Fruit fly activity to look out for

August weather forecasts of higher than average temperatures are likely in the Goulburn Murray Valley and have the potential to lead to earlier fruit fly activity than usual.

The warmer weather will see adult flies begin to wake up from their winter down-time and become more active. Evergreen trees such as lemon and loquat trees are favoured winter refuges and require extra attention.

At this time of the year fruit flies are likely to have used most of their energy reserves to have survived the winter months. Fruit flies will be on the look out for carbohydrates from nectar and protein from yeasts, fungi and bacteria growing on branches.

Caution required

Once temperatures hit 16˚C or more at sunset, fruit fly have the ability to mate. If there are areas where temperatures are warmer at dusk flies will mate and then lay eggs into fruit one or two days later.

Look out for black marks and soft spots on early ripening fruit that might indicate fruit fly stings. If you cut suspect fruit open and hold it up to the light you may be able to see eggs and young larvae glistening in the fruit pulp.

Fruit requiring extra care

Loquats, apricots and winter citrus require extra attention at this time of the year. If you have stung loquats or late-hanging fruit such as like pomegranates, quinces and apples pull them off, or rake them up and feed them to the chooks or destroy them in plastic bags placed in the sun or by deep burial. Infested fruit must not be placed in the compost heap where its warmth and humidity provides one of the best spots for fruit fly to survive.

If you have lemons and had fruit flies last season try putting a male or female fruit fly trap or two nearby to check if these pests are starting to move.

Try planting out tomato seedlings or grafted plants now in a warm spot so you get fruit prior to Christmas before fruit fly populations become more active. Cherry and Roma tomatoes may be slightly more resistant to fruit fly attack than larger, softer tomato varieties.

Hot spot areas

Hot spot risk areas for August include:

  • Orrvale
  • Shepparton East
  • Shepparton Urban
  • Tatura Rural
  • Toolamba