Integrated control of apple pests in New Zealand 1. Outline of experiment and general results

Abstract

Experimental details for 1962–73 are given of an investigation into integrated control in an apple orchard near Nelson. These include a description of the orchard, crop records from several representative cultivars, incidence of pest damage, and information on the biology of the pests and their natural enemies. An integrated programme based on fungicides (but no lime‐sulphur), with ryania as the main insecticide, was compared with a standard programme of fungicides including lime‐sulphur, an insecticide schedule based on azinphos‐methyl applied eight or nine times each summer, and acaricides. The standard programme gave good control of insect pests, but Panonychus ulmi remained a recurring problem. Later, where the standard programme was used but specific acaricides were omitted, Typhlodromus pyri resistant to azinphos‐methyl became established. With the integrated programme, biological control of P. ulmi and Eriosoma lanigerum was achieved, and Edwardsiana froggatti was controlled by ryania. Control of Laspeyresia pomonella was inadequate in the early years, but improved later following attention to orchard hygiene and study of the optimum use of ryania, including method of application, timing, and formulation. The Australian Epiphyas postvittana was the most harmful pest within the integrated programme, despite mortality caused by ryania and a number of parasites; collecting in Australia produced more parasite species, some of which were reared and released. The orchard habitat was diversified by planting Acacia spp. and Citrus spp., to increase the survival of adult parasites. Quad‐raspidiotus perniciosus was scarce at the start of the experiment, but increased steadily with the integrated programme, and spraying with mineral oils became necessary. Other methods of controlling lepidopterous pests being investigated include the use of low‐dosage azinphos‐methyl and carbaryl, Bacillus thuringiensis, and viruses. If successful, some of these methods would replace ryania in the integrated programme.