Control of Arthropods on Apple Selections with Scab (Ascomycetes: Mycophaerellacea) and European

ABSTRACT Use of pest and disease resistant cultivars in pest management is an alternative to commercial apple production that depends on use of chemical pesticides. Over a 3-yr period, we produced fruit that were 86 % free of damage by key pests using selections with apple scab, Venturia inaequalis (eke.) Wint, and European red mite, Panonychus ulmi (Koch) resistance and three critically timed sprays of either fenvalerate or phosmet. Although we did not use one, a fungicide may be needed to produce fruit that would grade well if summer diseases, Gloedes pomogena (Schw.) Colby and Leptothyrium pomi (Mont. & Fr.) Saccoare a problem. The management program for these resistant selections produced a crop of undamaged fruit comparable with one that would be produced with a calendar-based spray program on commercially grown cultivars susceptible to pests and diseases. The cost of a program including eight sprays of insecticides, fungicides, and acaricides recommended in Indiana for apple production is $1,387.48 per season per hectare for cultivars not resistant to pests. This cost was reduced to $84.90 with phosmet or $240.00 per hectare with fen valerate for the season when resistant selections were used. Summer disease control was not considered in our investigation but, if needed, two sprays of fungicide would cost $77.40 per season pe