Leafhopper speckling damage
Leafhopper frass on Fiesta fruit
Leafhoppers are minor pests of apple with a life cycle that involves overwintering as eggs and hatch in the spring to feed on the undersides of leaves causing speckling damage.
Very large populations of adults and nymphs can build up in apple orchards over a number of seasons if effective insecticidal control measures are not applied occasionally. Leaf speckling damage increases as the season progresses and can give the tree a bleached appearance by the end of the season. Intensive damage reduces vigour and fruit size and adversely affects fruit bud formation.
Fruit surfaces become contaminated by numerous small brown spots of excrement. This contamination is easily washed away by water, including by rain, during post-harvest drenching or grading.
Leafhoppers are small and usually green or yellow in colour and are easily distinguished from aphids as they readily jump and fly.
Leafhopper populations are best monitored by visual inspection for the characteristic speckling damage and for the leafhoppers themselves which are often present on the undersides of damaged leaves.
A spray of an approved insecticide should be applied in summer against adults and nymphs if leaf damage starts to become unsightly and is increasing.
- Acetamiprid (Gazelle), though only specifically recommended by the manufacturer for control of aphids, may give incidental control of leafhoppers.
- A full approval for spirotetramat (Batavia) on apples for the control of sucking insect pests will control leafhoppers, but growers may prefer to reserve its use for more difficult to control pests such as woolly aphid or rosy apple aphid. It must be applied after flowering and works best when pests are moving from brown wood to green tissue. It will prevent population build-up but does not offer pest ‘knockdown’.
- A recent EAMU for Flipper (fatty acids) has increased the available options should growers wish to reserve other insecticides for control of pests later in the season. Although recommended for control of aphids, mites and blossom weevil, it is expected to offer incidental control of leafhoppers when applied for these pests. It is known to complement the use of Batavia as it provides quick ‘knockdown’.
- Synthetic pyrethroids are also effective but they are harmful to the orchard predatory mite Typhlodromus pyri and many other natural enemies and should only be used as a last resort where no alternative can be used.
Control in organic orchards
Emphasis should be placed on cultural control methods.
- Fatty acids is permitted for use in organic production systems, but prior approval must be given by certification bodies before application.
Insecticides approved for use on apple which are recommended to control leafhoppers or offer incidental control when applied to control other pests
Choice of insecticides – efficacy factors
|Active ingredient||Trade name (examples)||Class||Selectivity||Approved for control of||Safety to Typhs|
|deltamethrin||Decis Forte etc.||pyrethroid||broad spectrum||Aphids, apple sucker, capsids, caterpillars, codling & tortrix moths, sawfly||harmful|
|dodecylphenol ethoxylate||Agri 50E||physical acting insecticide||broad spectrum||Aphids, leafhoppers, mealy bugs, spider mites||harmful|
|fatty acids||Flipper (EAMU 3419/19)||bioinsecticide||broad spectrum||Aphids, blossom weevil, two-spotted spider mite||unspecified but generally safe in IPDM programmes|
|spirotetramat||Batavia||tetramic acid derivative||selective||Sucking insect pests||unclassified|
|thiacloprid||Calypso||neonicotinoid||broad-spectrum, systemic||Rosy apple aphid. (Also likely to control capsids, leafhoppers, sawfly and weevils, though not caterpillars or woolly aphid)||safe|
Choice of insecticides – Safety factors
Read and follow the label before applying any sprays
|Hazards2||Harvest interval(days)||Max. no. sprays||Buffer zoneWidth (m)|
|Anticholin-esterase?||Humans||Fish & aquatic life||Bees|
|fatty acids||no||h, i||h||d||0||8||20|
|spirotetramat||no||h, i||t||u||Start of ripening||2||10|
|h=harmful, i=irritant, d=dangerous, ed=extremely dangerous, t=toxic, c=closed cab required for air assisted sprayers, u=uncategorised/unclassified/unspecified|