Abundance and Consumption Rate of Glassy-Winged Sharpshooter (Hemiptera: Cicadellidae) on Peaches and Plums
Homalodisca vitripennis (Germar), the glassy-winged sharpshooter, is a primary vector of phony peach and plum leaf scald diseases caused by Xylella fastidiosa Wells et al. A survey of H. vitripennis on peach [Prunus persica (L.) Batsch] varieties established that leafhopper abundances varied from 0-13 per tree. Prunus persica cvs. Flordaking and June Gold and Prunus salicina Lindl. (cvs. Methley and Santa Rosa) were then budded on each of 3 P. persica rootstocks (cvs. Aldrighi, Lovell and Nemaguard). Leafhopper abundance was monitored on each of the two scions budded on each rootstock and on non budded rootstocks over a 2-yr period. The genotypes were container-grown in Year 1 and were planted in the field in Year 2. For both years leathopper abundance was greatest during early June and on Methley and Santa Rosa cultivars compared with the peach genotypes. The feeding rates of leafhoppers were substantially higher on plum scions than on peach scions, and nocturnal feeding rates were often higher than daytime feeding rates. Mean leafhopper feeding rates were correlated with leafhopper abundance on Prunus genotypes from 3-8 June in a quadratic manner (F = 53.8; df = 2,12; R(2) = 0.90; P < 0.0001); the mean nighttime feeding rate was best correlated linearly to mean cumulative leafhopper abundance (F = 446.9; df = 1,13; R(2) = 0.972; P < 0.0001).