Protein bait sprays

Fruit Fly is a one of the most important economic threats to horticulture. If not managed properly, fruit fl y has the potential to wipe out an entire industry in a single season. It is the responsibility of all fruit and vegetable growers, both urban and rural, to manage their fruit and vegetables and reduce the spread of fruit fly. Most commercial fruit growers have regular management strategies in place to prevent the threat of fruit fl y outbreaks. Unfortunately, many home gardeners are unaware or ignorant of the role they have to play in the area wide management of fruit fl y. There are a number of effective management practices recommended for home gardeners, including:

  • Trapping and monitoring.
  • Pruning to a manageable height.
  • Picking ripened fruit.
  • Netting of fruit trees and vegetables with specialised fruit fl y netting.
  • Picking up fallen fruit and disposing of correctly.

What is a bait spray?

A bait spray is a mixture of a protein bait attractant (usually a yeast liquid), mixed with a small amount of a registered insecticide, e.g. Malathion. It is applied as a “spot spray” (only about a 50ml squirt), to the trunk or foliage of a tree or plant. There is no need to spray the whole tree.

Why is it so effective?

Female flies need to feed on protein before laying eggs. They are attracted to the protein and when ingested, the insecticide kills the fly before egg laying occurs.

When should a bait spray be applied?

  • Ideally, bait spraying of host plants should commence early in spring, when the weather starts to warm up. This is when overwintering fruit flies become active again and look for a mate to breed.
  • It is important to maintain a regular baiting program from the time you start, until autumn (or trees are dropping their leaves).
  • Bait sprays must be applied at 7-10 day intervals throughout the entire season.
  • Apply baits as high in the foliage or trunk as possible.
  • Re-apply bait immediately after rainfall of 20mm or more.

Things to remember when applying bait sprays

• Use only as directed. Failure to follow label instructions can damage fruit.
• Wear protective clothing when mixing and spraying.
• Avoid contact of bait spray with fruit or other edible plants.

Bait spray availability

Bait sprays are available through your local agricultural supplier, nurseries and hardware stores. Several products are available, including a natural bait spray mixture, which contains a bacterium.