ARS | Publication request: Beauveria bassiana Infection of Eggs of Stored-Product Beetles

Submitted to: Entomological Research (Korea)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 2, 2008
Publication Date: March 1, 2009
Repository URL: http://doi:10.1111/j.1748-5967.2009.00208.x
Citation: Lord, J.C. 2009. Beauveria bassiana Infection of Eggs of Stored-Product Beetles. Entomological Research 39: 155-157.

Interpretive Summary: Insect pathogenic fungi have been shown to attack the larvae and adults of many pests of stored products, but whether they can infect the eggs of those insects is unknown. Beauveria bassiana, a fungus that is registered for insect control, was tested under maximum challenge conditions for its infectivity for four of the major beetle pests of stored grain and grain products. When ambient humidity was set at 92%, exposure to the fungus caused reduced hatch of lesser grain borers and red flour beetles, but there was no effect at lower humidities. Fungus treatment of rusty grain beetle and sawtoothed grain beetle eggs had no effect. This information helps target the appropriate vulnerable insect stages when using fungal insecticides.

Technical Abstract: Beauveria bassiana (Balsamo) Vuillemin was tested under maximum challenge conditions with a dose of estimated dose of 1.1x105 conidia/mm2 for its effects on eggs of four of the major beetle pests of stored grain and grain products. When ambient relative humidity (RH) was 92%, hatch of fungus-treated Rhyzopertha dominica (Fabricius) eggs was 13% vs. 58% for control eggs, and hatch of treated Tribolium castaneum (Herbst), was 17% vs, 51% for controls. There was no fungus effect at RHs of 48 and 73%. Fungus treatment of Cryptolestes ferrugineus (Stephens) and Oryzaephilus surinamensis (Linnaeus) eggs had no effect. Sectioned R. dominica eggs demonstrated that the fungus penetrates and infects them.