Progress 04/01/02 to 03/31/05
Outputs
We tested organically approved materials 0.5% cytokinin, a class of plant hormone for chemical thinning. Applications were made at 50 and 75 ppm at petal fall and at 10mm fruit size. The applications of cytokinin had no effect on crop load or fruit size in either study. It appears unlikely that this cytokinin will be an effective fruit-thinning agent. Efforts to control plum curculio with kaolin were only moderately effective. Better results were achieved with cultural methods, such as picking up dropped apples. We conducted field trials using organic products for control of apple scab, sooty blotch and flyspeck. Calcium soap (CaC8) and CaC8 with sulfur showed very poor efficacy in the control of all 3 diseases. There were no significant differences between the calcium soap products and untreated fruit. In our large-scale organic apple plantings, attempts to control weeds with organic herbicides proved unsuccessful. The combination of weed mats and tree mulch has
provided favorable weed control, which has allowed the organic trees to improve their growth rates, although they still lag behind the conventional trees. The only major weed not controlled is thistle. Applications of neem to young trees have proven to be a fairly successful method for avoiding injury from Japanese beetles. 2003 was the first year with commercial levels of fruit production in the Gold Rush plots. Conventional trees averaged 62.2 fruit per tree, totaling 22.3 lb of fruit per tree, for an average fruit weight of 0.36 lb per fruit. The organic trees averaged 3.0 fruit, 1.0 lb, and 0.33 lb per fruit. The values from the conventional trees were significantly higher (P = 0.05; LSD) than from the organic trees for each of the three variables. These differences are the result of poor weed control early in the tree growth. Although yields in both treatments were relatively low, harvest data in 2004 showed significantly higher yields in the conventional Pristine trees. In the
GoldRush apples, conventional trees averaged 111.7 fruit per tree, 36.1 lb of fruit per tree and an average fruit weight of 0.33 lb compared to 52.7 fruit, 16.2 lb, and an average fruit weight of 0.31 lb in the organic trees. All variables were significantly different (P=0.05, LSD). 2005 was the first year that attempts were made to produce quality fruit. In the Pristine plots, conventional trees averaged 28.4 total fruit per tree and 9.9 lb of fruit per tree compared to 4.9 fruit and 9.9 lb in the organic trees. The conventional trees averaged a significantly higher cull rate than the organic trees, 64.5% to 55.0%. The major factors resulting in culls for the conventional trees were cracking and insects, primarily Japanese beetles and plum curculio. The primary cull factors for the organic trees were small size, poor shape and insects, primarily plum curculio. Culls due to disease were significantly higher in the conventional trees than in the organic trees. Fruit size was higher in
conventional trees but among marketable fruit, organic trees produced larger fruit. This was largely because the larger conventional fruit cracked and were rejected as culls. The 2005 GoldRush harvest has not yet occurred.
Impacts
These studies have shown that apples can be produced organically in the Midwest. An important consideration at the beginning of the process is to select trees that are resistant to apple scab. This decision will eliminate most of the disease concerns. Early in the establishment of an organic orchard, weed control is very important. Failure to control weeds will result in poor tree growth and a delay in fruit production. Because it takes about 4 years to get trees into production, organic growers may want to consider using synthetic herbicides to get their trees established. There would still be plenty of time (4 years) to achieve organic certification before fruit would be harvested. Hand thinning appears to be the only viable method of thinning organic apples. Insect control can be achieved using a combination of cultural practices and several organically approved insecticides. The results of this study have not yet been analyzed for economic viability, but it appears
that it is feasisble to grow apples organically in the Midwest with a reasonable amount of inputs.
Publications
- No publications reported this period
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Progress 10/01/03 to 09/29/04
Outputs
In an attempt to use organically approved materials for chemical thinning, we tested organic nutrient formulation containing 0.5% cytokinin, a class of plant hormone. Two studies were conducted on Golden Delicious trees, one semi-dwarf and one on larger trees. Applications were made at 50 and 75 ppm at petal fall and at 10mm fruit size. The applications of cytokinin had no effect on crop load or fruit size in either study. It appears unlikely that this cytokinin will be an effective fruit-thinning agent. Efforts to control plum curculio with kaolin were only moderately effective. Better results were achieved with cultural methods, such as picking up dropped apples. We conducted field trials using two new 'organic' products for the control of apple scab and sooty blotch and flyspeck. The two new products were calcium soap (CaC8) and CaC8 with sulfur. Both CaC8 and CaC8 with sulfur showed very poor efficacy in the control of apple scab and sooty blotch and flyspeck.
There was no significant difference between the calcium soap products versus the control treatments. Our large-scale organic apple plantings have begun to produce significant amounts of fruit. Attempts to control weeds with organic herbicides proved unsuccessful. The combination of weed mats and tree mulch has provided favorable weed control, which has allowed the organic trees to improve their growth rates, although they still lag behind the conventional trees. The only major weed not controlled is thistle. Applications of neem to young trees have proven to be a successful method for avoiding injury from Japanese beetles. It appears that the neem acts as a repellent rather than as a toxicant. In 2003, a single application of neem kept the beetles off the trees for the entire season. 2003 was the first year with commercial levels of fruit production in the Gold Rush plots. Conventional trees averaged 62.2 fruit per tree, totaling 22.3 pounds of fruit per tree, for an average fruit
weight of 0.36 pounds per fruit. The organic trees averaged 3.0 fruit per tree, totaling 0.99 pounds of fruit per tree, for an average of 0.33 pounds per fruit. The values from the conventional trees were significantly higher (P = 0.05; LSD) than from the organic trees for each of the three variables. Again, these differences are most likely the result of poor weed control early in the growth of the trees. The location of our organic orchard has proven to be very favorable for avoiding insect control. Three codling moth pheromone traps were maintained during 2003 and 2004, with almost no moths captured in the traps and no codling moth damage observed at harvest. Harvest data in 2004 showed significantly higher yields in the conventional Pristine trees Harvest of the Gold Rush apples has not occurred.
Impacts
As this study continues, information will be generated that will determine the feasibility of growing apples organically in the Midwest. The result may be that growers do not attempt an unprofitable enterprise, or we may provide growers with the tools they need to successfully grow apples organically.
Publications
- No publications reported this period
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Progress 10/01/02 to 09/30/03
Outputs
Studies continued on the various components of organic apple production during 2002-3. During 2002, we tested an organic nutrient formulation containing 0.5% cytokinin, a class of plant hormone. It was theorized that this natural cytokinin could be used to thin apples because one of the synthetic thinning agents is also a cytokinin. Two studies were conducted on Golden Delicious trees, one semi-dwarf and one on larger trees. Applications were made at 50 and 75 ppm at petal fall and at 10mm fruit size. The applications of cytokinin had no effect or crop load or fruit size in either study. It appears unlikely that this cytokinin will be an effective fruit-thinning agent. Efforts to control plum curculio with kaolin were only moderately effective. Better results were achieved with cultural methods, such as picking up dropped apples and intercepting some of the migrating plum curculios with traps or sticky bands on the tree trunks. Studies of the migratory activities of
plum curculios into the orchard in early spring were initiated in 2003. Adult movement was measured with windowpane type interception traps, as well as pyramid traps. Catches in both traps were relatively low. Modifications will be made in the studies for 2004. Efforts to evaluate organic methods of controlling codling moths were unsuccessful because of the lack on infestation in the plots. Apple maggot control using attract and kill baits will be continued in 2004 in cooperation with the USDA laboratory in Peoria. Organic disease management studies were continued in 2003 but data have not been collected yet. Our large-scale organic apple plantings have begun to produce significant amounts of fruit. Initial yields were significantly higher in the conventional plots than in the organic plots. These differences are primarily the result of poor weed control during the first two years after planting. Attempts to control weeds with organic herbicides proved unsuccessful. In spring 2002,
weed mats were placed along each side of each organic row and covered with tree mulch. This combination has provided favorable weed control, which has allowed the organic trees to improve their growth rates, although they still lag behind the conventional trees. The only major weed not controlled is thistle. Attempts to control thistle with flaming were not successful in the long term. Applications of neem to young trees have proven to be a successful method for avoiding injury from Japanese beetles. It appears that the neem acts as a repellent rather than as a toxicant. In 2003, a single application of neem kept the beetles off the trees for the entire season. The location of our organic orchard has proven to be very favorable for avoiding insect control. Three codling moth pheromone traps were maintained during 2003, with only a single moth captured all season. No apples in the study were infested with codling moths.
Impacts
As this study continues, information will be generated that will determine the feasibility of growing apples organically in the Midwest. The result may be that growers do not attempt an unprofitable enterprise, or we may provide growers with the tools they need to successfully grow apples organically.
Publications
- No publications reported this period
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Progress 10/01/01 to 09/30/02
Outputs
Plots to evaluate organic controls for apple maggots were established at the Horticultural Research Farm, West Lafayette, Indiana. Individual plots were three consecutive trees. The study was arranged in a randomized complete block design with four replications. Imidan treatments were applied using a tractor-mounted PTO driven sprayer with a handgun nozzle. Spray treatments were applied until runoff. Eight applications of Imidan at a rate of 4 lb/acre were made at 14-day intervals. Other treatments included either one or four sticky spheres per tree, and attract and kill spheres. Red sticky spheres were coated with Tanglefoot and placed in trees in mid June. Two weeks later, bait attractants were placed next to each sticky trap. The attract and kill treatment consisted of a red plastic sphere identical to the sticky spheres, with no Tanglefoot. Each sphere was sanded so that the paint mixture would stick. Each ball was coated three times with a mixture of red paint,
imidacloprid (Provado 1.6F), and sugar. One attract and kill sphere was hung per tree. At harvest, 25 apples from each tree were inspected for the presence of apple maggot damage. Apple maggot damage was relatively light in the plots. There were few significant differences between treatment means. The only apparent trend was that trees with sticky spheres tended to have more apple maggot damage than trees without sticky spheres, with trees with 4 spheres resulting in significantly more damage than trees without spheres. Orthogonal comparisons showed that the two treatments with sticky traps had significantly more damage than the other three treatments. Plots to evaluate organic controls for codling moths were established at the Horticultural Research Farm. Individual plots were five consecutive trees. The study was arranged in a randomized complete block design with five replications. Imidan treatments were applied as described previously. Surround and Sunspray UFO treatments were
applied with an airblast sprayer at a spray volume of 100 gallons/acre. At harvest, 25 apples from each tree, or a total of 625 apples per treatment, were inspected for the presence of codling moth damage. The organic treatments did not result in levels of codling moth damage that were significantly lower than in the untreated control. The Imidan treated trees had lower levels of codling moth damage than the untreated control and both of the organic treatments.Studies to evaluate sulfur and copper for organic disease control were established in a block of scab free apples (RedFree) at the Horticultural Research Farm. Sulfur and copper treatments were compared with a standard fungicide program. However, disease pressure was extremely light and no differences in disease incidence were observed. Large plots to compare organic and conventional management systems were maintained. Weeds in the organic plots were managed with weed mats and bark mulch. One of the varieties planted should have
considerable fruit present in 2003.
Impacts
Although only one year's data has been collected, it is hoped that the results of these studies will allow organic apple growers to manage insect and disease pests with only organically certified products and techniques.
Publications
- No publications reported this period
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