Helpful insects abound

A NSW DPI scoping study of beneficial insects for the Riverina Plains Farming Systems Group found 91 different beneficial species in the sampled 10 paddocks of wheat, triticale, canola and lucerne pasture.

Sampling in March, July and November 2006, Dr Joanne Holloway of NSW DPI found that of the 91 beneficials, 47 were wasp species.

They deserve the tag "beneficial" for being either predatory or parasitic on other species, particularly pests.

"The highest numbers of wasps were found in lucerne pastures, probably as a response to aphid swarms," Dr Holloway, a research entomologist based at Wagga Wagga Agricultural Institute said.

"In all paddocks spiders, which use a range of hunting techniques to predate on pests, were among those groups with the highest numbers.

"As with most other beneficial species, spider numbers were highest in November.

"Canola crops recorded the highest number of spiders."

Seven species of beetles, adults and/or their larvae, were found. Other beneficial species found included predatory bugs, flies, lacewings, earwigs, mantids and mites.

Plant Health Sciences Research Unit