Scaffolds 01 index

(David Combs, dbc10@nysaes.cornell.edu, Harvey Reissig, whr1@nysaes.cornell.edu, and Art Agnello, ama4@nysaes.cornell.edu, Entomology, Geneva)

As the concern grows over what materials and how much of them are being used in commercial tree fruit production, so does the tireless effort of manufacturers attempting to find new materials that are "lower risk". The issues brought about by the FQPA, along with resistance problems from various pests, have gotten agricultural chemical companies scrambling to find alternative materials that will not only satisfy the concerns over potential environmental and health problems, but also give acceptable pest control as well. As you are already probably aware, there is an influx of new materials that have flooded the market, and also those that are currently pending registration. Along with this push for safer insecticides, the public and growers alike have shown interest in organically produced fruit. Several growers throughout New York State have already started to plant new blocks with an organic certification in mind.

Trials conducted at the Geneva Experiment Station during the 2000 growing season examined some of these organic materials in a season-long spray program to test whether these materials could have a positive bearing on the fruit industry in New York. This experiment was designed to give somewhat of an overview of what the materials were capable of against the predominant pests of the region. The treatments consisted of weekly sprays from mid-May through late August of Surround WP, a hydrophobic clay film that creates a barrier around the fruit and foliage; the highly refined horticultural mineral oil Orchex 796 (sold in the east as Omni Supreme); and a new botanical material called Aza-Direct (azadirachtin, a neem product). The standard OP, Imidan 70WP, was applied on a 14-day schedule as well, for comparison.

Apples that have been treated with Surround

As you may have already assumed, the Imidan treatment gave the best overall results at harvest. However, there were some results from the organic treatments that were not anticipated. Some of these materials did well against certain pests: Surround on plum curculio; Orchex and Aza-Direct on leafminers; and all treatments on internal worms such as codling moth and oriental fruit moth. After further testing in 2001, we may be able to make recommendations for these chemicals. However, I do not suggest running out and planting an organic block right away. The industry is not financially ready for mass-produced organic crops, especially on the part of the grower.

Some other organic tests were conducted in Niagara County in Jim Bittner's (Singer Farms) orchards in a variety of different arenas. Using an airblast sprayer to apply Surround WP to one treatment and Dipel plus Orchex to another yielded interesting results. Damage from the major pests was not adequately controlled in these programs, although again the Surround significantly lowered plum curculio damage. In the case of other pests, the damage was actually higher in the treated plots. However, in all fairness to the test and materials, the Surround treatment consisted of only five applications and the Bt and oil program, four. In addition, the applications were not started until after fruit set, because of logistical problems. It is also important to note that no other pesticide was used on these trees.

Mating disruption with the use of pheromones was also conducted in another organic block on Jim's farm. Automated microsprayer dispensers containing a mixture of synthetic pheromones were distributed throughout an orchard. The microsprayers were effective in disrupting the chemical communications of codling moth, obliquebanded leafroller, and oriental fruit moth; however, the target species were not completely controlled. The damage found was less than in an undisrupted check orchard, but other problematic pests caused considerable damage.

As a final experiment, whole-tree exclusion cages were used to try to simply keep pests from getting to the tree. A local tent maker in Geneva manufactured bags from four different netting materials with different mesh sizes. The bags were placed on the trees in late May after the pollination period, and left on until harvest. No further sprays were applied for the remainder of the season. Although this method seemed to produce more clean fruit than the other on-farm trials, the cost and labor intensity limits the practicality of this technique. Some insects (such as leafrollers) were actually trapped inside the bags and were able to damage fruit throughout the season; also, a reduction of light penetration into the tree canopy caused reduced coloring on the fruit.

Whole-tree exclusion bags on large trees

These trials are only a stepping stone towards the production of organically produced fruit. With some fine-tuning and further testing, seasonal programs that incorporate all or some of these methods applied at specific timings for the niche where they are best suited may be a possibility. Consumers are probably already somewhat accustomed to seeing a less than perfect apple come from organic production, but very few if any are sold on the fresh market. With these materials and techniques, combined with cultural practices, that may change in the future.

It is important to note that this is not yet a recommendation for the planting of organic orchards. The blocks that were used in this study were converted from conventional production in the mid-1990's to fit a niche of juice and dried slices. However, very small changes in the current economic balance would make this system both impractical and unrealistic.

Chem News 4.2