Apple pesticide use may be cut 30 p.c.

Press, 22 June 1989, Page 25

Apple pesticide use may be cut 30 p.c.

PA Wellington Pesticide use in the apple industry could be cut at least 30 per cent as a result of research into safer methods of pest control. D.S.I.R. studies show apple growers need to spray insecticide against only their chief pest, the leaf-roller moth, when it is known to be in the orchard.

The low-pesticide method will be tested in 15 orchards throughout New Zealand next season and it is hoped it can be in general use within two seasons.

Dr Jim Walker, head of a D.S.I.R. Entomology Division research team in Havelock North, said a 30 per cent cut in insecticide spray was possible by the use of D.5.1.R.-developed sex pheromone traps for the leaf-roller moth.

Sex pheromones released into the air by female moths are powerful lures to male moths

and, when incorporated into a trap, can be used to catch them. Female moths then are not mated and caterpillars, which do the damage in the orchard, are not produced. D.S.I.R. scientists are also working on other methods of pest control. One technique, the disruption of the mating behaviour of moths, is also based on the use of sex pheromone. Synthetic sex pheromone is used to confuse male moths in their attempts to find female moths for mating. The technique is now being studied on 25ha of apple orchards * in Hawke’s Bay and Nelson.

Dr Walker said initial results were promising. He predicted Nelson orchardists would be using the mating disruption widely by 1992. The department was also looking at ways of making less hazardous in-

secticides. He said the ultimate aim was to isolate a new and potent form of bacteria which would work against the leafroller moth.

A group of scientists representing a wide range of disciplines has been formed to look at reducing New Zealand’s dependence on pesticides. The Ministry of Agriculture’s researchers are from areas as diverse as immunology, apiculture and organic chemistry, and will study ways which reduce pesticide use to a minimum, without sacrificing crop quality. A MAFTech plant protection research leader, Dr Rod East, said researchers would look at developing biological controls, learn more about the basic biology of important pests, weeds and diseases, and make greater use of environmentally “soft” pesticides.