We subjected grapevines to mid-season irrigation deficits of 25% or 50% of full irrigation, and found grape leafhopper nymphal density consistently lower on vines subjected to water stress, although we found no difference between the two deficit treatments. Three possibilities exist to explain the response: 1) lower oviposition rate 2) higher egg mortality or 3) higher nymphal mortality. We found lower densities of eggs on deficit irrigated vines, but found no difference in egg survivorship. We established a greenhouse study to look at nymphal mortality, caging 10 nymphs/leaf on 10 deficit and control vines. We also measured cuticle thickness as a possible mechanism for increased nymphal mortality.
Species 1: Homoptera Cicadellidae Erythroneura elegantula (Grape leafhopper)
Keywords: grapes, water
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