ARS | Publication request: New records of entomopathogenic fungi infecting Bemisia tabaci and Trialeurodes vaporariorum, pests of horticultural crops, in Argentina

Submitted to: Biocontrol
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 28, 2007
Publication Date: N/A

Interpretive Summary: This paper reports the results of three years of surveys for entomophthoralean fungal pathogens affecting the two most important species of whitefly pests in organic and conventional crops in Argentina. These studies found diseases caused by five different species of conidial fungi that are globally distributed and may be expected to be among effective pathogens on a wide range of insect pests affecting a similarly wide range of different crop plants. These fungi, all of which were isolated in pure cultures represent the first published records of their presence in the southern regions of South America. Preliminary data on these fungi - Lecanicillium lecanii, Lecanicillium muscarium, Lecanicillium longisporum, Isaria fumosorosea, and Isaria javanica - indicate that they may be worthy of further consideration for development as biocontrol agents against these whitefly hosts.

Technical Abstract: The whiteflies (Hemiptera: Aleyrodidae) Bemisia tabaci (Gennadius), and Trialeurodes vaporariorum (Westwood) are major crop pests throughout the world. Although extensive research about biological control of whitefly has been conducted towards these insect's parasitoids and predators, several entomopathogenic fungi are recognized as important biological control agents. Surveys were carried out in organic and conventional horticultural crops in greenhouses and open fields in Buenos Aires and Corrientes provinces, Argentina, and resulted in the recovery and isolation from whiteflies of Lecanicillium lecanii (Zimmerm.) Zare & W. Gams, L. muscarium (Petch) Zare & W. Gams, L. longisporum (Petch) Zare & W. Gams, Isaria fumosorosea Wize and I. javanica (Frieder. & Bally) Samson & Hywel-Jones. Pathogenicity tests were conducted against T. vaporariorum nymphs using a conidial suspension (1 x 107 conidia/ml) of the fungal isolates selected. A mortality rate between 26.6% and 76.6% was obtained at 7 days post-infection. These are the first records of natural infections in the southernmost region of the neotropic of L. lecanii, L. muscarium, L. longisporum and Isaria javanica, (Ascomycota: Hypocreales) on T. vaporariorum and also the first report of I. fumosorosea on B. tabaci, the most important pest of horticultural crops in Argentina.