The use of an ant barrier on the trunk of custard apple trees as a means of reducing the need for insecticidal sprays for scale control is being demonstrated in a number of orchards this winter.
Ants tender and protect scale insects on trees, making control more difficult. However, once the ants are excluded from the tree, parasitic and predacious insects can attack the scale.
The material being used is a sticky polybutene (Tac Gel R) which has been dissolved by a solvent, making it easy to apply with a small paint brush onto a plastic film collar placed around the tree. The sticky polybutene is painted onto the collar and the solvent evaporates leaving an impenetrable layer over which the ants cannot travel.
The material works for as long as there are no branches in contact with the ground and no bridge is constructed over the sticky barrier.
The ideal time to apply the sticky barrier is at the start of the season in November/December when the tree is coming into leaf.
The research was done at the Tropical Fruit Research Station, Alstonville.
DATE: January 1992
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