Leafhopper

A Leafhopper is a common name applied to any species from the family Cicadellidae. Leafhoppers are widespread, serious pests of many species, whether grown under protection or outdoors. Leafhopper damage currently leads to substantial crop losses.

Symptoms
Leafhopper damage has the appearance of indistinct white or pale yellow spots or flecks on the leaves, which later coalesce to form bleached areas. Small black faecal spots left by the leafhoppers on the leaves are sometimes visible.

Chemical

 * Eradicoat (vegetable oil extracts/glucose polymer), acts by physical means. May currently be used on any crop.
 * Majestik (natural plant extracts), acts by physical means. May currently be used on any crop.
 * Savona (fatty acids), has Specific Off-label Approval (SOLA) for use on protected leafy herbs.

Cultural
The source of the pest is usually either infested stock plants or weeds, hygiene procedures are key to avoiding or reducing infestations:


 * Maintain strict weed control in and around glasshouses and polythene tunnels.
 * Dispose of infested plants carefully.
 * Keep stock plants in a separate structure from those used for propagation or production.
 * Avoid taking cuttings from infested stock plants.
 * Yellow sticky traps may be useful in doorways or under vents, to catch adult leafhoppers flying from infested plants to ‘clean' plants. However, these will also catch flying beneficial insects, e.g. parasitic wasps, so they should be used and positioned with care.
 * On outdoor herbs, a suction machine was tested in 2008 for removing leafhopper from field crops. Results of this HDC-funded project is now available in the report for project FV 330.

Biological control
The following species can be used to control an infection of leafhoppers: A tiny parasitic wasp. The adult females lay their eggs inside leafhopper eggs in the leaf veins or petioles. These insect-pathogenic nematodes enter the leafhopper nymph through the mouth or anus and release symbiotic bacteria, which kill the leafhopper. A. nemorum and A. nemoralis are generalist predators, feeding on a range of small invertebrates. Larvae of the lacewing Chrysoperla carnea are used by some herb growers as part of their biological control strategy against aphids. C. carnea will also feed on other pests e.g. Cabbage whitefly, greenhouse whitefly, red spider mites and thrips.
 * Anagrus atomus
 * Steinernema feltiae
 * Anthocorid bugs
 * Chrysoperla carnea

Other
Cover a piece of stiff card with grease or contact adhesive and hold it above the infected plants while lightly brushing the foliage with your other hand. The disturbed leafhoppers should become stuck to the card and can then be disposed of.

Chemical control

 * Spruzit (pyrethrins plus naturally derived oil) is approved for use on protected and outdoor edible crops including herbs. Pyrethrins are harmful to many biological control agents, but only for a few days after application, thus can usually be used with care within IPM programmes.
 * Calypso (thiacloprid), is a neonicotinoid insecticide with a SOLA for use on protected leafy herbs. The product was shown to be effective against ‘sage' leafhopper on sage in HDC project FV PC HNS 245 (Cole, 2003). Its 14-day harvest interval limits its practicality on short-term herb crops, but it could be useful for end of season clean-up of the pest on stock plants (but N.B. the SOLA restricts use to between 1 April and 31 October).
 * Nicotine 40% shreds (smoke) is approved on protected herbs, and Stalwart and XL All Nicotine 95% (nicotine sprays) have SOLAs for use on protected leafy herbs. Nicotine has both contact and fumigant action and may give some control of leafhoppers. Its harmful effects on biological control agents only persist for 2-3 days after application, so nicotine can usually be used with care within IPM programmes.

Chrysanthemum/Sage leafhopper
(Eupteryx melissae)


 * Basil
 * Bergamot
 * French lavender
 * Lemon balm
 * Mint
 * Marjoram
 * Oregano
 * Rosemary
 * Sage
 * Thyme

Green leafhopper
(Empoasca decipiens)
 * Cucumber
 * Sweet pepper
 * Thyme

Glasshouse leafhopper
(Hauptidia maroccana)
 * Cucumber
 * Tomato

Potato leafhopper
(Eupteryx aurata)
 * Potato
 * Mint