Pest and disease factsheet - Leafhoppers, capsids & suckers

More bugs surviving warmer winters can cause problems for nursery stock.

Leafhoppers, capsids (including shield bugs), froghoppers, lacebugs and psyllids all belong to a huge order of insects — Hemiptera, or true bugs.

They have piercing and sucking mouthparts and hardened forewings that form a protective shield when folded over the abdomen. Damage is caused by wounding and from toxins in the saliva. It can show as foliage distortion, discolouration and bleaching as well as producing ragged holes on young growth, rendering plants unsaleable.

Psyllids, including box and bay suckers, can foul foliage with honeydew, leading to extensive sooty mould growth. Rhododendron leafhopper may transmit the fungal disease bud-blast. Adult capsids also feed by grazing leaf and bud tissue. Winter survival is by eggs or as adults, depending on pest type.

These bugs are a problem in nursery stock because of larger numbers of overwintering eggs or adults surviving warmer winters and the high degree of selectivity of modern pesticides, which target the more serious pests, leaving ecological niches to be filled by species once regarded as insignificant.

How to recognise them

Leafhoppers Resemble elongated aphids, 3-10mm long. If disturbed, they jump and fly briefly before resettling. Rhododendron leafhopper has red bands on green wing cases.

Capsids Adults are pale-yellow, green or brown, up to 6mm long with hardened forewings, long legs, antennae and proboscis. Nymphs are wingless. Capsids are hard to spot, tending to drop to the floor or fly at the slightest disturbance.

Shield bugs Adults can be up to 10mm long with nymphs and adults usually different colours. Common green shield bug (Palomena prasina) is native. Southern green shield bug (Nezara viridula) is a recent UK introduction and can be 12mm long.

Froghoppers Up to 6mm long, frog-like, with prominent eyes and powerful back legs.

Pale-coloured nymphs feed protected by frothy "cuckoo-spit". Red and black froghopper (Cercopis vulnerata) has striking markings.

Lacebugs Ornate lace-like wings on adults up to 4mm long with brown/black bodies. Nymphs are usually yellow. Although they have wings, they do not fly. Platanus lacebug (Corythucha ciliata) is notifiable.

Psyllids Adults 2-3mm long with two pairs of wings. Nymphs (or suckers) have wide, flattened bodies and prominent eyes and wing buds.
 
Biology

Common green capsid (Lygocoris pabulinus) Lays eggs on woody twigs in autumn. These hatch in spring and nymphs feed on new growth before migrating to herbaceous hosts in summer where females mature and lay second-generation eggs.

Glasshouse leafhopper (Hauptidia maroccana) Can breed all year round in heated greenhouses. Inserts eggs into leaf veins. Nymphs hatch after one-to-four weeks and mature to winged adults in one-to-two months.

Rose leafhopper (Edwardsiana rosae) Lays eggs in tissue of shoots in autumn that hatch from May onwards. Nymphs mature to adults by July, laying second-generation eggs into leaf tissues that hatch August-September, resulting in second-generation adults that lay overwintering eggs.

Lace bugs Adults appear in early summer and feed until autumn, when they lay eggs along the midrib of leaves. These overwinter and hatch the following spring.

Psyllids Can attack a range of plants including Buxus, Crataegus, Elaeagnus, Laurus, Malus and Pyrus, inducing leaves to curl over feeding sites as protection. Nymphs also produce protective woolly wax. Psyllids secrete honeydew and can overwinter in curled leaves on the plant or in leaf litter.

Treatment: biological control

Parasitic wasp Anagrus atomus lays eggs into the eggs of glasshouse leafhopper. After a few days, the egg turns red as the parasite develops. It eventually turns brown and the adult wasp emerges. Life cycle takes 12-20 days at 25-16°C. Use at first sign of damage. Generalist predators such as Chrysoperla (lacewings), Coccinella (ladybirds) and Macrolophus will eat sap-sucking bugs.

Treatment: cultural control
• Install yellow sticky traps over vulnerable crops.
• Remove leaf debris and other potential overwintering sites.
• Control weed hosts including chickweed, dead-nettles, mayweeds, sow thistles, bindweeds, dandelion, fat-hen and others.
• Hedgerows may be a source of predators such as lacewings. Wild rose in hedgerows is a natural source of Anagrus atomus.
• Monitor regularly for eggs and nymphs. Capsid damage may only be visible three days after feeding starts.

Treatment: chemical control

Active ingredient Cypermethrin
IRAC code 3
Formulations Various including Toppel 100* (United Phosphorus)
Action(s) Contact and stomach-acting synthetic pyrethroid insecticide. Good coverage is essential. Not compatible with biological control.

Active ingredient Deltamethrin
IRAC code 3
Formulations Various including Decis (Bayer)
Action(s) Contact, synthetic pyrethroid insecticide with residual activity. Not compatible with biological control.

Active ingredient Chlorpyrifos
IRAC code 1B
Formulations Various including Dursban WG (Dow)
Action(s) Contact and ingested organophosphorus insecticide. Short persistence on some biological controls but not all.

Active ingredient Indoxacarb
IRAC code 22A
Formulation Explicit*, Rumo* or Steward* (DuPont)
Action(s) Acts by ingestion and contact.

Active ingredient Lambda-cyhalothrin
IRAC code 3
Formulations Various including Hallmark with Zeon Technology* (Syngenta)
Action(s) Contact and residual synthetic pyrethroid insecticide. Not compatible with biological control.

Active ingredient Petroleum oil
Formulation Spraying Oil (Certis)
Action(s) Insecticidal oil that acts by physical means. For dormant-season use. May have some effect on overwintering eggs. Good contact with the target pest is important for efficacy.

Active ingredient Physical pest control
Formulation SB Plant Invigorator
(Stan Brouard)
Action(s) Contact insecticide with physical action — good coverage essential. Label restrictions apply. Take care when using with biological control.

Active ingredient Thiacloprid
IRAC code 4A
Formulation Calypso* (Bayer)
Action(s) Neonicotinoid, systemic product. Foliar applications are not compatible with biological control.

Fully updated by Dove Associates.
* Extension of Authorisation for Minor Use (EAMU) required for use in ornamental plant production outdoors and/or under protection.
Use plant protection products safely. Always read the label and product information before use.
Dove Associates shall in no event be liable for the loss or damage to any crops or biological control agents caused by the use of products mentioned.


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