Health Canada’s Pest Management Regulatory Agency (PMRA) conducted a re-evaluation of diazinon uses in Canada and determined that most uses could no longer be supported due to health and environmental risk concerns. Through consultation with stakeholders, critical uses of diazinon that had no alternative control strategies were identified for longer-term phase-out to provide more time to develop a risk management plan. In June 2013, PMRA communicated the phase-out dates for diazinon products and the mitigation measures required to further protect workers and the environment, which can be found in their consultation document titled REV2013-01, Diazinon Risk Management Plan.
How will this phase-out affect Canadian apple growers?
In apples, the last date of use for both registered diazinon products, Diazinon 50 WSP (PCP #29976) and Diazinon 500 E (PCP #11889) is December 31, 2016.
Alternative options for diazinon are available for most apple pests. However, alternative products may be limited based on the number of different chemical groups to rotate between for resistance management and/or certain alternatives may not provide as effective or consistent control as diazinon for some insect pests (e.g., mullein bug, wooly apple aphid).
With relatively few alternative options for some pests, it is important to take the following steps to avoid development of insecticide resistance:
• For pests with discrete generations (ie., mullein bug, apple maggot, scale, leafcurling midge), do not use insecticides from the same group for more than one generation. Within a generation, if more than one spray is required, use a product from the same chemical group.
• For pests with rapidly building and overlapping generations (ie. aphids), do not use products containing the same chemical group in consecutive applications.
For a chart on alternatives for some pests commonly controlled by diazinon, see http://ow.ly/ZGlcN
Source: OMAFRA Orchard Network newsletter
Photo by Glenn Lowson