Combined use of entomopathogenic fungi and their extracts for the control of Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae)

Publication date: January 2016 Source:Biological Control, Volume 92 Author(s): G. Resquín-Romero, I. Garrido-Jurado, E. Quesada-Moraga Both the virulence and insecticidal activities of the crude extracts of 26 isolates of the entomopathogenic mitosporic ascomycetes Metarhizium sp. and Beauveria sp. (Ascomycota, Hypocreales) were evaluated against the second-instar larvae of Spodoptera littoralis (Boisduval) (Lepidoptera, Noctuidae), a very harmful polyphagous insect pest. Although all isolates caused infection when the second-instar S. littoralis larvae were immersed in the conidial suspensions, only four isolates of Beauveria (EABb 01/33-Su, EABb 01/88-Su, EABb 01/103-Su, and 3155) and one isolate of Metarhizium caused >50% mortality of the larvae, with average survival times (ASTs) of 9.67 and 8.73days for the isolates EABb 01/33-Su and EABb 01/88-Su, which caused the highest mortality rates of 78.33% and 75.00%, respectively. The LC50 and LT50 values were 5.69×106 conidiaml−1 and 6.76days for EABb 01/33-Su and 1.05×107 conidiaml−1 and 7.02days for EABb 01/88-Su. By contrast, the crude extracts obtained from the Metarhizium brunneum EAMb 09/01-Su and EAMa 01/58-Su isolates caused the highest mortality rates of 80.00% and 66.66% and the lowest ASTs of 5.13 and 4.43days, respectively. Topical application of the crude extracts did not cause mortality. Combined treatments with fungal suspensions of the isolates EAMb 09/01-Su and EAMa 01/58-Su and their e...

Source: Biological Control - November 13, 2015 Category: Biology Source Type: research