Aspects of integrated control of the carrot rust fly (Psila Rosae Fab.): Controlling the pest with less insecticide: A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Horticultural Science with Honours at Lincoln University

Abstract

The carrot rust fly (Psila rosae Fab.) is a significant pest of carrots worldwide and is capable of causing severe damage to this and other crops in the Apiaceae. A field trial based in two commercial carrot crops, both involving carrots for processing by Heinz-Wattie Ltd, took place during the 1996-97 season. The protocol of the experiment was for the field to be divided in half. One half of the field was to receive half rate of the insecticide at the outer margin of the crop only, with the remaining half of the field receiving recommended label rates over the entire field half. Insecticide was applied according to protocol in one carrot crop. The second crop received half rate of the insecticide at the outer margin of the crop for the entire field. This deviation from the experimental protocol did not allow a traditional statistical comparison between treatments, as the deviation removed replication from the field trial. Adult fly populations were monitored with transects of yellow sticky traps that were changed at weekly intervals. Roots were sampled immediately prior to commercial harvesting of the crops to assess the damage caused by feeding larvae. Numbers of third generation flies caught were greater than those caught during the second generation. However, numbers were too sparse to compare for statistical differences between the different insecticide treatments. There were no significant differences in the number of mines per root or the severity of larval damage between the two different insecticide treatments. Technology transfer that has developed from the results of the commercial field trial and from previous research conducted at Lincoln University are discussed. Particular mention of the grouping and. interactions of Lincoln University, the New Zealand Vegetable and Potato Growers' Federation Inc. (Vegfed) and Heinz-Wattie, collaborating as an agricultural network are outlined The three agricultural network components, which contributed to the creation of a technology transfer 'package' for the integrated control of the carrot rust fly are: network members, research component and communication component. These components and the specific outputs of the project are discussed