Ultra-Low-Volume Applications of Synergized Pyrethrins for Stored-Product Insect Control1

Insect Management with Aerosols in Food-Processing Facilities

“…Some researchers used resin pellets impregnated with an insecticide, mainly dichlorvos, for releasing insecticide in vapor form either by a dispenser for providing large quantities of vapor Harein 1964, Harein et al 1971) or by placing pellets in a wire mesh tray to release the vapor into a confined space of a facility . In some studies, researchers have used portable devices or equipment to release the insecticide aerosols into the facilities such as a DeVilbiss sprayer equipped with an air-atomizing nozzle (Jay et al 1964), a 'Tifa'generating thermal aerosol machine (Childs 1967), a Dyna-Fog 70 thermal aerosol machine, a 6-nozzle McGill Fog-Trol pneumatic aerosol machine, a rotary-whip ULV applicator (Cogburn and Simonaitis 1975), a Micro-Gen S1W-5E unit dispenser (Bernhard and Bennett 1981), and a hand-held ULV applicator (Jenson et al 2010b). Some of the devices mentioned above such as rotary-whip ULV applicator or vapor dispenser have a built-in fan or blower for dispersing the aerosol particles more efficiently within a facility , Cogburn and Simonaitis 1975.…”

“…Although use of a non-synergized insecticide such as dichlorvos was very common when aerosol technology was introduced, pyrethrins and pyrethroids, used as aerosols later, contained a synergist, piperonyl butoxide, for improving the efficacy of aerosols against stored-product insects (Bernhard and Bennett 1981, Arthur 1988, 1993, Arthur and Gillenwater 1990). The latest strategy in aerosol technology is to use a combination of insecticides.…”

“…In a laboratory study, Bernhard and Bennett (1981) showed that the harborage level and exposure time to aerosol play a role in degree of insect control achieved in facilities. Simulating various levels of insect harborage by completely opening to completely closing the cabinet doors containing insects in an airtight chamber, they showed that adults of the rice weevil, Sitophilus oryzae (L.), were more susceptible than adults of T. confusum to a synergized pyrethrin applied as an ULV with particle sizes ranging from 5.7-28.6 µm.…”

“…Similarly, the adult mortality increased with increase in exposure time from 15 to 120 minutes. Bernhard and Bennett (1981) concluded that aerosols applied at ULV with 5.7-28.6 µm particle size ranges would be most effective only during application and the first 15 minutes after application, because larger droplets carrying the most of active ingredient settle down in the initial 15 minutes and the effectiveness of treatment decreases drastically thereafter. The above conclusion was supported by less than 10% mortality of adults of T. confusum and S. oryzae obtained when they were introduced in the treatment room 15 or 60 minutes after the application of synergized pyrethrins (Bernhard and Bennett 1981).…”