Date of this Version
PA-14, the compound presently registered for lethal control of blackbirds and starlings at roosts, is labelled for use only at upland sites. Research was undertaken to identify another wetting agent which might be registered for use at aquatic sites. Of 90 samples received from suppliers, 60 were evaluated for wetting ability in a standard laboratory test. Of these, 10 were chosen for test against an aquatic indicator animal, Daphnia. One of the 10, DRC-6749, a block copolymer, was found significantly low in toxicity, and underwent further aquatic testing against 6 fish and 1 mussel species. Under standard test conditions, no fish mortality occurred at concentrations up to 2,000 mg/1. Some fish mortality occurred at higher temperatures: for rainbow trout at 17 C and bluegills at 22°C were 801 and 740 mg/1 respectively. No mussel mortality occurred at these temperatures with concentrations up to 2,000 mg/1. Laboratory spray tests showed that DRC-6749 solutions were capable of wetting birds at reasonable application rates, and a field trial confirmed this with an estimated kill of 63,200 blackbirds and starlings from an application of 208 1 of DRC-6749 and 2.3 cm of water over a 0.46 ha area.