Evaluation of a new toxic house fly scatter bait

Authors: Hogsette, Jerome - Jerry

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/14/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Toxic scatter baits have been a popular tool for house fly control for many years. In fact, Starbar’s Golden Malrin has been sold since 1966. Because of long-term use, resistance to methomyl, the active ingredient in Golden Malrin, has rendered the bait useless in many parts of the US. Increased resistance to Bayer’s Maxforce scatter bait, which has been reported in recent years, also reduces the effectiveness of this bait. Resistance to Starbar’s QuikStrike scatter bait (AI: dinotefuran 0.5%) has not yet been reported. Two new toxic scatter baits have appeared on the market in the past 12 months. One, Agita 10 WG (Novartis), contains thiamethoxam, the first commercially available 2nd-generation neonicotinoid belonging to the thianicotinyl sub-class. This yellow bait can be mixed with water and painted on. The other, Zyrox Granular Fly Bait (Syngenta), contains cyantraniliprole, from the chemical class of anthranilic diamides. Zyrox granules are amber in color. The main objective of the study was to evaluate Zyrox scatter bait against QuikStrike scatter bait in field tests. QuikStrike was chosen as the ‘control’ bait because it has no record of resistance. Zyrox bait was evaluated in the laboratory for knockdown. Zyrox has been shown to be a slow-acting bait and we wanted to verify that under our conditions. Zyrox bait (20 ml) in 7.6-cm dia. aluminum weigh boats was exposed to 50 adult house flies (3 to 5 days old) in standard colony cages (41 x 41 x 46 cm long). Bait was removed from the cage after 1 hr. Flies were observed more-or-less constantly during the first hr to determine the onset of toxic effects as characterized by tremors or reluctance or inability to fly. Mortality was recorded at 1, 2, 4, and 24 hr post exposure. Test was replicated 4 times. In the field, Zyrox was evaluated against QuikStrike scatter bait in paired tests near feeding areas on a dairy. Baits (30 ml) were exposed individually in light cardboard containers (15 x 15 with 2-cm lip pizza boxes or 18-cm diameter paper plates) which were placed in pairs at least 30 m apart in calf feeding areas. The same container type was used for each rep. Fly activity was observed for up to 1 hr and observations about fly attractions and mortality were recorded. Mortality counts and observations were made after 24 hr in the field. Number of paired baits was 4 and the test was repeated three times. In the laboratory study, most of the mortality was observed between 1 and 2 hr post exposure. House flies were not starved before exposure to the Zyrox bait. Sometimes they were immediately attracted to the bait and at other times attraction was much slower and they tended to rest on the sides of the cage. Signs of mortality began to appear almost 1 hr post exposure, mostly in the form of tremors. Some flies walked around the cage with an uneven gait for almost an hour but were reluctant or unable to fly. When flies decided to feed on Zyrox bait, they stayed in one place. On some baits, flies tend to feed and then move and feed again. Most dead flies were on the cage floor outside of the aluminum weigh boat. There was no recovery after 24 hr. In the field, baits were placed near sweet feed where many house flies and other flies were present. The weather was hot and dry and flies were clustered around moist, shady areas. When baits were placed at the selected sites, flies did not seem interested in either bait. Flies began to approach the baits in small numbers approximately 30 to 40 minutes after placement. Nearly 1 hour post exposure, some of the flies which had fed on the Zyrox bait were observed walking near the bait, but they were reluctant to fly. Some would fly, but they tended to flutter right back to the bait. This behavior mimicked laboratory observations, and we presumed that these flies would be dead within the hour. Mortality was faster with the QuikStrike ba