ANAGRUS WASPS
Scientific name
Anagrus spp.
Identification
Larvae:
- Initially opaque, white oval shape inside the translucent egg of the leafhopper
- Becomes light tan and appears segmented
- Eventually it fills the entire egg chamber
- As hatch nears, legs, abdominal segmentation and red eyes can be distinctly seen
- Medium to dark brown, 0.4 mm long
- Completely fills the egg chamber
- Dark pigmentation in the parasitized egg
Adult:
- Tiny, delicate dark brown wasp about 0.5 mm long
- Fringe of hairs bordering both pairs of wings
- No wing veins
- Small and very narrow hind wings
- Long and thread-like antennae
Interaction With Host
Anagrus survives the winter as a partially grown larva
inside the egg chamber of its host. This species must overwinter in a
host that overwinters in the egg phase. Since members of the leafhopper
complex overwinter as adults, the wasp requires other leafhoppers and
their hosts in which to overwinter. Alternate insect hosts of Anagrus
spp. occur on several non-crop perennial plants adjacent to vineyards.
Such plant hosts include black willow, black locust, prickly ash, wild
rose, dogwood, black walnut, northern red oak, hawthorn, wild black cherry,
white ash, wild blackberry and French prune.
Following emergence from their overwintering hosts, Anagrus adults tend to gather in the edges of the vineyard early in the growing season (May and June). They slowly move into the vineyard and by August they can be found in grape leafhopper eggs throughout in the vineyard.
Period of Activity
Vineyard borders late May through June; throughout the vineyard in mid-summer through harvest.
Insects Attacked
Leafhopper species.
Monitoring and Management
From early spring through the time the adult parasites emerge, either
the larva, pre-pupa or
pupa can be distinguished
from a normal leafhopper embryo. The round exit hole left by the adult
parasite (and at one end of the egg chamber) can be seen with a hand lens.
Adults can be monitored with yellow sticky traps used for leafhopper adults.
Anagrus are sensitive to broad spectrum insecticides and some fungicides. For more information on the toxicity of pesticides to beneficial insects see the Impact of Pesticides on Beneficials.
