Worms In My Sweet Broom - Knowledgebase Question

North Hills, CA
Question by lgerns
October 3, 2001
I planted a lovely yellow sweet broom plant in the middle of my flower bed and it has developed an ugly worm infestation.
They appear to be yellow and black and seem to spin a web of some kind. I've tried picking them off, but they seem to come back. The worms have only attacked that one plant.


Image
Answer from NGA
October 3, 2001

0

laid on the undersides of leaves and are protected by a woolly or scaly covering. Eggs are deposited from late spring through fall. Remove any affected leaves and destroy them. This strategy requires time and sharp eyes and is obviously impractical for tall trees.

When you see webs, clip the infested branches and burn them, or drown the larvae in a bucket of soapy water.

As a last resort, Bacillus thuringiensis (Bt) is a microbial pesticide that can be applied as a dust or spray. It kills many types of caterpillars but has no effect on warm-blooded animals or bees.

With fall webworms, Bt is effective only if its application is properly timed. Once the caterpillars have enshrouded themselves in webs, they are more difficult to kill. Check on susceptible plants frequently, beginning in late spring, and apply Bt at the first sign of hatching webworms. Bt loses effectiveness after about two days, so it must be reapplied as long as more larvae are hatching.

Always use Bt with care, because it also can kill the larvae of non-pest moths and butterflies.


laid on the undersides of leaves and are protected by a woolly or scaly covering. Eggs are deposited from late spring through fall. Remove any affected leaves and destroy them. This strategy requires time and sharp eyes and is obviously impractical for tall trees.

When you see webs, clip the infested branches and burn them, or drown the larvae in a bucket of soapy water.

As a last resort, Bacillus thuringiensis (Bt) is a microbial pesticide that can be applied as a dust or spray. It kills many types of caterpillars but has no effect on warm-blooded animals or bees.

With fall webworms, Bt is effective only if its application is properly timed. Once the caterpillars have enshrouded themselves in webs, they are more difficult to kill. Check on susceptible plants frequently, beginning in late spring, and apply Bt at the first sign of hatching webworms. Bt loses effectiveness after about two days, so it must be reapplied as long as more larvae are hatching.

Always use Bt with care, because it also can kill the larvae of non-pest moths and butterflies.


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