Biological Efficacy of Botanical Insecticides in the Control of Green Apple Aphid (Aphis pomi De Geer)

Abstract: The effects of the botanical insecticides pyrethrin (Pyros®), rotenone (Rotenone®) and pyrethrin + rotenone (ShowTop) were monitored in two apple orchards planted with cvs. Granny Smith and Kožara. The trial was set up according to the EPPO PP1/21(2) Protocol. The insecticides were applied in each of four rows. Four leaves from each tree were designated as samples for monitoring the population pressure of Aphis pomi De Geer. The insecticides were applied in June by spray drift and atomiser. The temperature was 23°C and relative air humidity 63%. The pest population pressure was checked immediately before the treatment and on the 1st, 2nd, 3rd and 7th day after treatment (DAT). The highest efficacious insecticide was Pyros® (83.2%) on 1 DAT followed by ShowTop (82.8%), whereas Rotenone® was the least effective (67.1%) at controlling A. pomi. Rotenone® was most effective on 2 DAT (72.1%), with subsequent inspections showing a decrease in efficacy (67.3% and 44.7%). For Pyros®, further inspection on 2 and 3 DAT registered a decline in efficacy to 72-73%, whereas on 7 DAT it reduced to 55.7%. The inspection on 2 DAT reported the highest efficacy of ShowTop (84%) and a further decline to 76.4% and 69.5% on 3 DAT and 7 DAT, respectively.