Methiocarb as a bird repellent on wine grapes

An experimental bird repellent, rnethiocarb, was evaluated as a spray treatment for reducing damage to ripening grapes at Loxton, South Australia, by blackbirds (Turdus merula) and grey breasted silvereyes (Zosterops lateralis). Methiocarb was applied to three border rows in an effort to protect the entire vineyard from bird damage. Yields and the incidence of bird damage on treated and untreated sides of a vineyard were compared. One application of rnethiocarb at the rate of 1.9 kg a.i. ha-1 four weeks before harvest protected the entire side of the vineyard from damage. Grapes on the treated side of the vineyard were either undamaged, or showed minor pecking; most bunches of grapes in untreated border rows were damaged. Yields from treated border rows were about double those from untreated border rows. Methiocarb residues of 1.3 ppm were recovered from Gordo grapes 28 days after harvest. There was no evidence that methiocarb killed any birds. Before border row treatment with methiocarb can be commercially recommended, more extensive observations need to be made to determine whether birds learn to fly over the treated rows. Also, the effects of methiocarb on fermentation need to be studied.