Agriculture Reference
In-Depth Information
The larva eats the shoot, forming a 1 to 2 in. long gall as it pupates. Canes may break at the
point of the gall. The grape cane girdler is similar.
CONTROL
Prune out visible galls. Clear fallen leaves and debris in late fall.
Grasshoppers
Some species become active in spring, eating young shoots; others are destructive in
late summer when surrounding grasslands have dried up.
CONTROL
Encourage natural predators, including praying mantis and insectivorous birds, although
you may need to net your vines to protect the ripening grapes from the birds later in the
season. Till soil to expose eggs to predators. Plant cover crops. Treat with diatomaceous
earth, neem oil, or pyrethrins.
Japanese Beetles
Familiar to gardeners in eastern North America, Japanese beetles are metallic-looking
green beetles that can swarm over plants in early summer, sometimes decimating foliage.
June beetles are similar, but larger and reddish brown.
CONTROL
Beneficial nematodes may help control larvae and reduce populations.
Bacillus thuringien-
sis
(Bt) and milky spore (
Bacillus popillae
) can treat larvae. Check with your local exten-
sion service for new beneficial insects to control adults. Pheromone traps tend to encourage
more beetles, so position them away from your grapes. Pyrethrins and diatomaceous earth
may help kill adults.
