While neonicotinoid resistance has been detected in green peach aphid in Australia, you won’t experience complete control failures…yet.
Green peach aphid (Myzus persicae, GPA) in Australia is known to have resistance to four different chemical groups – synthetic pyrethroids, organophosphates, carbamates, and now neonicotinoids. But the type of resistance is not the same for each chemical, and this matters for control efficacy. There are two main types of insecticide resistance that GPA populations can develop: target-site resistance and metabolic resistance.
Target-site resistance is the real baddie as it results in complete insecticide ineffectiveness and control failures. This is the type of resistance that GPA has developed to synthetic pyrethroids (e.g. alpha-cypermethrin) and carbamates (e.g. pirimicarb). Metabolic resistance, on the other hand, is the lesser of two evils. When a population acquires this type of resistance, they have the ability to detoxify the insecticide and make it less effective. We have seen GPA develop metabolic resistance to organophosphates (e.g. dimethoate) and more recently, neonicotinoids (e.g. imidacloprid).
Phew! So, the type of neonicotinoid resistance detected in GPA is not the worst-case scenario. Does that mean we can be complacent and go on with business as usual?
In a word – no.
Target-site resistance can develop in GPA (it has happened overseas). It is crucial that target-site resistance to neonicotinoids does not develop as it would give GPA cross-resistance to sulfoxaflor (Transform®). If anything, the detection of metabolic resistance serves as a timely wakeup call to exercise the GPA Resistance Management Strategy.
We urge growers and agronomist to monitor for GPA in canola volunteers, forage crops and seedlings as we approach this winter-cropping season. Please help us in our quest to monitor and test for insecticide resistance in GPA by sending in samples following these instructions.
For more information contact:
Dr Siobhan de Little
Phone: (03) 9349 4723