Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2009
Publication Date: 6/12/2009
Citation: Martin, P.A., Farrar, R.R., Blackburn, M.B. 2009. Survival of diverse bacillus thuringiensis strains in gypsy moth (Lepidotera: Lymantriidae) is correlated with urease production. Biological Control. 51:147-151.
Interpretive Summary: Using bacteria that cause disease in pest insects is a good alternative to chemical control. Bacteria such as Bacillus thuringiensis (Bt) are successful because they can be applied like chemical insecticides. We wanted to find ways to improve the chances of Bt being transmitted from infected insects to healthy ones. Using a gypsy moth system, we determined that for Bt to multiply and complete its life-cycle in an insect, the bacteria needed to produce a particular protein to help it digest the insect. Scientists searching for better strains of Bt can use this information to select bacteria that can multiply, survive, and be passed on to other insects for sustainable insect control.
Technical Abstract: Bacillus thuringiensis is an entomopathogenic bacterium that can kill a variety of pest insects, but seldom causes epizootics because it replicates poorly in insects. By attempting to repeatedly pass lepidopteran-active B. thuringiensis strains through gypsy moth larvae, we found that only those strains producing urease were capable of surviving repeated passage. Lecithinase production and the inability to produce acid from sucrose appeared to be correlated with surviving strains, but not when the urease effect was taken into account. Urease activity can serve as a useful screen for selecting B. thuringiensis strains with a greater capacity for insect to insect transmission.