Kangaroo Island’s seed potato industry has adopted Integrated Pest Management (IPM) and the growers are reaping the benefits. This case study captures the story with insights from grower Peter Cooper and agronomist David Oddie.
“Before using IPM we were heavily reliant on chemicals” explains Peter, “We sprayed every 10-14 days, using a mixture of soft sprays and broad-spectrum chemicals, which meant we were killing beneficial insects and didn’t get the full value out of the soft products.” This approach was both costly and time consuming, but worst of all, it wasn’t providing adequate control of the most important pests in a seed potato crop – the aphids and thrips that vector leaf roll virus and tomato spotted wilt virus.
Both the growers on the island and their agronomists recognised that the approach they were using was not working, and in January 2015 they invited entomologists Dr Paul Horne and Angelica Cameron of IPM Technologies to run an IPM workshop.
Paul and Angelica introduced the group to the key beneficial insects in potato crops – including the predators and parasites of aphids, thrips, and potato tuber moth – and explained how these naturally occurring insects can help to control pests. They demonstrated how broad-spectrum foliar insecticides can cause pest flare when they knock out the natural enemies of pests, and explained how cultural controls (management practices) can be just as effective as chemical controls for certain key pests and diseases.
Paul and Angelica then helped the group to draw up an IPM strategy involving biological, cultural and chemical controls that were all compatible and would deal with the full range of pests. At the end of the workshop, several growers agreed to trial the IPM strategy, with the help of agronomists Derrick Cameron and David Oddie of DJ’s Grower Services.
When the demonstration trials got underway, Derrick and David provided regular monitoring support and advice, and IPM Technologies gave additional expert support as required. According to David, access to ongoing advice from experienced IPM specialists gave the growers confidence and helped reduce the risk of trying something new and unfamiliar.
The results of the trials were excellent. They achieved very good control of insect pests with only minimal use of ‘soft’ selective insecticides, and no broad-spectrum products were applied during the life of the crop.
In January 2016 Angelica and Paul visited the island again to hold a field day at Peter Cooper’s farm. They described to the group the IPM approach he had used and demonstrated how naturally occurring beneficial species were present and playing an important role in controlling the major pests.
The success of the initial demonstration trials gave other local farmers confidence to try IPM for themselves. In the 2016-17 season the majority of the island’s seed potato growers implemented IPM across their farms, and David expects that soon the entire Kangaroo Island seed potato industry will have adopted IPM.
Potato growers on the island were initially sceptical about IPM, but now they have seen it work and they understand what is involved. “Like most farmers, we used to think IPM is about not spraying and just hoping for the best” said Peter. “Now we know it is all about understanding good and bad insects and the effects of different chemicals on those insects. We still use insecticides when we need to, but we are more careful about the products we use, to make sure the good insects can still help protect our crops.”
The island’s potato growers are enjoying the benefits of IPM, which include reduced reliance on insecticides, better control of pests, and the time and cost savings resulting from reduced insecticide use. “We have cut down to only one or two applications of foliar insecticide per crop, and this year the only incidences of aphid problems on the island were in the crops where IPM had not yet been adopted, so we know that what we are doing is working” said David. Peter explained that although the soft selective insecticides are more expensive, there is actually an overall cost saving because he is applying less insecticides and spending much less time spraying. He has also noticed improvements in the level of pest control since shifting to IPM, particularly with regard to thrips.
The experience of growers on Kangaroo Island is one that IPM Technologies has seen repeatedly over many years, where confidence in IPM comes from first-hand observation in local crops. It also demonstrates that IPM can give better results even for growers with low tolerances for insect pests and associated insect-vectored diseases.