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A new biopesticide has been commercially available to apple growers since 2001 in the kaolin clay-based product. This material meets Federal standards for use in organic crop production as a potential replacement for some insecticides that manage key apple insect pests. Initial research indicated that kaolin might have non-target impacts such a reduction in canopy temperature. However, most of the research on non-target effects, such as impacts on fruit quality, has been conducted in warmer, semi-arid environments. These potential impacts may not be beneficial in cooler orchard environments. The objectives of this 3-year study are to determine potential non-target effects of Surround WP application in the relatively cool and moist climate of the Northeast on `McIntosh'/M.26 apple tree productivity, and fruit quality. In 2001, preliminary data were collected and are included in these results. Treatments include: (1) Surround beginning at green tip plus fungicides; (2) Surround beginning at green tip without fungicides; (3) Surround beginning at petal fall plus fungicides; (4) IPM; and (5) Nontreated control. In 2001, the control treatment received fungicides. For 2002 and beyond, the protocol was amended to remove fungicides treatments. Data analysis indicate significant differences in treatments for several of the variables measured (fruit weight, percent drop, yield efficiency, starch index, soluble solids, fruit packout, and insect and disease damage). However, some of these differences might be due to the high incidence of scab in the treatments that received no fungicides and not due to the effect of Surround. There were no significant differences in other variables measured such as thinning, fruit color, and spur diameter.

Surround WP, a kaolin clay-based biopesticide product, is a potential alternative to some organophosphates used in apple orchards for the management of pests, such as codling moth. In addition, Surround has been reported to have important nontarget horticultural impacts because of its effect on canopy temperature reduction. The label for use of Surround states: “When applied at recommended rates and frequencies, benefits such as increased plant vigor and improved yields may occur in certain apple cultivars.” However, most of the research on nontarget effects has been conducted in warmer, semiarid environments. The objectives of this 3-year (2002–04) interdisciplinary research project were to determine potential nontarget effects of Surround WP application on apple tree vigor, productivity, and fruit quality in the relatively cool and moist climate of the Northeast. The research was conducted at the UVM Horticultural Research Center in South Burlington, Vt., on `McIntosh'/M26 trees. The experiment used a completely randomized design with five treatments replicated six times. Each replicate consisted of single tree plots. Treatments included: 1) Surround beginning at green tip plus fungicides; 2) Surround beginning at green tip without fungicides; 3) Surround beginning at petal fall plus fungicides; 4) standard IPM; and 5) nontreated control. Results indicate no significant differences among treatments 1, 3, and 4 (treatments that included fungicide applications) in vegetative shoot length, spur characteristics, blossom number, fruit weight, firmness, soluble solids, and fruit calcium levels. Trees treated with Surround had significantly lower yield efficiencies in 2003 and 2004 than trees under IPM treatment.