Note to readers, attached is the complete final report for FNE95-106.
Leafhoppers are a foliar insect pest of apples throughout apple growing region of the Hudson Valley of New York state, regions of Wayne Co. in Western NY and across the Southern tier of New England. They have traditionally been controlled by apple producers through the use of seasonal pesticide applications aimed at the more susceptible nymphal stage of development. The mid to late season applications have become increasingly undesirable in light of present agricultural and environmental trends. The impact they may have on late season predator populations, the moderate to high toxicity levels and potential exposure risks to applicators, the need to reduce overall pesticide output and pesticide residual on fruit are some of the factors contributing to the need for alternatives to late season applications. Preliminary trials conducted in 1994 at the NYSAES in Highland, New York and at Breezy Hill Orchard have shown substantial reductions of the egg laying adults of two primary leafhopper species and subsequent reduction of 2nd and 3rd generation nymphs when carbaryl was used in a single thinning application shortly after petal fall on apple. The experimental results from this 1995 trial showed again the effectiveness of thinning applications of carbaryl by controlling early season populations of white apple and rose leafhopper nymphs and adults. The experiments conducted at the Hudson Valley lab and at Breezy Hill Orchard using Rhone-Pouloncs new formulation of carbryl, Sevin XLR, clearly demonstrated the effectiveness of a single application on the reduction of two of the three species comprising the Hudson Valley leafhopper complex. Data gathered on photosynthesis leaf measurements have shown a reduction of leaf photosynthesis as leafhopper feeding increased but only as the most severe leaf rating were the reductions substantial. This work and that of other university research entomologists will allow apple producers to maintain moderate levels of leafhopper feeding without concern to tree physiology and fruit quality.