Virulence of Verticillium lecanii (Z.) against cereal aphids; does timing of infection affect the performance of parasitoids and predators?
Article first published online: 4 SEP 2012
© 2012 Society of Chemical Industry
Pest Management Science
Volume 69, Issue 4, pages 493–498, April 2013
How to Cite
Aqueel, M. A. and Leather, S. R. (2013), Virulence of Verticillium lecanii (Z.) against cereal aphids; does timing of infection affect the performance of parasitoids and predators?. Pest. Manag. Sci., 69: 493–498. doi: 10.1002/ps.3398
- Issue published online: 20 MAR 2013
- Article first published online: 4 SEP 2012
- Accepted manuscript online: 3 AUG 2012 12:00AM EST
- Manuscript Accepted: 3 AUG 2012
- Manuscript Revised: 9 JUL 2012
- Manuscript Received: 29 NOV 2011
- tritrophic interactions;
- cereal aphids;
- Verticillium lecanii (Z.)
BACKGROUND: Entomopathogenic fungi such as Verticillium lecanii (Z.) (Mycotal®) are used for pest control as an alternative to chemical control. In this study, the effect of V. lecanii on cereal aphids is assessed. In addition, an investigation is carried out to determine whether the use of V. lecanii affects the performance of two natural enemies of aphids, the predator Harmonia axyridis (P.) and the parasitoid Aphidius colemani (V.), in no-choice experiments under laboratory conditions.
RESULTS: The number of Rhopalosiphum padi (L.) and Sitobion avenae (F.) killed was increased by increasing the concentration of V. lecanii. The timing of application of fungus to aphids affected the efficacy of other biocontrol agents, a parasitoid and a predator. Parasitation by A. colemani (V.) in both cereal aphids (S. avenae and R. padi) was not affected by V. lecanii when aphids were first treated with V. lecanii and then exposed to A. colemani. The emergence of adults from parasitised mummies was, however, lower in infected aphids than in uninfected aphids when the aphids were first exposed to the parasitoids and then treated with fungus. The female sex ratio in the emerging adults was lower in V. lecanii-treated aphids in both species. When aphids were first treated with V. lecanii, 72 h before predation, fewer aphids of both species were consumed by H. axyridis (P.).
CONCLUSION: Use of entomopathogenic fungus as a biological control agent could be a complementary strategy in an integrated pest management programme against cereal aphids, but it can reduce the efficiency of other biocontrol agents (parasitoids and predators) when applied simultaneously. © 2012 Society of Chemical Industry