Insecticide resistance in green peach aphids

The extent of insecticide resistance in populations of the green peach aphid (Myzus persicae) has increased in Australia. The green peach aphid is a pest of canola and some pulse crops, and also attacks several horticultural commodities. Recent research has found that widespread resistance to synthetic pyrethroids and organophosphates exists right across Australia. The research, which is led by cesar, also showed that a number of field populations of green peach aphid have developed resistance to carbamates, including pirimicarb.

Resistance to pirimicarb was detected for the first time in Western Australia in 2010, and there continue to be chemical control issues experienced by WA farmers. Pirimicarb resistance has now been identified in populations from Victoria, New South Wales, South Australia and Queensland. This widespread resistance is concerning for pulse and oilseed growers because pirimicarb has been seen as a fallback for aphid populations resistant to other chemical classes. Pirimicarb is aphid-specific and less harmful to other invertebrates when applied to crops so is compatible with an integrated pest management approach.

In recent years, the increased usage and reliance on insecticides has accelerated the selection pressure placed on pest populations. To reduce the risk of problems developing in the future, the use of ‘insurance sprays’ should be avoided. Only apply insecticides after careful monitoring and correct identification of pest species. Although green peach aphids can spread important plant viruses, direct feeding damage requires large populations before economic losses are encountered. 

Growers are encouraged to keep an eye out for any control difficulties that arise when applying chemicals as per label instructions. It is important to rotate insecticide classes to help prevent resistance from developing further. If you experience any control failures involving crop aphids, contact Dr Annette Anderson (cesar) on (03) 93494723 or via email at aanderson@cesaraustralia.com.

For further information about resistance in the green peach aphid, click here.

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