AVENGING THE APHID INTEGRATED PEST MANAGAGEMENT Integrated Pest Management (IPM) is becoming an increasingly popular method for farmers to manage insects more sustainably. The mainstays of IPM are the use of cultural and biological controls with chemicals being used in more of a supportive manner.
CASE STUDY
Flowerdale grower Rob Sadler has been investigating a new IPM approach to combat aphids in his lilies. Rob produces around 270,000 bunches of lilies per year which need to be beautifully presented, however aphid damage can render the flowers unsightly and unsaleable. Aphids distort the leaves and the growing flower buds by feeding on the foliage. After many seasons fighting a losing battle against these small but destructive pests Rob decided to reconsider his management approach. “We had done a big spray program previously with a lot of insecticides and we found we were getting resistance, so we had to find a new method to control them”. At the time, Rob was relying exclusively on insecticides at scheduled application times for control. During high pressure periods, this was almost at weekly intervals. The scheduled spraying and broad-spectrum insecticides included in his program meant that naturally occurring aphid predators such as lacewings and wasp parasitoids were able to neither establish nor survive.
“..We probably cut our insecticides by half and we got control…”
Rob received support and expert advice from Dr. Paul Horne and Jessica Page from IPM Technologies to revise his pesticide program with the aim of building up the population of beneficial insects in his crop. They also provided information about the life-cycles of these predators and how to monitor for them. According to Rob the first step in making a change to IPM was “having someone come on to my farm and teaching me what’s what. What are the predators/beneficials, where do I look to see if they are there or not”. The modified spray program included only two scheduled insecticide sprays, applying “soft” aphid specific chemicals early. If through monitoring, there were concerns about aphid populations building up an additional soft spray could be used. The main reliance however would be on the biological controls. Rob applied this programme to his entire farm including both his outdoor and covered crops. There were some ‘keep the faith’ moments in the beginning for Rob. It was a big learning curve and he had to hold back from applying insecticides as he was accustomed to. “We were doing twice the crop walks this season, monitoring down to a minute level, looking for lacewing eggs and parasitised aphids.” To his relief, it all paid off. By implementing these IPM strategies, Rob successfully controlled the aphids, in his outside crop at least. “In the covered crops we started using ‘soft’ chemicals but later in the season the pressure got too high and we had to use some knockdown chemistry.” He did however use significantly less insecticides than in previous years. “We probably cut our insecticides by half and we got control.”
Lily producer Rob Sadler on his farm in Flowerdale