BeneficialCutworms
Bt (kurstaki) for cutworms
Bacillus thuringiensis kurstaki · microbial insecticide
Against cutworms
Bt is a weak tool against cutworms. UF/IFAS says it is not usually recommended, and UC IPM says it is less effective against cutworms and armyworms than against sod webworms and should only be used on young larvae. Older cutworms feed at the soil line, where a spray on the leaves never reaches them. Collars and night picking work better in a garden.
RateLabel rate — DiPel DF lists cutworm (Agrotis ipsilon) and variegated cutworm, 0.5–2 lb per acre; on berry crops the label says to use the higher rate for cutworm
TimingFirst and second instars only, while they still feed on foliage
Before you order
A bacterium sprayed on leaves. Caterpillars that eat it stop feeding and die within a few days. It works only on the larvae of moths and butterflies, and has little or no effect on bees, lady beetles, lacewings or parasitic wasps. How it works, how to tell it has established and the supplier list are on the full Bacillus thuringiensis kurstaki profile.
Other controls for cutworms
- Steinernema carpocapsaeNematode · 25 million per 1,000 ft² (about 270,000 /m²) in turf (UC IPM); about 1 billion per acre (PNW544)
- Ground beetlesWild predator · Nothing to release — give them cover
- Braconid waspsWild parasitoid · wild, attract it