Aphids are a frequent pest of canola, occurring in autumn with warm temperatures and good rainfall supporting rapid population growth. Green peach aphids (GPA) tend to attack canola crops during this time. GPA deprive the plant of nutrients and promote sooty mould growth, but more importantly, GPA is known to transmit plant viruses such as beet western yellow virus.
Depending on climatic conditions, aphids may also re-infest crops in spring, during the critical flowering-podding period, with cabbage aphids generally the primary pest during this phase of crop development. An aphid infestation combined with moisture stress at this stage may quickly lead to crop failure.
Transform controls a wide range of sucking pests, giving rapid knock-down, with the first symptoms in affected pests often observed approximately 20 minutes after application. This rapid knockdown of aphids contributes to a lower incidence of viruses in crops sprayed with Transform.
Integrated Pest Management (IPM), where all management tools are exploited, including use of predators and parasites, should be encouraged as a natural way of curtailing aphid numbers. However, if more than 20% of plants are infested with aphids, an insecticide is required to avoid crop losses (Agric WA). Using an IPM friendly insecticide is essential to achieving the best possible yield. Numerous studies have demonstrated Transform to be soft to beneficial insects such as predatory beetles, predatory bugs, parasitoids, lacewings and spiders. These beneficials keep aphid numbers in check and extend the period required between insecticide applications.
Applications of Transform in flowering canola must be carried out early in the morning or in the evening, when bees are not foraging in the crop. Transform is only toxic to bees by direct contact; once spray deposits are dry any effects on bees is negligible. At other stages of crop development, Transform can be applied at any time of the day.
Transform should be used at the full label rate (48 g/ha) as applying lower rates facilitates the development of resistance in the population. Green peach aphid has shown widespread resistance to many groups of insecticides, including pyrethroids, organophosphates and carbamates in southern Australia. As with all insecticides that target aphids, Transform should not be used in consecutive sprays; and while a maximum of two applications is allowed to any canola crop, an alternate mode of action must be applied between Transform treatments.
Transform is effective in both warm and cool conditions. It works both by contact at the time of application, and is translaminar and systemic within the plant. Ingestion of Transform by feeding aphids will provide control for up to 14-21 days after an application.
Transform is highly compatible and may be applied with a range of other insecticides or late foliar fertilisers. It is easy to use as it can be aerially applied and it’s short 14 day harvest withholding period makes it ideal for use later in the season.
Transform is now available as a water dispersible granule (WG) formulation. This makes it stable for an extended period. Transform WG is more than double the concentration compared to the previous soluble concentrate (SC) formulation. Growers may pick up a 5 kg pack of Transform WG, which contains enough product to cover 100 ha of canola. This pack is easier to transport, store and use than was the old 20 L pack of liquid Transform Insecticide.
Where aphids have arrived late in the season, Transform is a perfect solution to ensuring the best possible return on investment. For more information, please contact your local Dow AgroSciences representative on 1800 700 096.
Update on Russian Wheat Aphid
Dow AgroSciences has not conducted any biology work on the Russian wheat aphid (RWA) biotype currently discovered in Australia. Transform has been trialled in the USA against RWA and has demonstrated efficacy on this pest; however, label rates for Australia have not yet been confirmed. The USA trial work suggests chlorpyrifos is the most effective product on RWA followed closely by Cobalt™ Advanced.
In the absence of local data, Dow AgroSciences supports the APVMA permit recommending a 500 gai/L chlorpyrifos based product, such as Lorsban™ 500 EC, to manage this pest. A rate of 600 mL/ha may be used for control of RWA. Dow AgroSciences supports the use of a crop oil concentrate, such as Uptake™ Spraying Oil, for this use; but cautions against mixes with Li700 due to potential crop effects.
Regardless of the insecticide used, spray coverage will be crucial to achieve the best result. Water rates must be high enough to ensure adequate leaf coverage of the crop. RWA tends to curl the leaves of affected plants, so use very early in the crop (prior to leaf curl) will give better results.