European experience can provide no silver bullet for Western Australian commercial orchards and home gardens in controlling Mediterranean fruit fly.
This is the conclusion of Department of Agriculture and Food specialists following the recent visit of international expert Nikos Papadopoulos.
Fruit fly researcher Sonya Broughton said Dr Papadopoulos had confirmed the department’s belief that area-wide management was the best strategy for Medfly control.
“European orchardists lost access to the organo-phosphate chemical fenthion two years ago,” she said. “Like us they are learning more strategic management to protect valuable fruit crops.”
Dr Broughton said that removal of fruit in which fly maggots could survive over winter appeared to be an important factor in preventing population explosions in spring.
“In northern Greece, research has shown that maggots survive freezing temperatures for four to five months in apples lying on the ground or hanging in trees,” she said.
“We had thought flies were mainly overwintering here as pupae in the ground, but if they are surviving as larvae in fruit, it makes orchard hygiene a top priority.”
Dr Papadopoulos reviewed the department’s area-wide management program for fruit fly and has recommended some changes. This will include increasing the number of female traps in orchards, as female flies are usually detected before the males.
“Overseas research has also demonstrated considerable variation in fly populations within orchards,” Dr Broughton said. “Fruit left on a single tree can create a hot-spot of fly activity as weather warms up and they begin to breed again.”
Area-wide management of fruit fly combines four main tools – spray baiting, orchard hygiene, cover spraying and mass trapping. When flies are active, baiting is the grower’s most important weapon.
“Baiting early in the spring before you believe Medfly is active, combined with removing and destroying last season’s fruit is our best advice at this stage,” Dr Broughton added.
Media contact: Jodie Thomson, media liaison +61 (0)8 9368 3937