ABSTRACT
Laboratory studies were performed to explore the effects of host-plant quality on the vulnerability of Plutella xylostella to Bacillus thuringiensis. P. xylostella were kept on different host plants, including Brassica pekinensis (Chinese cabbage) cv. Hero, Brassica oleracea var. botrytis (cauliflower) cv. Royal, and B. oleracea var. capitata (common cabbage) cv. Globe Master (white cabbage) and cv. Red Dynasty (red cabbage) for at least two generations. These host plants are considered as the high (Chinese cabbage), intermediate (cauliflower and white cabbage) and low-quality (red cabbage) hosts for P. xylostella. The vulnerability of the pest larvae was then tested using two formulation of B. thuringiensis var. kurstaki, including Biolarv® and Biolep®. The results demonstrated that the susceptibility of P. xylostella to B. thuringiensis was influenced by host-plant quality. Indeed, B. thuringiensis acted better on the pest fed on the low-quality host plant compared with that on the high-quality host plant. The interaction between the pathogen and plant quality/resistance resulted in more mortality of the pest larvae, implying a synergistic effect. From a pest management viewpoint, these findings may be promising for the integration of the pathogen and the low-quality/partially resistant host plants against P. xylostella in field studies.
Acknowledgements
We thank the late Dr Ali H. Sayyed (Department of Biochemistry, School of Life Sciences, University of Sussex, Brighton, UK) for advising on bioassays.
Disclosure statement
No potential conflict of interest was reported by the authors.
ORCID
Javad Karimzadeh http://orcid.org/0000-0002-4848-9293