Insecticidal effect of Bacillus pumilusPTB180 and Bacillus subtilisPTB185 used alone and in combination against the foxglove aphid and the melon aphid (Hemiptera: Aphididae)

AbstractThe foxglove aphid, Aulacorthum solani(Kaltenbach) (Hemiptera: Aphididae), and the melon aphid, Aphis gossypiiGlover (Hemiptera: Aphididae), are among the serious insect pests found in greenhouses. The efficacy of microbial control against these insects has been demonstrated and can be enhanced by the combination of different microbial agents. This study evaluated the efficacy of Bacillus pumilusMeyer and Gottheil PTB180 and Bacillus subtilis(Ehrenberg) Cohn PTB185, used alone and together, to control these two aphids both in the laboratory and in greenhouse on tomato, Solanum lycopersicumLinnaeus (Solanaceae), and cucumber, Cucumis sativusLinnaeus (Cucurbitaceae), plants. The results from the laboratory tests showed an increase in mortality induced by all biological treatments. In the greenhouse, all treatments induced mortality rates significantly higher than that of the control for A. solani. Similarly, all treatments performed better than the control against A. gossypii, significantly reducing its reproduction. Furthermore, we found no additive effects when mixing products nor negative interactions affecting survival for the bacteria investigated. These microorganisms therefore have potential for use in biological control.