Crop Insects



Lucerne Flea

Sminthurus viridis



Adult lucerne flea (Smithurus viridis)
Agriculture Western Australia

Lucerne fleas usually spring from the plants when approached, using a special organ situated underneath the body. The lucerne flea is a dumpy looking and wingless creature of varied colour, but the larger specimens of 2 - 4 mm are predominantly green or yellow.

Life cycle
The first soaking autumn rains cause the special over-summering egg batches to hatch. Several generations may then develop over the growing period depending upon the weather. Eggs are laid in the soil and usually hatch in a few days. With the onset of warm and dry conditions in spring, the resting stage eggs, which are able to withstand summer conditions, are laid.

Damaged caused in young Lupins
Agriculture Western Australia

Pastures, legume crops and cereals may be seriously retarded by the lucerne flea and seedling death may occur in heavy infestations. Frequently the green leaf tissues are eaten, leaving a surface of the leaf as a whitish film. Severely affected areas appear, from a distance, to be bleached.
The lucerne flea is favoured by heavy soils and cannot live in very sandy situations. It is also dependent on plentiful moisture. Control in crops and pastures may be obtained with systemic or contact insecticides, as discussed under redlegged earth mite. A predatory mite, the bdellodes mite, is present over most of the area occupied by lucerne flea and exerts a useful level of control. Another predatory mite, the neomolgus mite, was introduced by the CSIRO and has been released at many places in the agricultural area. It will extend the area and level of biological control.