Tactics of applying entomopathogenic fungi in the control of Plutella xylostella and Brevicoryne brassicae

Abstract

Plutella xylostella L., 1758 (Lepidoptera: Plutellidae) and Brevicoryne brassicae L., 1758 (Hemiptera: Aphididae) are important pests of Brassicaceae, causing significant damage that makes human consumption of these vegetables impossible. As an alternative to the use of chemical insecticides, this study aimed to (i) evaluate the endophytic capacity of the native fungi Fusarium multiceps (Hypocreales: Nectriaceae) and Metarhizium anisopliae (Metschn.) Sorokīn (Hypocreales: Clavicipitaceae) and a commercial strain of M. anisopliae on cabbage plants (Brassica oleracea L. var. acephala) through inoculations via seed treatments, foliar spraying or root applications and (ii) evaluate the mortalities of P. xylostella and B. brassicae fed on plants treated with these fungi. Ten P. xylostella caterpillars or ten B. brassicae nymphs were used per repetition, and the infestations were quantified daily (for P. xylostella) or after 15 days (for B. brassicae). The control treatment consisted of water. The fungi M. anisopliae and F. multiceps demonstrated endophytic colonization capacities in B. oleracea through different inoculation techniques, including application via seeds, leaves and roots. This colonization resulted in the infection and consequent significant mortality of P. xylostella and B. brassicae, reinforcing the potential of these microorganisms as promising agents for biological control.