If your landscape could talk, like it does in TV commercials, it would tell you that the flowers are thirsty, the shrubs are complaining about the heat, and there are grasshoppers and bagworms eating the garden. But unlike the homeowner in the shoot, instead of running to the phone to call a professional, head to the garden to investigate and begin making plans for controlling these unscrupulous feeders. Here is what you need to know about controlling grasshoppers and bagworms in the landscape.
Grasshoppers overwinter as eggs in small banana-shaped pods deposited underground in the fall. When the temperatures warm in the spring, the eggs hatch, and tiny immature grasshoppers emerge and begin feeding. There is generally only one generation of hoppers per year.
Similarly, the second week of June was about the halfway point of the four- to five-week period of bagworm egg hatch. Bagworms overwinter as eggs left behind in bags of female adults that hung in trees or shrubs all winter long. The earliest bagworms are still small and may go undetected because they are not yet causing major damage.
Most grasshoppers feed on a wide range of plant material. Some feed primarily on different grass species, while others prefer broadleaf plants. Yet others will eat just about anything - including each other. Grasshoppers normally stay in the hatching areas as long as host plants provide an acceptable food source. When the food is all eaten or dries up, adult grasshoppers can set out in search of new food sources. Areas of high moisture are usually attractive to the foraging adults. That is why, in years of drought, hoppers can invade your irrigated flower beds and vegetable gardens seemingly overnight.
Bagworms are different in that they are not mobile like hoppers. For the most, bagworm larvae will feed on the plant they were born on all summer long. They are, however, like grasshoppers in that they have a diverse taste for many different plants and can consume large amounts of plant material as they mature.
The secret to minimizing the damage caused by grasshoppers and bagworms is to begin control strategies early in the season. The older they get, the more difficult they are to control and the more damage they cause. For grasshoppers, center your efforts on their breeding grounds. These are usually dry, undisturbed areas of the garden or flower bed. Products such as Sevin, esfenvalerate, malathion, acephate (Orthene), and permethrin are all labeled for grasshopper control. Use Sevin and permethrin in vegetable gardens. There are 337 insecticidal products registered for use against bagworms in Kansas. They all will work, but none of them will perform magic. When and how you use each product is more important than which one you choose to use. When considering a single spray treatment, the last week of June or the first week of July is the best time to treat for current-season bagworms. At that time, all eggs will have hatched and feeding worms can be controlled easily. But remember, these chemicals can and will kill off target insects as well. So be careful when spraying the butterfly garden and other gardens with desired insect species. As always, read and follow all label directions.