Trials for controlling pest and disease in custard apple by using exclusion netting (CU03004)

This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

The Australian custard apple industry was keen on finding alternatives to the use of insecticides for control of insect and vertebrate pests of custard apple. A separate project conducted with netting of low chill stonefruit had shown that birds, bats, Queensland fruit fly and a number of other pests in southeast Queensland could be controlled by netting stonefruit trees and physically excluding such pests. Chemical control was therefore not warranted, and there were several other advantages, such as better fruit quality and reduced water use in the netted blocks. No Queensland fruit fly had been trapped within the netted block.

This concept was transferred to custard apples at Alstonville in New South Wales. At the netted site it had been estimated that custard apple fruit losses from fruitspotting bug (Amblypelta sp.) had reached as high as 50 per cent in bad seasons.

The project was funded solely to erect netting and associated infrastructure over an area to be planted to young custard apple trees. In addition, the structure was designed to incorporate a novel tree training system (Open V-trellis), with which it was hoped to improve the efficiency of growing custard apples, and to reduce labour involved in growing and harvesting custard apples.

The overall effectiveness of netting for custard apple pest control, and the advantages and disadvantages of the Open V-trellis system was evaluated in a subsequent project. The netting project simply focused on setting up a netted block for such future work.