The Department of Agriculture and Food is urging commercial fruit growers to begin baiting now for Mediterranean fruit fly (Medfly) so they can commence summer with the lowest possible fruit fly population.
Senior research officer Sonya Broughton said temperature was the main driver for Medfly activity and it was vital to keep numbers down before fruit ripened.
Dr Broughton said although vulnerable stone fruit and other fruit are just setting in orchards, fruit fly numbers are building up in citrus and shelter trees.
“Mediterranean fruit fly survives through the winter in our climate in the adult stage, as larva in fallen fruit or fruit left on trees, or pupa in the ground,” she said.
“When deciduous trees, such as stone and pome fruit are bare of leaves, Medfly will shelter in citrus and other evergreen trees, awaiting warmer weather. Medfly can also breed during winter, particularly in citrus.
“After mating, the female Medfly is desperate to lay her eggs and will lay in hard, green fruit if the population is large enough and few host plants are available.”
Growers are advised to begin foliage baiting citrus and evergreens in and around orchards as soon as possible to hit the fly while its numbers are low.
Backyard owners of lemon, loquat and early stone fruit trees should also begin baiting.
“Foliage baiting each week and installing lure and kill devices are the best weapons to complement restrictions on the use of traditional cover sprays,” Dr Broughton said.
“The female Medfly requires protein to mature her eggs and maintain egg production. When coarse droplets of protein laced with insecticide are applied to leaves, both male and female flies are attracted as they forage, acquiring a lethal dose of insecticide.”
Dr Broughton said although spot spraying was targeted and conserved beneficial insects, it could fail when highly susceptible and more attractive fruits, such as ripe stone fruit, are available.
“Lure and kill devices act in a similar way to spot sprays, but flies are killed by drowning or coming into contact with insecticide in the device,” she said.
“Effectiveness increases if baits or lure and kill devices are applied over a large area as part of an area-wide management program, or community baiting scheme.”
More details about Medfly control are available are on the department’s website at agric.wa.gov.au
Media contact: Jodie Thomson/Lisa Bertram, media liaison +61 (0)8 9368 3937