An assessment of five spray regimes against a population of codling moth Carpocapsa pomonella (L.) : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Agricultural Science with Honours in the University of Canterbury [Lincoln College]

Abstract

The codling moth, Carpocapsa pomonella (L.) is principally a pest of apples but can also attack many other fruits.

In New Zealand, the spray programmes utilised in commercial orchards meet with almost 100% central but the materials applied, e.g. a simphos-methyl , are monoselective and therefore kill beneficial species along with the pest.

From 1962 onwards, a modified spray programme has been applied at Appleby Research Orchard, Nelson, New Zealand, with the objective of integrating chemical and natural means of control. Only selective pesticides have been applied and the botanical insecticide ryania was chosen to act against the codling moth. The utilisation of this insecticide was necessary because the natural enemies of the codling moth are generally unable to induce a population decline. Ryania , however is not particularly toxic and any attempt to increase its effectiveness would appear worthwhile. Few attempts have been made.

The effects that manipulated mortality factors, e.g. insecticide application, trapping, and cultural practices, have on a single generation of an insect can be conveniently illustrated by a single life table.

Continuous sampling of the codling moth adult, under New Zealand field conditions, can impart valuable information as to the period when the codling population is most responsive to insecticidal application.

Bait, light, and possibly pheromone traps can impart this information and of these three sampling methods the light is the more efficient, but also the more expensive.

The main objective of the work recorded in this thesis was to determine, by field experimentation, if increased mortality in a codling moth population resulted when specific adjunctives were added to ryania. A subsidiary objective of this work was to construct life tables for each spray regime and to use such tables to assist in interpreting the results of the spray trial.

A further aim was to conduct trials in an attempt to improve the efficiency of baited traps by using reflected colour.