Biological Control of Diamondback Moth-Increased Efficacy with Mixtures of Fungi.

Diamondback moth (DBM) is an important horticultural pest worldwide as the larvae of these moths feed on the leaves of cruciferous vegetables. As DBM has developed resistance to more than 100 classes of synthetic insecticides, new biological control options are urgently required. species are entomopathogenic fungi recognized as the most important fungal genus for controlling a wide range of agricultural, forestry, and veterinary arthropod pests. Previous research, aimed at developing new -based biopesticides for DBM, has focused on screening single isolates of . However, these fungal isolates have individual requirements, which may limit their effectiveness in some environments. This current study separately assessed 14 isolates, from a range of habitats and aligned to four different species ( and ), to determine the most effective isolate for the control of DBM. Further assays then assessed whether selected combinations of these fungal isolates could increase the overall efficacy against DBM. Six isolates (three and three ) achieved high DBM mortality at a low application rate with the first documented report of able to kill 100% of DBM larvae. Further research determined that applications of low-virulent isolates improved the control of DBM compared to mixtures containing high-virulent isolates. This novel approach increased the DBM pest mortality and shortened the time to kill.