Sharpshooters

Sharpshooters are cousins of cicadas and a type of leafhopper (Cicadellidae). And they can bring several diseases to your garden plants.

Blue-green sharpshooter (Katja Schulz) CC BY 2.0

Almonds, blackberries, citrus, cowpeas, elderberries, grapes, and stone fruits are are just a few plants vulnerable to sharpshooter feeding. And their tastes appear to be expanding to include other crops.

Diseases spread by sharpshooters

Once an adult sharpshooter becomes infected with a disease, it will act as a vector for that disease for the rest of its life. Those diseases include the following:

• Alfalfa dwarf--alfalfa
• Almond leaf scorch—almonds
• Citrus variegated chlorosis—citrus
• Olive quick decline syndrome--olive
• Pierce’s disease—elderberries, grapes, and citrus
• Phony peach disease--peaches
• Plum leaf scald--plums

Scientists are still learning about sharpshooters. They believe further research will demonstrate that even more diseases will be associated with sharpshooter feeding. So how do you know if sharpshooters are in your landscape?

​Symptoms of a sharpshooter infestation

Sharpshooters are hard to see. They are very good at hiding. When disturbed, they often leap into the air or shuttle sideways. The first sign of a sharpshooter infestation is leaf stippling. Leaves may also turn brown. New shoots curl and die before they ever get a chance to produce a crop.

These pests feed on the sap found in the xylem. This sap is 95% water, so they must eat a lot to get the nutrients needed. They may be small, but sharpshooters can consume hundreds, or even thousands, of times their body weight in sap in their short lives. [That would be like you or me drinking 400 gallons of water each day!] 

In doing so, they produce large quantities of sticky honeydew. Honeydew is a type of bug poop that contains sugar and ammonia. Honeydew creates the perfect growing medium for sooty mold. You may also see pale exoskeletons scattered about as sharpshooters go through five instars before reaching adulthood.

Sharpshooter nymph on lime stem (Plantlady223) CC BY-SA 4.0

Sharpshooter description

Sharpshooter adults are small, usually one-quarter to one-half an inch long, wedge-shaped, and slender. Depending on the variety, they are brightly colored or may blend with their favorite food plants. Immature sharpshooters are called nymphs. Nymphs look like miniature adults but without wings. They may also be a different color.

​If you look very closely, you will see that the back of their legs are serrated. The most common sharpshooters found in North America include the following:

• Black-winged sharpshooters (Oncometopia nigricans)
• Blue-green sharpshooters (Graphocephala atropunctata)
• Broad-headed sharpshooters (Oncometopia orbona)
• Glassy-winged sharpshooters (Homalodisca vitripennis)

Sharpshooter lifecycle

Sharpshooters overwinter as adults. In late winter, females begin inserting egg masses into the epidermal layer of leaves. She covers these egg masses with a chalky white coating called a brochosome. She carries her brochosomes around on the exterior of her body. Scientists believe that brochosomes keep the eggs moist. Eggs begin hatching in late spring and early summer. There are commonly two generations each year.

Brochosomes (Roman Rakitov) Public Domain

A female glassy-winged sharpshooter carries on her wings masses of specialized brochosomes (the white spot) to be used during egg-laying. (Alex Wild) CC BY 2.0

Sharpshooter management

There are some nasty chemical pesticides used against sharpshooters in commercial environments. You can control them with ultra-light horticultural or neem oils. You can also protect your plants with reflective mulches, row covers, and yellow sticky sheets. And always quarantine new plants. You never know what's lurking.

The easiest way to protect your crops against sharpshooter damage and the diseases they carry is to encourage their natural enemies. These include green anoles, dragonflies, fairyflies, praying mantises, snare-building spiders, and twisted-wing parasites. There are even a couple of fungi known to attack and mummify sharpshooters — but I can’t imagine how you might organize that attack!

You can attract and protect beneficial insects by not using broad-spectrum insecticides, installing insectary plants, and providing a variety of flower shapes, sizes, and colors. Those flowers provide the nectar and pollen that attract and feed your garden helpers.