What is the green worm that eats my roses and columbine every year?
It is hard to diagnose your problem without seeing the caterpillar. There are several green worms that bother roses, and one can be controlled with Bt (Bacillus thuringiensis) but rose slug, for example, cannot. Proper identification is necessary before applying any control method. Do not use an insecticide for anything that"s not on on the product label. Do not use any insecticide as a preventive measure. It doesn"t work and ends up being harmful to the environment and a waste of your money.
Green worm on your columbine could be an inch worm or canker worm. If the caterpillar loops up in the center or arches as it moves along, it could be a looper or cabbage worm. Leaf miners, which are usually white or pink, tunnel in the leaves. “To eliminate insects, use insecticidal soap,” said Nancy Clifton, Chicago Botanic Garden Plant Information Specialist.
For an exact diagnosis, consult your local University of Illinois Extension service or collect a specimen and bring it to the Plant Information Service at the Chicago Botanic Garden or the Morton Arboretum.
I plan on saving my amaryllis bulbs that I kept outside over summer, but I noticed red streaks on the inner side of the leaves. What caused that? Will I be able to save my bulbs?
I keep seeing photos of interesting plants I’d like to grow, but they’re labeled zone 6 and I’m in zone 5. What can I do to successfully overwinter these marginal plants? I’d like to try them, but I don’t want to waste my money.
My lilac had a grayish blight on the leaves this summer. What caused this and how can I prevent it?