form), and nut pines as well as other species of nuts which show a possible commercial crop here in Ontario.
The chestnut planting is on a sandy loam soil with good drainage. All are seedlings in their fifth year of growth. There were no losses of trees in spite of the long, dry spell. Some of the inferior seedlings were removed and replaced with other seedlings. There was a 95% catkin production and several seedlings look promising. The total crop was 20 pounds which will be used in the nursery. An additional acre of chestnuts was planted out in 1988 as seedlings of the above trees.
The Persian walnut orchard was expanded by one acre this year bringing the total acreage to six acres. This orchard consists of seedlings of a number of sources from Canada, the United States, Europe and Asia. All have proven winter hardy to date. They were planted in a hedgerow style with the intent of selecting the superior ones and eliminating the inferior ones. They average in age from one to six years with no production to date. In addition, there were no insects or diseases noted. In addition, there is a grafted Cobles #2 and a Hansen graft which have produced a crop of nuts each year. From the Cobles #2, seedlings were established and several have produced crops. No pests or diseases were noticed.
One additional acre was added this year, making a four acre hazelnut orchard of approximately 4000 trees. They are growing in a hedgerow style. Inferior seedlings were culled out and replaced with new seedlings. All of the established trees produced catkins with good production. Total crop was 140 pounds which was sold locally at $2.50 to $3.00 per pound.
The seedling heartnut orchard continues to do very well. The trees average four years in age and show good growth of one to two feet. A few trees are producing small crops. No pests or diseases were observed in the orchard. There is one grafted Etter heartnut which has consistently produced crops for the past five years. Some of the seedlings produced from Etter nuts have shown some promise. There was a total crop of 50 pounds of nuts.
The Jeffery pine planting was expanded in 1988 and now consists of over 200 trees. Survival was 98% even with the long, dry spell. Average age of the trees is from three to four years. There was not production to date. An innoculant was added to each tree to induce a better root system, earlier production of seed and faster growth rate. Results will be observed in 1989.
A planting of 150 trees was established in 1988. An innoculant was added again this year. Growth averaged 10 to 15 inches. They show good colour with no winter injury. No pests or diseases were noted.
Site #4 - L.H. Cruttenden, R.R.#1, Lucan, Ontario NOM 2JO
As mentioned in previous reports, Chinese chestnuts did not do well on our clay loam soil and the process of moving the trees onto sandy soil had begun in 1987 with the movement of grafted trees into rows 40 feet apart. During 1988, seedling trees were moved to planting stations in between these 40 boot rows in order to act as pollinators for the grafted trees. In addition, another row of grafted trees was added. Thus, 25 trees were transplanted in 1988, and the size of the Chinese chestnut orchard is now 1.9 acres. All these transplanted trees have survived thus far, though several are not yet well established.
The grafted chestnut trees do not shed their leaves throughout the fall and winter, and this created a problem during an early spring ice storm. All of the leaves were coated in ice, which had to be removed by hand during the storm to prevent serious breakage due to the weight of the ice. Some breakage did occur when the ice could not be removed quickly enough. It was an unusually severe ice storm. Most of the seedling trees suffer from the same problem. It would be a great advantage if an improved cultivar could be selected which sheds its leaves in the fall.
Along with most of Ontario, we experienced an exceptionally dry spring, and a dry, very hot summer. Water was carted to the trees to alleviate the severe moisture stress that was created. This was the second year in a row that a moisture problem existed. In addition to watering the trees, they were mulched with all the grass that could be cut between the rows, in order to conserve moisture. Each tree was given a fairly thick mulch in a four to six foot radius around the bole. Nonetheless, the watering and mulching together came nowhere near to compensating for the lack of rainfall and heat. It was essentially only a life-saving measure, and that it did. No trees were lost due to the drought, though some of the transplanted chestnuts were adversely affected. Growth of new wood varied from only 6 inches up to 24 inches on the well-established chestnut trees. On the 1987 and 1988 transplants, it was less. The older established trees looked impressive through the summer, despite the conditions.
Probably as a further result of the drought, few of the burrs that were produced filled out, though the crop was an improvement on the previous year. Immaturity of the trees was undoubtedly an important factor. Only 46 pounds of nuts were harvested. These were given to various people from Korea, central Europe, and the Phillipines who know chestnuts, for taste and quality testing. They reported that they were good to excellent in quality and taste.
There were no pests or diseases other than a few tree hoppers; but even these were no cause for any concern.
In 1987, walnut trees were established at 40 by 40 foot spacing. In 1988, seedling walnut trees were planted in between these trees, creating a spacing of 20 by 40 feet. Fifty-seven of the eighty trees were planted this spring. The interplanting was not completed due to the hot spring conditions. Having this wide spacing between the rows allowed mowing and raking the grass for mulch to conserve moisture and suppress weeds. All of the trees planted in 1987 survived the first winter. Though there had been some dieback, all grew from above the graft.
There was a late spring frost on the morning of May 26. This was somewhat later than usual and the leaf buds were opened. Although a large proportion of the trees were covered the evening before, there was still some damage to growing points on the trees that were not covered, causing excessive branching thereafter. This kind of late spring frost has been a problem in most years, or until the trees have grown taller than four or five feet.
The walnuts were less affected by the drought than the Chinese chestnuts. Their strong taproot appears to be a very definite advantage in this respect. Generally speaking, the vigour and growth of the walnuts was very satisfactory, considering the dry year. The trees were watered a number of times, so they were never in danger of being lost to drought.
Tree hoppers were a bit of a problem, despite having sprayed with dormant oil in early spring.
An early, exceptionally heavy snowfall on October 12 struck before the trees had begun to lose their leaves. This weighed the trees down heavily and caused a few broken branches. Further damage was prevented by removing the snow by hand from the trees during the storm.
Site #5 - Glenn D. Sandham, R.R. #3, Collingwood, Ontario L9Y 3Z2
On a five acre planting in the Tillsonburg area, Mr. Sandham is comparing seedling nut trees to a selection of grafted trees to determine selections that are suited to his growing area.
The 1988 growing season in the Tillsonburg area was abnormal in both temperature and rainfall. The timing of the weather patterns played a critical role in the growth rate of the trees. June and July were above average in termperature and well below average in rainfall which led to little or no growth. Leaves were burning by late July. Considering the duration of the drought, the mortality rate of the trees was surprisingly low, 6 trees or about 2 percent. The above average rainfall came in August causing a large late flush of growth. Some of the one year old seedling transplants tripled in size after the many and frequent rainstorms in August. As a result, the trees did not harden off completely and winter dieback will probably be fairly extensive in the spring.
SITE #6 - Paul A. Bennett, R.R. #4, Paisley, Ontario NOG 2NO
Thirty-eight New York hybrid seedlings were planted at two years of age in 1984. These produced their first crop of significance in 1988. Yield was 16.8 pounds for the 38 trees, averaging 0.44 pounds per tree. Nut size varied greatly but quality was consistently good. All nuts harvested were marketable had the quantities been larger.
The 35 WHES 301 filbert seedlings planted in the spring of 1987 progressed little if at all in
1988. Ten trees suffered rodent damage unlike our other seedlings, where no damage was
observed. No protective measures had been taken for any of them. New plantings were made of
the following seed sources:
45 WHES 301 seedlings
10 WHES 302 seedlings
400 Grimo 192G seedlings, a Manoka seedling source
200 Grimo 32N seedlings
100 Grimo 206M seedlings, a NY 1329 seedling source
100 NY 104 seedlings
100 NY mixed seedlings
100 Gellatly 502 seedlings
100 Gordon's largest seedlings, a NY seed source
200 Petoka seedlings
200 Grimo 206C seedlings, a NY seedling source
100 NY 110 seedlings
100 Grimo 202D seedlings, a NY seedling source
100 Grimo 202K seedlings, a NY 1329 seedling source
Walnut and Pecan
Our small planting of Carpathian walnuts and northern pecans continues to grow slowly. The walnuts continue to be set back by late spring frosts.
Our planting of Bates, Brock and Calendar heartnuts suffered from late spring frosts, but a handful of blooms managed to survive and produce six nuts. Ten Etter strain heartnut seedlings were established in 1988.
Almond and Korean Pine
Ten CE 3 almond seedlings and one hundred almond seeds were planted. Six thousand Korean pine seeds were planted from a Korean source.
Weather and General Observations
One cold snap of -27C late in March seemed to have damaged some of the filbert catkins that had started to open, but no other appreciable damage was observed. The drought conditions of the spring and summer slowed growth in all trees, and some indications of stress were observed on filbert leaf fringes.
Site #7 - G. Robert Hambleton, R.R. # 2, Concession 6 Rd., Niagara -on-the-Lake, Ontario LOS 1JO
Mr. Hambleton is located near Virgil, Ontario on twenty-two acres of land which varies from fine sandy loam to jeddo clay loam. There is a mixed planting of a variety of fruit and nut trees, much of it now approaching twenty years old. Where he is located, he is midway between the frost protection of the Niagara Escarpment and the moderating effects of Lake Erie. On a number of occasions there has been a large loss of the Persian walnut crop due to bud and catkin injury. Mild spring conditions followed by a cold snap has caused the terminal buds and catkins of some trees to die because they have lost their winter hardiness. Although this is a problem, there is generally a crop of nuts every year.
The table below compares seven of the approximately 140 trees in the Persian walnut planting. Crops have been recorded from the year planted up to 1988, with tree descriptions following. Some discrepancies have occurred due to squirrel predation and hand picking of green walnuts in 1982 that reduced the crop.
In 1981, when all of the trees had a spread less than 20 feet, Tree 3x10 had a crop of 28.85 pounds. At the existing spacing of 40 feet, one acre of 27 trees would produce a crop of 780 pounds. If spaced at 20 feet, one acre of 27 trees would produce a crop of 780 pounds. If spaced at 20 feet, the crop would be 3145 pounds. In 1987, this same tree had 72.47 pounds. At 40 foot spacing, 27 trees would give a crop of 1957 pounds.
The Hansen trees and its seedling (Tree 9x10) grow much less and is more dwarfed than the HW1 and W2 seedlings. Because of the heavy crop of nuts on the Hansen trees (Tree 5x14 and Tree 9 x 14) in 1987, there was a lot of winterkill on the twigs, greatly reducing the 1988 crop. Most of the other trees have not shown this tendency.
|Persian Walnut Crop Per Tree - In Pounds Except Where Noted|
|Year||HW1 SDLG||HW1 SDLG||W2 SDLG||Hansen SG||Hansen GR||Hansen GR||W2 SDLG|
|1976||6 nuts||2 nuts||27 nuts|
|1977||21 nuts||20 nuts||3 quarts|
Bacterial Blight on Juglans Regia Trees and Crops
All of the Persian walnut trees in the Hambleton planting are interplanted with fruit trees. The fruit trees are very sensitive to the copper sprays needed to control the bacterial blight of walnuts. This makes it impossible to spray the walnut trees. It was hoped that by driving copper nails into the trees that there would be enough copper intake to effect a control. The 1987 study did not show any correlation between blight resistance and the presence of measured elements.
This year a few more copper nails were driven into the two limbs that were experimented on last year. The old nails were taken out and driven in on an angle, so that the ends of the nails didn't go into the hardwood. The new nails were also driven in the same way.
This year was very dry and the incidence of blight was greatly reduced. Rainfall is the medium needed by the blight organism to spread to new sites. Nuts were harvested from trees this year that other years blighted so badly the crop was almost wiped out. Even though there was a lessened occurrence of blight, there was not enough improvement noted in the trees containing the copper nails to suggest that it was an effective control for bacterial blight.
Walnuts need good locations that will not bring the pistillate flowers and catkins out of dormancy too early. When dormant, the buds and catkins will take quite low temperatures. Once they move, they lose their hardiness. Some trees need longer periods of warm weather to cause them to break dormancy. Walnut trees with the proper characteristics should be viable commercially.
Provided by SONG. Feel free to copy with a credit.