CORN STEEPWATER AS PROTEIN BAIT FOR ANASTREPHA-SUSPENSA (DIPTERA, TEPHRITIDAE)

Field trials were conducted to determine the potential use of corn ste epwater, an acid-hydrolyzed com product, as a liquid bait for the Cari bbean fruit fly, Anastrepha suspensa (Loew), in Florida. Preference te sts compared relative attractiveness among aqueous solutions of standa rd torula yeast plus sodium borate pellets or 10% steepwater (vol:vol) plus 1, 3, 5, and 10% (wt:vol) borax in traps. Total number of female s trapped decreased from 474 in fresh bait solution to 197 and 154 in 2-3-d old and 4-6-d old bait solutions, respectively. When freshly pre pared solutions were tested, the torula yeast-borax solution was the m ost attractive and the 10% steepwater with 1% borax the second most at tractive bait formulation, capturing 45 and 23% of the trapped females , respectively. After 2-3 d of field-use, there was less discriminatio n among the baits, although the 10% steepwater with 1% borax and with 10% borax each captured 29% of the trapped flies. By the last 4-6 d of field use, the 10% steepwater with 1% borax was most preferred and ca ptured 45% of the trapped flies. Dissections of subsamples of trapped females indicated that only 50% of the females from tortula yeast-bora x traps were unmated, while 80-95% of the females caught in any of the steepwater traps were unmated. The addition of 1, 3, 5, and 10% borax increased the initial pH of the acidic steepwater to 5.95, 7.76, 8.44 , and 8.76, respectively. The relative attractiveness of the 10% steep water with 1% borax increased as this bait approached a neutral pH ove r the 6 d of field use.