Mediterranean fruit fly warning for fruit growers

FRUIT growers are urged to continue strict orchard hygiene and late foliage baiting over winter to reduce the impact of Mediterranean fruit fly (Medfly) on next season’s crop.

Department of Agriculture and Food (DAFWA) senior research officer Sonya Broughton said control work over winter and spring would be critical in reducing the carry-over populations of fruit fly.

“Research conducted by DAFWA has shown that Medfly populations start to increase from October,” Dr Broughton said.

“This is due to new flies emerging from overwintering sources such as pupae in the ground, and eggs laid in citrus and pome fruits in autumn and winter.”

A significant source is older flies that have ‘overwintered’ and become active at this time.

“By knocking down the overwintering population and ensuring that overwintering hosts are baited or eliminated, growers will have less of a problem in spring,” Dr Broughton said.“Growers should remember to bait all citrus trees, including lemons, as Medfly shelter and can breed over winter in mandarins, oranges and some lemons.”

Medfly can survive during the winter as larvae in apples, fruits that do not readily break down.

Dr Broughton said to apply baits in winter during fine, warm periods.

If it rains within six hours of application, then reapply during the next fine period.DAFWA reminds commercial growers that the APVMA permit allowing the use of fenthion ends on October 31.