Types

• The black vine weevil was first found in the United States in 1910 in the state of Connecticut. Adult black vine weevils have a wide host range, feeding on more than 100 different species of plants, including hostas. Trees, shrubs, flowers and vines are all in the diet of the black vine weevil. Grasshoppers are another common hosta pest. These bugs feed on a variety of shrubs, trees and plants, often eating their own body weight in green food. Foliar nematodes often infest hosta leaves and are microscopic worms that overwinter in the soil. These pests move to hosta leaves for feeding. Foliar nematodes are typically difficult to control on hostas.
  
  

Effects

• Serious injury to infested plants is possible with large populations of black vine weevils, which feed on hosta leaves in their larval stage. Notches and holes in hosta leaves is a sign of heavy infestation of black vine weevils. A single grasshopper can consume large portions of hosta leaves, and large populations can consume entire plants. This pest multiplies rapidly, with one female laying more than 400 eggs in one season. Foliar nematode feeding causes a brown streak to develop on host plants. This discoloration appears on hosta leaves between the leaf veins during July or August.
  
  

Nonchemical Control

• Placing plants in your garden that are resistant to the black vine weevil is one way to prevent infestations. Hostas are favored hosts to this insect, as well as rhododendron and euonymus. Handpicking the black vine weevil from your hostas is one way to control light infestations. If large numbers of weevils are present, chemical control methods are recommended. Grasshoppers are often controlled by natural predators such as birds and spiders. Heavy infestations of grasshoppers require chemical control methods to prevent severe damage to your hostas. There are currently no control methods proven to eliminate or control foliar nematode infestations on hostas.
  
  

Chemical Control

• Black vine weevils are best controlled with insecticidal sprays when they first emerge. Apply insecticides to hosta leaves, as well as the soil where beetles hide during the daytime hours. Control of the black vine weevil larvae is best accomplished with soil drenches available at your local garden center. Grasshoppers are controlled with insecticides in a granular form or spray. There are several products that can be placed near hostas that serve as grasshopper bait. Once grasshoppers consume the bait, they die quickly. It is often necessary to repeat applications of chemical control products to prevent reinfestations in your yard or garden.