Mode of Action of Bti and B. sphaericus
Both Bti and B. sphaericus are naturally occurring soil bacteria, with
specific activity against a narrow range of fly pests. These two active
ingredients allow for the effective control of many of the world's vector and
VectoBac's 5 proteins work once they are ingested by the target pest.
The proteins are activated by enzymes and the alkaline pH in the larval
midgut and begin to enlarge the pores thus destroying the cells and opening the
Once the gut wall is destroyed the larvae can no longer eat and die within 24
to 48 hours.
This bacteria is not active in the "acidic guts" of humans and
B. sphaericus (VectoLex®)
VectoLex contains toxic protein crystals and living spores. Larvae eat
VectoLex as they feed.
In the larvae's gut, enzymes cause the proteins to dissolve into smaller
crystals called protoxins.
The protoxins fit themselves to receptors in the gut wall each like a key
fitting a lock. Almost immediately, the protoxins begin to paralyze the
Within a few hours the protoxins begin to "unlock" pores in the gut
wall. The spores begin to invade the body cavity through the pores where they
multiply at an explosive rate The larvae usually dies within two days.