PJB-2022-136
FUNGAL DIVERSITY ASSOCIATED WITH BEMISIA TABACI GENNADIUS (HEMIPTERA: ALEYRODIDAE) ON CUCUMBER AND COMPARATIVE EFFECTIVENESS OF BIOASSAY METHODS IN IDENTIFYING THE MOST VIRULENT ENTOMOPATHOGENIC FUNGI
ABDULNABI ABBDUL AMEER MATROOD
Abstract
Bemisia tabaci (Gennadius) is a serious pest of cucumber, in Iraq that reduces the income of farmers by high losses in yield. This study aimed to identify entomopathogenic fungi from whitefly cadavers and to evaluate their relative frequency and various structural attributes. Thereby, the suitably of two bioassay methods and the virulence of two entomopathogenic fungal species were evaluated for management of B. tabaci under greenhouse condition. Of the 16 fungal species isolated from the whitefly cadavers, only 2 species were confirmed microscopically as known entomopathogenic species: Mucor sp. (Fresenius) and Paecilomyces lilacinus (Thom) with a relative frequency of 8.65 and 5.82%, respectively. Results of the principle component analysis indicated that the first two PCs explained 99.30%. Three factors had a significant positive correlation with relative frequency of the fungal species which are species diversity (r= 0.983), Simpson’s concentration of dominance (r= 0.951) and equitability of evenness (r= 0.996). The mortality greatest effect of B. tabaci nymphs and adults due to P. lilacinus and Mucor sp. was registered on 7 days after inoculation with an average mortality more than 60% (for 100% of conidia filtrate and for 106 conidia/ml). P. lilacinus and Mucor sp. were significantly more virulent to nymphs than adults (the adults mortality is approximately half of the nymphal mortality). However, no significant differences were observed between mortality rates of the two methods. To control B. tabaci nymphs and adults in field within IPM strategies, we suggest future trials are required in order to analyze the real efficacy of P. lilacinus and Mucor sp. under field conditions.
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