Some studies of the cholinergic systems in Costelytra zealandica (White) and Caloglyphus berlesei (Mich.)

Abstract

The grass grub, Costelytra zealandica (White), is New Zealand’s principal pasture pest. The larval stage of this insect dwells in the soil and feeds on the roots of pasture plants, being most active over the period March-July in Canterbury. During this period, damage may occur to such an extent that grasses may largely disappear from heavily infested areas. Control measures have involved the application of DDT although from June 30, 1970, the use of this insecticide on pastures has been prohibited. A search has been made for alternatives to DDT and a number or organosphosphorus insecticides – which are less persistent than DDT – have been subjected to biological screening. During this work it became clear that a study of the effects of some of these materials on grass grub and grass grub beetle acetylcholinesterase was very desirable. Preliminary steps taken in this direction are reported here.

A study has also been made of the cholinergic system in the granary mite, Caloglyphus berlesei (Mich.). This mite, which is a pest of stored foodstuffs, shows a particularly low susceptibility to organophosphorus acaricides.