Henry W. Hogmire

Assessment of an Alternative IPM Program for the Production of Apples for Processing

Conventional and alternative integrated pest management (IPM) programs for managing arthropods and diseases affecting processing apple production were compared over 4 years. The effects of the two programs on populations of pest and beneficial insects, and on disease incidence and severity, were evaluated in the field and laboratory and at a commercial fruit processing plant by federal inspectors. The economic implications of the alternative management program were assessed by examining its relative costs and benefits compared with conventional management. In the alternative program, arthropods were managed with oil and Bacillus thuringiensis (Bt), and early-season diseases were managed with fungicides. Calcium chloride was used to suppress rot diseases. The alternative plots showed lower levels of indirect pests (aphids, leaf-hoppers, and mites) and increased numbers of arthropod natural enemies. On harvested fruit, there was significantly more injury in the alternative plots from codling moth or oriental fruit moth, plum curculio, and apple maggot. Levels of foliar diseases were similar between treatments; however, fruit from the alternative program exhibited significantly more sooty blotch, flyspeck, and rots. At the commercial processor, levels of cull fruit were higher for the alternative program in 2 of the 3 years with harvestable yield. Loads of fruit that were not acceptable for processing were due mostly to internal worms and worm damage. Incidence of decay was within the quality limits set by the processor, except for one conventional sample, in which decay exceeded 5%. Of the 36 loads of fruit that were examined from each program, 4 and 13 loads were rejected from the conventional and alternative programs, respectively. Net present value comparisons were dependent upon how rejected loads were valued. At cider prices for rejected loads, net returns were similar between programs. When rejected loads were valued at a complete loss, conventional net present value was over 140% higher than the alternative program. Among cultivars, Golden Delicious was most profitable and York was least profitable.

Growth of apple trees, nitrate mobility and pest populations following a corn versus fescue crop rotation

We compared conventional and alternative systems for the establishment of apple trees on a replicated, whole-orchard scale. The alternative system consisted of a K-31 fescue sod rotation followed by planting of trees directly into sod that had been kitted with herbicide. The conventional system consisted of a standard corn rotation, accompanied by application of fertilizer and nematicide. Orchard floor management in the three years following tree planting was based on the use of both pre-and post-emergence herbicides in the conventional system and only contact herbicide in the alternative system. The study documented tree growth, pest incidence, and nitrate mobility in the two systems. The alternative system compared favorably with the conventional system for the growth and establishment of four apple cultivars. Many advantages accompanied the killed sod system, including less subsurface leaching ofnitrate-N and lower costs (largely from decreased herbicide use). The alternative system provided an economical alternative to the problem of soil organic matter depletion in conventional orchard soils without requiring increased use of commercial fertilizers. Grower concerns regarding increased potential for vole damage and poor initial tree growth were unsubstantiated.