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Rate of spread of citrus blight reduced when sharpshooter leafhoppers (Homoptera: Cicadellidae) are controlled

Adlerz, W.C., Bistline, F.W., Russo, L.W., Hopkins, D.L.
Journal of economic entomology 1989 v.82 no.6 pp. 1733-1737
bacteria, Citrus sinensis, blight, disease vectors, Hemiptera, insect control, insect traps, chlorpyrifos, dicofol, monitoring, ethion, Xylella fastidiosa, Florida
Insect traps were used to monitor populations of sharpshooter leafhopper vectors, Oncometopia nigricans (Walker) and Homalodisca coagulata (Say), of Xylella fastidiosa Wells et al., a xylem-limited bacterium, in four 11-ha plots of 'Valencia' oranges, Citrus sinensis (L.) Osb., and four 6-ha plots of 'Pineapple' oranges in a grove infected with citrus blight. When trap catches indicated that leafhopper populations were increasing, supplemental applications of insecticides were applied to half of the plots. One to three extra applications of insecticides per year were made to maintain significant differences in leaf-hopper populations between the routine care plots and the supplemental insecticide plots. Linear regression equations, with percentage citrus blight as a function of time in months, were fitted to the data for the supplemental insecticide and routine care plots. In the 'Valenica' plots, the slope of the regression line for the routine care plot was significantly greater than the slope for the supplemental insecticide plots; therefore, the rate of spread of blight was reduced significantly where supplemental insecticide applications were made. In 'Pineapple' plots, the trend was similar but the difference in slope was not statistically significant.