Bacillus thuringiensis (BT) is a naturally occurring bacteria that causes diseases in many different insects. The advantage of this bacteria when used as an insecticide, is that various strains of the bacteria are specific to certain types of insects. For example, when the kurstaki strain of Bt is used to control plant-feeding caterpillars, Ladybird beetles, lace wings and pirate bugs are not affected by the treatment.
- aizawai - Lepidoptera species such as Geranium Budworm, Peach twig borer, European corn borer, armyworm, grapeleaf skeletonizer
- israelensis - fly species such as the fungus gnat, a pest of many house plants
- kurstaki - Lepidoptera species - similar to aizawai
- Serotype H-14 - labeled for for mosquito larva
- tenebrionis - Coleoptera (beetles) such as Colorado potato beetle, elm leaf beetle and cottonwood leaf beetle
Strains of Bt and the insect pests they control *
* Extracted fromVolume 8, 1995 Insect Control Guide, Meister Publishing Company.
As with any insecticide these materials should be applied when the insect is small and newly-hatched. For specifics on the time of application contact the Extension office in your county or your state's Land Grant College.
For further information on Bt refer to the On-line Fact Sheets at Colorado State University. You will need to download the Acrobat Reader in order to view these publications, but a link has been provided on that CSU page to facilitate the downloading of that program. The publication on BT is located under the category of Garden - Insects.
to the Main Page of the Geranium Budworm
WebMaster Dr.
Curtis E. Swift, Area Extension Agent, Horticulture
Colorado State University Extension
2775 US Hwy 50, Grand Junction, CO. 81503
voice: 970-244-1834
fax: 970-244-1700<