Impact of Infestation with Eriosoma lanigerum of Three Apple Cultivars on The Nitrogen and Carbohydrates Content and The Efficacy of The Parasitoide Aphelinus mali in Reducing the Infestation rate in Latakia Governorate, Syria.

Abstract

Eriosoma lanigerum is considered a serious pest that attacks the apple canopy and its roots. It has a negative effect on the world apple fruits production. E. lanigerum feeds on sap and causes wrinkling and twisting of the young shoots and it reduces tree vitality. This research aimed to estimate the susceptibility of two apple cultivars Royal Gala and Granny Smith and the rootstock Malus sylvestris^” to E. lanigerum infestation and investigate the effect of the parasitoid A. mali in alleviating the E. lanigerum infestation. The study was conducted on the apple cvs. Royal Gala and Granny Smith grafted on the rootstock Malus sylvestris^” at an orchard in Kasab village, Agriculture Directorate, Latakia Province during the 2020-2021 growing seasons. Trees were infested in June, and the pest severity and aerial infestation were estimated four months after the initial infestation. The parasitism rate was also evaluated in July, August and September. The apple cv. Granny smith showed the highest infestation severity (63.45 %) compared with the control (42.74 %). The rootstock ^” Malus sylvestris^” had the least infestation severity (43.77 %) compared to the control (25.54 %). Cultivar Granny Smith was the most susceptible to infestation (69.16 %) compared with the control (61.01%). To the contrary, the use of the root stock Malus sylvestris gave the lowest aerial infestation (60.00%) compared with the control (43.77%). Parasitism reduced the aerial infestation rate of the cv. Royal Gala by 79.21% compared to 69.57% for the control. Using the rootstock ^” Malus sylvestris^” in apple orchards can alleviate the E. lanigerum infestation due to its resistance of E. lanigerum. In addition, the release of the parasitoid A. mali can be an added component for Eriosoma lanigerum control.

Keywords:

Eriosoma lanigerum infestation, parasitism, Eriosoma lanigerum, Aphelinus mali.