Fruit fly on the go

Queensland Fruit Fly (QFF) will soon wake after their winter down-time as the weather becomes warm enough for them to fl y and mate. These adult flies will look for carbohydrates to increase their energy and protein for sexual maturity. Having used their reserves to survive winter, they need to re-energise. Flower nectar provides an ideal carbohydrate source, while protein can be found in yeasts, fungi and bacteria growing on branches.

Pre-spring garden hygiene

Home gardeners should be on the look-out for black marks and soft spots on early ripening fruit that may indicate fruit fl y stings. Suspect fruit can be cut open and held to the light to inspect for eggs and young larvae glistening in fruit pulp. Loquats are the main culprits to look-out for in August.

Stung loquats or late-hanging autumn fruits (pomegranates, quinces, apples, oranges) should be fed to the chooks, solarised in a plastic bag or buried deep below the soil.

Fruit fly resistant options

There are some fruit and fruiting vegetables that are more resistant to QFF than others. Planting out seedlings or grafted tomato plants now in a warm spot or greenhouse for fruit before Christmas is a good idea, as fruit flies are prevalent in January and February. Cherry and Roma tomatoes are a little more resistant to fruit fl y attack than larger, softer, more wrinkled tomato varieties.

Fruit and vegetables resistant to QFF include eggplants, cucumbers, zucchini, pumpkins, Finger limes, Tahitian limes, Eureka lemons, Lisbon lemons, chokos and monstera. Mandarins, grapefruit, lemonades and Meyer lemons are not resistant.

Fruit fly survival strategies

An adult fruit fly is highly mobile across the landscape with flight distances and durations becoming progressively shorter as the weather cools in autumn to winter and then lengthening again as the weather warms up after August/September.

In cooler months adults are no longer looking for partners to mate with or fruit to lay their eggs into. Over winter they are focused on surviving the cold by searching for protein, sugar, water and above all, shelter from predators, cold weather and wind. As the weather warms up flies revert to their reproductive mode of seeking protein, mates, fruit to lay eggs into and shelter from predators, the heat and wind.