Journal of the Department of Agriculture, Western Australia, Series 4


M M H Wallace


Halotydeus destructor, Sminthurus viridis, Insect control, Seed treatment, Insecticides, Western Australia

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THE red-legged earth mite, Halotydeus destructor (Tuck.), and the lucerne flea, Sminthurus viridis (L.), are at present controlled effectively, cheaply and safely by a combined DDT/malathion spray (Jenkins, 1956, 1957) and this continues to be the general recommendation for farmers.

However, this combination has some disadvantages. The DDT in the spray ensures some residual control of the earth mite but has the unfortunate property of toxicity to the bdellid mites which are useful predators of the lucerne flea.

The malathion in the spray assists the DDT to control the earth mite and provides a good, quick kill of the lucerne flea, but it has no residual action.

As a consequence, lucerne flea populations tend to build up again rapidly after treatment, unless a second treatment is applied.