Mortality of the Western corn rootworm, Diabrotica virgifera virgifera larvae caused by entomopathogenic fungi

Abstract

Mortality of the Western corn rootworm (WCR) larvae caused by entomopathogenic fungi Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae was investigated in a laboratory. Larvae were treated with a spore suspension (concentration of 2 x 10 7 conidia/ml) by immersion. Only one strain of entomopathogenic fungi, a strain of B. brongniartii, significantly influenced mortality of WCR larvae after 7 days. Average mortality of the larvae was 17.63%. After 14 days, five strains of B. bassiana, two strains of B. brongniartii and one strain of M. anisopliae significantly influenced mortality of WCR larvae, with average mortality ranging from 25.83% to 60.57%. After 21 days from exposure of the larvae to spores, four strains of B. bassiana, two strains of B. brongniartii and one strain of M. anisopliae significantly influenced mortality of the WCR larvae with average mortality ranging from 62.5% to 86.6%. Results confirmed that interaction is possible between fungal strains and insect of a various geographical provenance. More than half of the tested fungal strains significantly influenced the mortality of WCR larvae after 14 and 21 days. It was found that differences between strains were more important than differences between fungal species.

Biology and Management of Pest Diabrotica Species in South America

“…Biological control with pathogens and nematodes offers a different outlook, with several promising laboratory and greenhouse results. Several strains of Beauveria bassiana, B. brongniartii (Hypocreales: Cordycipitaceae), and Metarhizium anisopliae (Hypocreales: Clavicipitaceae) were effective in controlling Diabrotica virgifera virgifera larvae for up to 21 days after application [110]. Similar results have been obtained for South American species.…”

Effect of Beauveria bassiana (strain ATCC 74040) on two leaf beetle pests of maize under laboratory conditions

“…Testing twenty strains of B. bassiana, B. brongniartii (Saccardo) Petch and M. anisopliae at a concentration of 1 × 10 7 conidia/ml against larvae and adults of WCR in the laboratory Pilz et al (2007) reported that isolates of M. anisopliae caused significantly higher mortalities than isolates of B. brongniartii and B. bassiana. Similarly, 21 days after inoculation, a strain of M. anisopliae (MA1) caused higher mortality of the WCR larvae than the strains of B. bassiana and B. brongniartii, all strains were tested at a concentration of 2 × 10 7 conidia/ml (Cagáň et al, 2019).…”