Testing the efficacy of single applications of five insecticides against<i>Scaphoideus titanus</i>on common grapevines

Abstract

The appearance of the Flavescence Dorée phytoplasma and the possibility of its rapid spread by its vector, the American Grapevine Leafhopper (Scaphoideus titanus Ball) (AGVL), represent a serious threat to viticulture production in Slovenia and elsewhere in Europe. Insecticide treatment represents one of major means of reducing the abundance of AGVL in wine-growing areas. In the period from 2010 to 2011, five insecticides against AGVL were tested, and the efficacy of the substances was calculated according to the number of nymphs (at 2, 7, 14 and 21 d after application), which were counted on the grapevine leaves. In both years, the highest cumulative efficacy (96–97% or 0.01 nymphs/leaf) was confirmed for thiamethoxam, whereas chlorpyrifos-methyl showed a very high cumulative efficacy (87–89% or 0.01–0.02 nymphs/leaf). In 2010, indoxacarb exhibited only a 43% (0.09 nymphs/leaf) cumulative efficacy; however, its substitute in 2011, chlorpyrifos, was more effective (73% or 0.05 nymphs/leaf). A single application of pyrethrin demonstrated only 45–61% (0.05–0.09 nymphs/leaf) efficacy. Based on the results of our research, we recommend the use of thiamethoxam and chlorpyrifos-methyl against AGVL.