Leafhopper egg parasitoids (fairyflies)
Anagrus are fairyflies, among the smallest insects you will ever see: about 1/50 in (0.5 mm) long, with fringed wings that let them drift on the wind. A female lays her eggs inside leafhopper eggs, which are embedded in the leaf. The pale egg turns red as the wasp grows inside. Along with spiders, they are the most important natural enemies of grape leafhoppers in California, and a related species is the main enemy of potato leafhopper eggs in alfalfa. No supplier of them was found. They overwinter in other leafhoppers' eggs off the crop, on prune trees for example, and turn up consistently in blackberry and wild rose patches, so habitat near the crop matters most.
At a glance
- Kind
- Wild — no supplier found
- Adult
- About 1/50 in (0.5 mm); fringed wings
- Sign
- Leafhopper eggs in the leaf turn red
- Attacks
- Leafhopper eggs
- Output
- 20–40 eggs per female, ~1-week life
- Overwinters
- In other leafhoppers' eggs, off the crop
How it works
The female searches leaves for leafhopper eggs, which sit hidden under the leaf surface, and lays inside them. If two eggs go into one host, the larvae fight and one survives. The larva grows through about three instars and turns the normally pale egg red. The adult chews a round hole out through the egg and the leaf, leaving dark specks inside. A hatched leafhopper leaves a ragged hole in an empty shell instead. Each female parasitises about 20–40 eggs in a life of about a week, and there are several generations a year. Some species are all female.
There are many species: at least 14 in California, and A. epos alone attacks at least 21 kinds of leafhopper. In California vineyards the most common are A. erythroneurae and A. daanei; in Washington, A. tretiakovae led. In alfalfa, A. nigriventris is the main natural enemy of potato leafhopper. On grapes the wasp cannot spend the winter in the vineyard, so it uses other leafhoppers that overwinter as eggs, on prune, plum, almond and streamside plants. Vineyards next to that habitat can have more Anagrus, and Washington researchers found grape Anagrus species consistently in blackberry and wild rose patches.
What it is confused with
You will rarely see the adult. Read the eggs instead, with a hand lens on an infested leaf.
- PestHealthy leafhopper egg — Translucent white and embedded in the leaf. A parasitised egg turns red or reddish brown.
- PestHatched leafhopper egg — An empty shell with a ragged slit. Anagrus leaves a neat round hole and dark specks inside.
- Also goodAphid parasitoid wasps — Aphid wasps such as Aphidius are up to about 1/8 in (3 mm), several times the size, and leave swollen, tan to golden aphid mummies, not red eggs.
How to keep it around
Anagrus comes on the wind from overwintering sites, so the habitat around the crop decides how early it arrives. In a California study, prune trees next to two vineyards supplied 1 % and 34 % of the first Anagrus to arrive, and marked wasps were caught 100 m (330 ft) away.
- Keep or plant prune, plum or almond near grapes; their leafhoppers overwinter as eggs and carry Anagrus through the winter
- Leave blackberry and wild rose patches; Washington researchers found grape Anagrus species there consistently
- Keep streamside and unmanaged vegetation near the crop where you can
- Grow flowering plants to give the adults nectar
- Delay any leafhopper spray on grapes to the second brood, so the first round of parasitism can work
- Go easy on sulfur, which UC IPM says may be toxic to Anagrus; control ants and keep dust down
Pesticide sensitivity
UC IPM warns that sulfur sprays for mildew may be toxic to Anagrus, and that broad-spectrum, persistent insecticides harm all natural enemies. Alfalfa clones bred with glandular hairs against potato leafhopper also cut the time the wasps spent foraging in lab tests. Open the compatibility matrix →
When to choose something else
Anagrus is strongest on grape leafhopper and weakest where it matters most in vegetable gardens. Look elsewhere when:
- Potato leafhopper is burning potatoes, beans or eggplant. None of the sources read shows a natural enemy stopping hopperburn once migrants arrive; use row cover and a well-timed spray (see leafhoppers)
- The vines carry mostly variegated leafhopper. UC IPM says Anagrus is less effective on it because its eggs sit deeper in the leaf. On Virginia creeper leafhopper, parasitised eggs were scarce in Washington vineyards and UC IPM says its impact in California is still being studied
- You want something to release. No Anagrus product was found; the predators on the leafhopper page are the ones sold
- It is a rose or herb bed with pale speckled leaves. UC IPM says garden leafhoppers generally need no control
Leafhopper egg parasitoids (fairyflies) by target
What it eats and when it turns up differ by pest. Each page below is the picture for one target.