The female flies from plant to plant laying eggs on the leaves. The eggs hatch in three to five days and the young worms begin feeding. During this stage caterpillars are easiest to control. Make insecticide applications immediately upon finding young worms on the broccoli. Once the worms reach inch in length, they are more difficult to control with an insecticide.
Most caterpillars have a similar life cycle and cause similar damage.
Several species of general feeders, including cutworms, corn earworm, fall armyworm and garden webworm can cause damage to broccoli. Diseases Diseases must be controlled in order to produce quality broccoli. Diseases often reduce yields and in some cases may eliminate an entire stand. Most serious broccoli diseases can be introduced to a clean field on diseased transplants. Growers can avoid two of the most serious diseases, black rot and black leg by purchasing certified transplants or direct seeding only seed certified free of black rot and black leg.