Tuesday, October 30, 2012

Bt - An Effective, Organic Pesticide

Bt, which is the bacterium, Bacillus thuringiensis (sold as  Dipel, Gnatrol, and Thuricide) is an effective organic pesticide specific to caterpillars, fungus gnat and mosquito larvae.

The problem is that Bt does not kill immediately, and therefore, gardeners may think the product is ineffective. The bacterium produces a toxin that, when ingested, causes gut paralysis and eventual death. The affected caterpillar will stop feeding within hours of ingestion, but it may take a day or two to actually die.

In addition, Bt rapidly degrades in sunlight. For best results, applications should be made in the late afternoon. Most caterpillars feed after dusk anyway.  Bt is especially effective against the green garden looper which commonly attacks many vegetable crops and some ornamental crops, including ti and tropical foliage.