Susceptibility pattern and development of resistance in the diamondback moth, Plutella xylostella L, to Bacillus thuringiensis Berl var kurstaki in India
M. Mohan et Gt. Gujar, Susceptibility pattern and development of resistance in the diamondback moth, Plutella xylostella L, to Bacillus thuringiensis Berl var kurstaki in India, PEST MAN SC, 56(2), 2000, pp. 189-194
Base-Line susceptibility for six-day-old larvae of the diamondback moth, Pl
utella xylostella, against Bacillus thuringiensis var kurstaki (Biobit(R))
was studied by a cabbage leaf disc dip bioassay technique. Diamondback moth
from 13 locations in seven different states spread over a distance of abou
t 3000 km longitudinally was used for these studies. Forty-eight-hour LC50
values varied from 1.0 to 10.97mg Al litre(-1) Further investigations on th
e development of resistance under laboratory conditions showed an increase
in LC50 from 2.76 (for unselected Fl generation) to 5.28mg AI litre(-1) (fo
r selected Fg generation), using a selection concentration of 6.4mg Al litr
e(-1). This suggested a possibility of the development of resistance under
field conditions if there were to be extensive and indiscriminate use of B
thuringiensis. These findings are discussed in relation to integrated pest
management and the mechanisms of resistance in resistance management tactic
s. (C) 2000 Society of Chemical Industry.