Leaf Hoppers

Leaf hoppers are tiny insects measuring about 6mm. There are many different kinds but the ones that give us the most grief are potato leaf hoppers. 

Leafhopper (left)-University of Kentucky, R. Bessin, Leafhopper (right)-University of California, L. Dunning

Description 
These guys are greenish in colour (can be other colours sometimes striped) and they hop all over the place if they are disturbed. Immature guys can’t fly but the mature ones have wings. (I don’t like these guys!)

Nymph-L. Townsend

Habitat & Lifecycle
They appear in large numbers on bean, beets, potatoes and many fruit trees and also grapes. I’ve even had them on my radishes and they are quite a nuisance en masse. They love full sun so I would try to plant my vulnerables in a place with shade most of the day in the summer. In some climates they can reappear in July and August.

Damage on potatoes (left)-University of California, D.H. Hall, Damage (right)-University of California, Jack Kelly Clark

Damage
Growth of plants is stunted. These guys are sap sucking insects feeding on the underside of leaves. The leaves turn yellow and curl under where these guys hide. They can spread a disease called ‘curly top virus’. The potato guys spread disease called ‘hopperburn’ . Both of these diseases will kill your plants very quickly.

Curly Top Virus-Colorado State University

Control
1) Sticky Traps
I put honey, molasses or another sticky substance like tanglefoot on a piece of stiff cardboard and wave it over the plants and they will stick to the boards after which you can destroy. Remove any affected plants and destroy them. Don’t put them in your compost.
2) Predators
Lacewings, praying mantids, lady bugs, pirate bugs, spiders and birds like gnatcatchers and warblers.
3) Use a Soap and Garlic Spray
Garlic/Pepper Tea
Liquefy 3 bulbs of garlic and 5 cayenne peppers in a blender with two cups of water. Strain off all the solids and add enough water to make a gallon of liquid – This is your concentrate. Use only 1/4 cup of concentrate to a make gallon of solution. For an additional punch, add a tablespoon of vegetable oil or horticultural oil to each gallon of water in your sprayer. Be sure and wear gloves when working with peppers.
4) Row Covers
There are row covers you can purchase from your local nursery