Wednesday, September 10, 2008

Budworms ate my blossoms

Penn State Master Gardeners have established several fantastic demonstration gardens at Neshaminy Manor Center, where our Extension office is located. We recently received the Pennsylvania Horticulture Society “Community Greening Award”.

But there is trouble in paradise. The tobacco budworm has eaten virtually every blossom and flower bud from our petunias! Purple ones, white ones, pink ones. We knew what was up because this is a recurring problem. Initially, we thought that the petunias simply stopped blooming but on closer inspection it was easy to see the chewing damage. Once we caught one of the caterpillars it was easy to solve the mystery.

Several weeks ago we applied Bt, (Bacillus thuringiensis) a biological insecticide, and that did the job. We must be into the next generation of budworms now because the color is again gone from our petunia beds. The Bt treatment only lasts a short time.
So, if your petunias (or geraniums or tobacco)seem to have mysteriously stopped blooming, check the flower buds for ragged, chewing feeding symptoms. The insects themselves are elusive, feeding at night and hiding during the day. A shot of Bt did the trick for us. Other insecticides will work but Bt is quite selective for caterpillars and so that is a good choice.

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