The Investigation of the Biological Control of Icerya purchasi Maskell, 1878 (Hemiptera: Margarodidae) with Entomopathogenic Fungi and Bacteria

Abstract

Cottony cushion scale Icerya purchasi Maskell, 1878 (Hemiptera: Margarodidae) is an important pest that inhibits the plant growth and development by sap sucking of the plants, and causes sooty mold in more than 200 plant species, especially in citrus plantation. The present study investigated the biological control of the nymphs and adult I. purchasi, which densely populates the mimosa plants (Acacia dealbata) in Artvin, Turkey. For this purpose, one fungal isolate [Beauveria bassiana (ET 10)] and eight bacterial strains [Brevibacillus brevis (CP-1), Bacillus thuringiensis subsp. kenyae (FDP-8, FDP-42), B. thuringiensis (FDP-1), B. sphaericus (FD-49), B. pumilus (TV-67C), Pseudomonas fluorescens (RK-1773) and B. atrophaeus (RK-1774)] were assessed against the nymphs and adult of I. purchasi under controlled conditions. Fungal and bacterial suspensions were sprayed onto 20 nymphs and 20 adults of I. purchasi in plastic boxes. The death rates of the nymphs and adults were recorded. The B. bassiana (ET 10) caused a death up to 100% and 80% in nymphs and adults, respectively. Moreover, P. flourescens (RK 1773) caused 90.5% death of nymphs and B. thuringiensis subsp. kenyae (FDP-42) presented 88.5% death to the nymphs of I. purchase. However, the use of the bacterial strains was not much successful against the adults, as compared to the nymphs.