A biological control agent, effective against one of the worst horticultural greenhouse pests, western flower thrips, is now under commercial development in response to big demand from growers.

"The effective agent, a tiny predatory mite affectionately known as ‘Monty’, is being used to bring this pest under control, particularly in cucumber crops grown in greenhouses," research scientist, Dr Leigh Pilkington, said.

Based at the Gosford Primary Industries Institute, Dr Pilkington said biological control agents like Monties were a boon to growers, because they were cost effective and led to less pesticides in the food chain.

"If we can use a biological control that does a good job and is cost-effective, we can reduce our reliance on chemical options, make our crops healthier and help improve production levels for cucumbers and a selection of other vegetables as well," Dr Pilkington said.

NSW Department of Primary Industries (DPI), in collaboration with two private entities, one in Queensland and the other in NSW, is now endeavouring to produce commercial quantities of the mite.

"The initial method of breeding them at Gosford for a small number of growers was highly labour intensive," Dr Pilkington said.

"Everybody who uses Monties wants to use more and demand has rapidly increased as news of their success precedes them."

Former researchers of NSW DPI at Gosford, Marilyn Steiner and Stephen Goodwin, now retired, discovered "Monty" - Transeius montdorensis.

Their chief supporter at the institute, Dr Pilkington had seen seeing the success of an army of millions of the tiny stormtroopers his team sent into battle against western flower thrips - but the success was conditional.

"As long as farmers can rid their greenhouses of pesticide residues that can harm this mite and other beneficial insects, Monties are highly successful," Dr Pilkington said.

"In future, farmers using Monties will have to use compatible pesticides, and limit or stop their use of broad spectrum pesticides."

Dr Pilkington said many farmers using Monties were also using other biological controls such as other predatory mites that target fungus gnats effectively under the surface of the soil.

"Complementary biological controls can be used just like compatible pesticides," Dr Pilkington said.

"While Monties target western flower thrips on the leaves, for example, there is a predatory bug being developed that may help target the same pest within the flowerbuds and help the Monties out as a close ally.

"Monties are now produced with much more efficiency after developing a rearing method with the two private organisations."

Dr Pilkington said using Monties also saved greenhouse workers from having to wear personal protective equipment in an already hot work environment that could reach higher than 35 degrees Celsius in summer.

"Growers can also be more specific in the application of the control," he said.

"They can see Monties at work in their crops just by turning over the leaves and monitoring their populations of biologicals as part of their routine inspection for pest numbers.

"By reducing their reliance on chemical management, the efficacy of these pesticides can be reserved for when they are really necessary."

Growers could also practice exclusions of pests in greenhouses by screening any vents, and taking care in their movements on the farm to ensure they were moving from a clean area to a clean area or clean to dirty.

Horticulture Australia Limited has funded the rearing program with a contribution of $180,000, nested within a wider project worth approximately $750,000 over three years.

NSW DPI encouraged farmers to get involved with commercial consultants, and DPI staff will make continuous visits to farmers to support the program.

Trials are also underway at the Institute, which is the NSW Centre of Excellence for Horticulture and Greenhouse Research, to look at other species which could combat greenhouse white fly and two spotted mite.

Contact Leigh Pilkington, Gosford, (02) 4348 1953, leigh.pilkington@dpi.nsw.gov.au

Further reading

Which thrips is that?

Western flower thrips (WFT) insecticide resistance management plan