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Leafhoppers

Also known as Cicadellidae, Potato leafhopper, Aster leafhopper, Glasshouse leafhopper

PestHarmful
Empoasca leafhopper, about 3.7 mm long Photo: xpda · CC BY-SA 4.0

In short

Leafhoppers are slender, wedge-shaped insects that jump or fly off when disturbed, while their nymphs scuttle sideways. Their feeding speckles leaves white; some species inject a toxin that scorches leaf edges (hopperburn), and others spread plant diseases such as aster yellows.

How it looks

Adults are about 3–6 mm (1/8–1/4 in) long, slender and wedge-shaped, with wings held roof-like over the body. Most pest species are green, often with bands or spots: the potato leafhopper is light green with white spots behind the head, the aster leafhopper yellow-green with black spots. Hind legs are built for jumping. Nymphs are smaller, with undeveloped wings, and walk sideways like crabs.

Signs

Tiny white or pale spots (stippling) on leaves, similar to spider mite damage; curling, yellowing and stunting. Hopperburn shows as V-shaped yellow to brown, brittle burn at leaf tips and margins that look singed, and is often mistaken for fertiliser or salt injury, drought or herbicide damage. Aster yellows, spread by the aster leafhopper, causes stunting, deformed flowers and witches' brooms; some species also spread bacterial leaf scorch.

What favours it

Mainly a pest outdoors and in greenhouses; the RHS notes the glasshouse leafhopper is found more often in glasshouses than on indoor plants. Weeds provide overwintering sites.

Prevention

  • Cover susceptible crops with row covers or fine insect netting straight after planting.
  • Control weeds that harbour leafhoppers.
  • Monitor with yellow sticky cards and check leaf undersides for nymphs.

Treatment

Start with the first step and move down only if the problem persists.

  1. Encourage natural enemies such as parasitoid wasps, spiders, ladybirds and lacewings.
  2. Vacuuming has been used to remove leafhoppers from herbs.
  3. Insecticidal soap, horticultural oil, neem or pyrethrum sprays reach nymphs best, since adults fly off; follow the product label.
  4. Systemic insecticides are the last resort; follow the product label.

Pros and cons

Cons

  • Hopperburn can stunt plants.
  • Some species spread aster yellows and bacterial leaf scorch.

Look-alikes

Spider mite damage
Similar stippling but with fine webbing and specks rather than jumping insects.
Fertiliser or salt burn
Scorched leaf margins with no insects, cast skins or stippling.
Psyllids
Smaller; nymphs are flat and scale-like rather than active sideways-walkers.

Affected plants

The potato leafhopper alone feeds on over 200 plants, including potato, bean, eggplant, cucumber, pumpkin, rhubarb, squash and sweet potato. Other species attack perennials such as hollyhock, astilbe, Baptisia, dahlia, gaura, hibiscus, lupin and catmint, members of the aster family, and herbs such as rosemary, sage, basil, oregano and thyme.

Sources

  1. Leafhoppers in Home Gardens — University of Maryland Extension
  2. Leafhoppers — UConn IPM
  3. Indoor plants: sap-feeding insects — RHS

Written in our own words from these sources. Check a product label before using any treatment.