Integrated Pest Management (IPM) is a vital tool for controlling and managing pests, particularly in protected cropping, and continues to evolve. James Altmann, Co-Director, Biological Services at Loxton in South Australia, says in the past 20 or so years IPM has gone from an alternative method of pest control to mainstream. Among the factors driving the switch to IPM has been the failure of many chemicals due to insect resistance and a greater awareness of health and safety.

IPM uses all forms of pest control including quarantine and hygiene, cultural controls, varietal selection for pest or disease tolerance, beneficial insects and mites, as well as selective chemical controls.

Five steps to switching to beneficials

By relying on beneficial insects, mites and pest-specific chemical controls, growers are reserving other chemicals as an absolutely last resort for pest control. “Without preserving chemicals in this way,” James warns, “we won’t have them in the future as pests are rapidly building up resistance and not as many new chemicals are being developed.”

James has five important steps for implementing an IPM program in a protected cropping environment and it is particularly important to avoid scheduled spray programs.

Step 1 Utilise seedlings or other propagating material that does not have pesticide residue that is toxic to beneficials. Speak to your nursery about what chemicals have been used in production.

Step 2 Identify likely key biological control agents for your crop and introduce them early in the crop cycle.

Step 3 Monitor crops for pests and beneficials.

Step 4 When sprays are required, use those that are specific to the pest and which preferably do not harm beneficial insects.

Step 5 Avoid wherever possible residually toxic broad-spectrum chemicals.

What’s new in IPM

New predators are under trial to deal with pest problems in nursery, vegetable and fruit crops. A recent and exciting breakthrough has emerged in the shape of a small native beneficial mite called Typhlodromalus lailae. This beneficial is currently under trial in protective cropping situations against thrips, whitefly and pest mites.

“This beneficial has been recognised for many years but was difficult to rear in the lab in large numbers,” says James. “T. lailae is a native Australian predatory mite naturally present in many mild, humid, coastal and hinterland districts.

“In 1998-2000, NSW Agriculture entomologist Marilyn Steiner, recognised its potential as a biological control agent for greenhouse cropping, due to its voracious appetite for thrips, whiteflies and some eriophyid mites but, as it was difficult to raise, it fell off the radar.”

A chance re-discovery of T. lailae has re-ignited interest in Marilyn’s work. This time, a viable method to build up numbers has been established.

“What we couldn’t achieve 20 years earlier when we first attempted to breed T. lailae is now possible as our facilities and skills have advanced,” explained James.

With predator rearing under control the next stage was to trial it on farms and against a wide range of common pests.

“We are now running active field-trials to test whether the mite could become a new option for commercial growers in mild to humid regions of the country and in greenhouse-grown crops,” James said. “Optimum temperatures are likely to be 15-30C but T. lailae can continue breeding at 7-8C and it can survive 0C, which makes it a good candidate for overwintering in outdoor crops. The mites do not like very hot dry environments but persist at higher temperatures if humidity levels are good.”

The mite is closely related to T. limonicus, an important predator used in Europe for thrips and whitefly control in greenhouse vegetables, flowers and ornamental crops. Dr Jenny Beard from the University of Queensland is investigating the possibility that T. lailae and T. limonicus may in fact be the same species added James.

“When we discovered we had T. lailae in culture, we got in touch with Marilyn Steiner who originally recognised the value of this predator. We managed to coax her out of retirement and she is monitoring a commercial trial in her area – a crop of cucumbers at Family Fresh Farms in New South Wales for thrips and whitefly control.”

Trials for new biological control

He also reports that trials with T. lailae have begun across the country and include Zalsman Capsicums (for western flower thrips) and T&L Avocado Nurseries (six spotted mite/whitefly) both in Western Australia, and Nood Bloom Roses (western flower thrips) in Victoria.

Paul Horne of IPM Technologies is also trialling T. lailae for tomato russett mite and other pests in ornamental plants. Dr Steve Quarrell (Tasmania) and Cindy Edwards (Victoria) are looking at red berry mite and broad mite control in blackberry and raspberry crops.

A trial is also being undertaken on capsicums in Western Australia to test the effectiveness of T. lailae on tomato potato psyllid (TPP), as previous research in New Zealand shows that T. limonicus feeds on the eggs of TPP.

While it is early days, the trials have revealed that the mite is performing so well especially in cucumbers, capsicum and nursery crops, it is likely we will have a new product in IPM in the next few months says James Altmann from Biological Services.

Conference workshop for IPM skills

James Altmann and staff from Biological Services are keen to share the skills they have honed in pest and predator identification with growers. They will be taking part in a hands-on IPM workshop during the Costa PCA Conference, July 7-9, on the Gold Coast. In the workshop delegates will be able to learn how to use a hand lens to identify common pests and how to recognise the beneficials that control them.

by Jennifer Stackhouse