Evaluation of insecticides against the larval stages of the Argentine stem weevil, Hyperodes bonariensis Kuschel (Coleoptera: Curculionidae) on wheat : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Agricultural Science in the University of Canterbury [Lincoln College]

Abstract

With the increased recognition of the Argentine stem weevil, Hyperodes bonariensis Kuschel, as an important pest of pastures, cereal and brassica crops, and in the absence of any known biological control agents in New Zealand, the use of insecticides may provide a practical means of combating this insect. With this point in mind, Buchanan(1966) screened a number of contact insecticides for their effectiveness against the adult weevils.

There were two main objectives in carrying out the present investigation. One was to supplement the work of Buchanan(1966) by studying the systemic action of a number of insecticides against the larval stages. Since the larval damage is the major cause of losses in crops and pastures, and complete control of the adult weevils with contact insecticides is difficult to achieve under field conditions, effective systemic insecticides may provide a better control of the weevil by killing the larvae within the plant stems. Moreover, many systemic insecticides have contact and vapour toxicities which might also kill the adult weevils. After finding an effective systemic insecticide, the next step would be field evaluation of this material. This would be necessary before any recommendation for general use could be made.

The other objective was to gain information so that it could be applied in work of a similar nature to be carried out upon the author’s return to his country. The techniques and the results of the present investigation would provide an introduction to work against the larvae of rice stem borer, Schoenobius bipunctifer, one of the most serious pests of rice in Burma.