01 September 2020

The importance of IPM practices in citrus

The importance of IPM practices in citrus  

1 September 2020

Over the last 25 years, citrus growers have focused on producing clean fruit to maintain high pack-outs in high-value export markets that often have a zero tolerance for pests.

In the last decade, several effective new chemistries have been released for key pests. However, the imperative to produce clean fruit has made citrus producers very dependent on these products. Overuse, or very regular seasonal use, can have repercussions:

  • Outbreaks of pests that are not normally pests of citrus can occur — for example two spotted mite, cottony cushion scale or rust mite. If beneficial insects or mites are removed or suppressed by spray treatments, they cannot regulate the pest population.
  • Pesticide resistance can develop, rendering products useless. Chemicals must be used responsibly to maintain their viable lifespans for as long as possible.
  • Residues may exceed the maximum residue limits (MRLs) in export or domestic markets.

To conserve the valuable and effective chemicals currently in use, it is critical to revisit Integrated Pest Management (IPM) strategies.

IPM has had a long history in citrus production in Australia. Between 1970 and 1990 many exotic beneficial insects (mostly wasp species) were introduced into citrus orchards to control armoured scales, mealybugs, and citrus leaf miner. Native beneficials that control spined citrus bug and citrus gall wasp have also been relocated into regions where they did not naturally exist.

Beneficial species remain the cornerstone of pest control in most orchards in most districts, and need to be respected and preserved for the future.

If host-specific beneficial species are eliminated from orchards, and chemicals are either withdrawn or become ineffective – what are the options? We need to be producing high quality citrus for decades to come – not just this year and next.

It may be time to rethink our tolerance of low levels of pests, and manage the activity of beneficials in conjunction with managing pests.

An accredited entomology consultant can recommend management processes that support beneficials. For example, rotating between different chemistry types and creating untreated refuge areas within an orchard.

You can read about ‘red scale suppression with Aphytis melinus wasps’ here.

James Altmann is Owner/Director of Biological Services in Loxton, SA.

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