The budworm (a type of caterpillar/moth) is commonly found in geraniums, petunias, snapdragons, and other flowering plants, as well as trees. They are very small and they tend to take on the color of the bloom or foliage they are infesting. The numerous black droppings they leave behind are one of the telltale signs.
Many gardeners may not know they have a problem until the damage becomes severe. New foliage of the host is preferred. In the spring, in trees, small larvae mine in needles and later enter the swelling buds. Effects can be devastating to any tree or ornamental.
Controlling the budworm is simple. You can control the budworm by a bi-weekly spraying of the unopened geranium buds, nearby stems and leaves with Orthenex, a systemic insecticide. When spraying petunias cover the entire plant. The spray will protect a plant for about two weeks. If you prefer a natural method, spray the geraniums or petunias thoroughly with Bt,(Bacillus thuringiensis), a bacteria that attacks the worm. As soon as the worm eats the flower, leaf or bud sprayed with Bt it stops eating, but it takes a few days for it to die. Be aware that Bt has little residual effect and must be used frequently and regularly to control the worms. You have to keep a sharp eye for the young worms and spray the plant immediately.