THE CONTROL OF APPLE MAGGOTS IN ORGANIC ORCHARDS WITH GF-120 NF NATURALYTE* FRUIT FLY BAIT

Abstract

The apple maggot (Rhagoletis pomonella) is indigenous to North America and is especially widespread in eastern Canada, causing fruit damage and economic loss. It is a quarantine pest and infested apples have little or no market value. For organic orchards, the only registered control product is Surround ® , a kaolin clay powder, serving to deter but not actively killing the maggot flies. GF-120 Naturalyte * fruit fly bait is a relatively new organic insecticide (0.02% spinosad) which has the potential to control apple maggot. Six field trials using different rates of GF-120 (1.5 L ha -1 , 2.25 L ha -1 and 3.0 L ha -1 ) were conducted in the summer of 2007 in organic orchards located in two Canadian provinces, Nova Scotia and Ontario; the efficacy of GF-120 was assessed by comgaring its performance to the level of apple maggot control achieved by Surround ® . Apple maggot pest pressure varied among the orchards under investigation. In Nova Scotia, the Block 84 orchard was heavily infested with apple maggot and among the unsprayed apples, 69% sustained some degree of fruit damage. In Ontario, 44% of the unsprayed apples in Home orchard had apple maggot damage. Unsprayed apples from the rest of the orchards had apple maggot injury ranging from 11-18%. Results showed that less than 3% of treated apples sustained apple maggot damage in any of the trials in this study except for those in Block 84 and Home. GF-120 tested at any rate was as effective as Surround ® in the control of apple maggot, with the exception of the Home orchard, where the lowest rate of GF-120 had significantly more infested apples than Surround ® . However in the Block 84 orchard, GF-120 at the lowest rate was as effective as Surround and was able to reduce fruit damage from 69% to 11%.