The Department of Agriculture is investigating a tiny pest, the Staphylinid beetle, that may threaten cauliflower crops in the Manjimup area.

Department research officer Françoise Berlandier said this week the Department received the first report of the pest this season from a cauliflower crop west of Manjimup.

The beetle was first noted in the summer of 2001/2002 in crops on the Manjimup Horticultural Research Institute and on farms to the east and west of Manjimup.

Ms Berlandier said the insect damaged curds of the cauliflower by grazing on the surface, which resulted in a brown discolouration.

"The beetles are tiny insects from the family Staphylinidae that are three millimetres long and one millimetre wide, are dark brown or black, and have a habit of sticking their abdomen up in the air as they walk along rapidly," she said.

"Little is known about this insect, but it is suspected to be a native beetle that normally feeds on decaying plant matter, but the insects can become a pest when they move onto cauliflowers. They are winged and infestations could start either by adults crawling or flying into the crop. At this stage we know that they enter the crop to feed, but it is unlikely that they reproduce in the crop.

"Infestations are likely to begin when the insects increase in abundance in nearby breeding sites, and then move into a cauliflower crop under the right conditions.”

Ms Berlandier said early control was essential to prevent damage, as the discoloured curds caused by this pest would render a crop unmarketable.

Growers are encouraged to examine crops closely, particularly where wrapper leaves cover the curd or at the base of the plant, as the insects are likely to gather in these sheltered areas.

The Department has begun research to identify the optimum conditions for this pest, its distribution and breeding sites, while specimens will be sent to an expert in the USA for identification.

More information is available from the Department by contacting Françoise Berlandier at 9368 3249 or Stewart Learmonth 9777 0167.