Usually only a pest in Northland, South Auckland, Waikato and the Bay of Plenty
Small (>1 mm) yellow/green insects that jump when disturbed
Clover flea will feed on a range of legumes but white clover is the preferred food plant
Damage can also be caused to lucerne, subterranean clover and when numbers are very high to grasses
Damage is caused primarily in spring and autumn.
Biology
Clover flea is a misleading term as they are not fleas at all and indeed may not even be insects. They are a type of Collembola commonly known as globular springtails. This name derives from them appearing to consist of 2 attached balls (hence globular) and a specialised appendage which enables them to spring very quickly into the air (hence springtail and flea). The same animal is also known as lucerne flea. Clover flea is present throughout New Zealand only reaching pest status in localised areas of the North Island – dairy pastures in parts of Northland, South Auckland, Waikato and the Bay of Plenty
After mating female clover fleas lay their eggs in batches of 2 – 40. These usually hatch after 26 – 42 days depending on temperature. Eggs laid in late spring take longer to hatch and will not do so until they have undergone periods of dry conditions followed by declining soil temperatures and increasing soil temperatures. This avoids the eggs hatching during dry summer months when food may be scarce. After hatching the young clover flea passes through 7 moults increasing in size each time until they reach a maximum size of about 3mm. Females tend to be larger than males but both are yellow green in colour with brown mottling on their backs. The adults live for approximately 15 days during which time males and females mate and egg laying starts again.
Impacts
Impact to pasture
Clover flea is present throughout New Zealand but severe damage only occurs to dairy pastures in localised areas of the North Island – parts of Northland, South Auckland, Waikato and the Bay of Plenty
Clover flea will feed on a range of legumes but white clover is the preferred food plant in New Zealand. Damage can also be caused to lucerne, subterranean clover and when numbers are very high to grasses
Damage to clover results from young nymphs eating small holes in the leaves, giving the leaves a speckled appearance, while feeding from older nymphs and adults produces window like openings in the leaves. In cases of heavy infestation only the veins and cuticle of the clover leaf remain
Pasture damage is caused in late spring when high numbers of nymphs and adults can be present
Numbers of nymphs and adults are lower during summer, when mainly eggs are present, but increase again in autumn when again damage can occur
Pasture production losses of up to 20% frequently occur and reductions in clover yield of up to 50% have been recorded
Compounding direct feeding losses is that stock will avoid eating pasture fouled by clover flea faeces.
Control
Chemical control
Several insecticides are registered for use against clover flea (see below) and both spray and granular formulations can be successfully used. Applications should be applied when damage is first noticed or when high numbers of clover fleas are observed. At times repeat applications may be necessary to achieve good control. In this situation the most cost effective approach can be to use diflubenzuron in conjunction with another insecticide
Registered insecticides (active ingredients) for use against clover flea in pasture or clover seed crops are: chlorpyrifos, diazinon, diflubenzuron, dimethoate, fenitrothion and maldison
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