Efficacy of Certain Insecticides and Mineral Oil in Controlling Aphid, Aphis gossypii Glov. and Papaya Ringspot Virus in Squash at Kafr El-Sheikh Governorate

Abstract

Melon aphid, Aphis gossypii Glov. is one of the most important insect pests infesting squash plants causing severe damage and is responsible for transmitting plant viruses. Among these viruses is, Papaya ringspot virus-W (PRSV-W) which, is a virus with the highest economic impact on cucurbits production. A two-year field experiment (2019 and 2020) was conducted at Kafr El-Sheikh Governorate to evaluate efficacy of three insecticides: Chess 50 % WG (pymetrozine), Teppeki 50 % WG (flonicamid) and Confidor 20 % (imidacloprid) as well as mineral oil (KZ 95 % EC) against aphids and spread of PRSV. The treatments were arranged in a randomised complete block design with three replications. During two seasons, tested compounds significantly reduced population of aphid vector, as well as the incidences of PRSV infections and increased fruit yield compared to control. Mineral oil had little effect on aphid populations but it was the best choice to reduce PRSV spread. Imidacloprid was the most effective insecticide against aphids but it was the least in reducing PRSVspread. Both antifeedant insecticides, flonicamid and pymetrozine significantly reduced populations of aphid and incidences of PRSV but they significantly increased fruit yield. Population of aphid was positively correlated with incidence of PRSV. Fruit yield was also negatively correlated with incidence of PRSV and aphid population. Overall, this work showed that it is possible to increase protection of cucurbits fields against PRSV and other non-persistent viruses by incorporating chemicals with different modes of action such as flonicamid, pymetrozine, and mineral oils.