Population fluctuations of grape leafhopper, Arboridia kermanshah (Hemiptera: Cicadellidae), under natural conditions of Kermanshah grapes

Grape leafhopper, Arboridia kermanshah, is an important pest species in Iranian vineyards. Adults and nymphs cause damages by piercing the leaf tissues and sucking the intracellular contents. This study was focused on the biology of grape leafhopper in Kermanshah Province. Grape leaves was used as sampling units to estimate eggs and nymphs populations and sticky yellow traps was used to estimate adult’s population. A vineyard was sampled weekly, during growing seasons in 2017 and 2018. Our findings indicated that the leafhopper has three generations per year in Kermanshah. Overwintering of adults happened in the remnants of sheds and under grape barks. Population dynamics of A. kermanshah was studied in relation to temperature and relative humidity. Population dynamics of grape leafhopper was significantly and positively related to temperature in all biological instars of pest in 2017 except the second and the third nymphal instars. Population fluctution was significantly related to relative humidity only for the fifth nymphal instar in 2017. There were significant and positive relationship between temperature and population dynamics of eggs, and the fifth nymphal instars in 2018. Relative humidity changes had also significant relation with all stages except the fourth and the fifth instar nymphs. The density of parasitized eggs by Oligosita pallida Kryger were 93.24±1.1% and 89.74±4.9% in the first and second sampling year, respectively. Hence, the egg parasitoids were very effective in the last generation, therefor, the chemical control for this pest is not recommended