Identification of some fungal species causing powdery mildew diseases in the Syrian coastal region, and investigation of the mycophagous insect Psyllobora vigintiduopunctata associated with them.

Abstract

This study included a survey of some powdery mildew fungal species in the Syrian coast, along with a survey of the spread of the ladybird insect, Psyllobora vigintiduopunctata, that feeds on them, and testing the laboratory efficiency of this insect feeding on the fungus Podosphaera fuliginea, which causes okra powdery mildew disease. The area covered with powdery mildew on which different stages of the insect fed was determined, and the female’s fertility was assessed. The results obtained showed the presence of 13 powdery mildew fungal species belonging to six genera, parasitizing on 24 plant hosts. These hosts varied among different plant families, including herbaceous plants, cultivated crops, ornamental plants, fruit trees, and forest trees. P. vigintiduopunctata was recorded in most of the studied areas, naturally feeding on powdery mildew fungi. Results obtained showed that the surface area of the leaf infected with powdery mildew and consumed by the insect’s larvae increased with larval development, ranging from 1.37 cm² in the first larval instar to 21.86 cm² in the last larval instar. Females were also observed to be more efficient feeders than males, with an average area consumed of 43.97 and 35.94%, respectively. Females fertility was 29.35 eggs per female on okra leaves, with a hatching rate of 94.56%. Based on these results, it was expected that the P. vigintiduopunctata is a promising predator in controlling powdery mildew on different plants due to its natural spread, and encourages further evaluation of the predator’s efficiency under field conditions.

Keywords:

Fungal diseases, disease survey, biological control, Erysiphales, Syria.