Field Evaluation of Repellents and Insecticidal Aerosol Compositions for Repelling and Control of Siphunculina funicola (Diptera: Chloropidae) on Aggregation Sites in Thailand

Abstract

The oriental eye fly Siphunculina funicola, a small member (1.5-1.6 mm) of the family Chloropidae, is extremely annoying to humans and domestic animals, feeding on mucous membranes, secretions, and other moist surfaces of their hosts. In central Thailand heavy populations were detected during 2006-2007 in some rural, agricultural, and periurban areas of the region. They were noted to exhibit strong synanthropy and aggregation behavior, congregating on thin (1-5 mm diam) substrates hanging in or near human habitations and animal shelters and other structures open on one or more sides. We initiated studies on the repelling and control of this eye fly at their aggregation sites, the most vulnerable targets near or in human habitations. Four formulations of repellents consisting of Everside, 3 fatty acids (with 8, 9, and 10 carbons), permethrin, and the acids C8910 plus permethrin in Everside were diluted 1:3 in tap water and sprayed on to the aggregation sites. Prior to treatment all sites including controls were disturbed to dislodge eye flies, and then the blank sites were sprayed with the aqueous suspension of the repellents. Additionally, we evaluated 3 commercially available household insecticidal aerosol formulations by treating eye flies and their resting sites (without dislodging the flies) with puffs of the aerosols. Two treatments with permethrin alone and permethrin plus acids in Nakhorn Ratchasima Province caused a complete absence of flies from the sites up to 23 h. After treatment with the repellents, the repelled flies and others were found to congregate on untreated favorable sites close to the treated ones. The repellents tested against eye flies in Chonburi Province at 2 locations caused almost complete absence of this insect on aggregation sites up to 120 h. Three household insecticide aerosols applied to aggregation sites with resting and hovering eye flies produced high to complete mortality and reduction of eye flies for 48 h or possibly longer in the treated sites. This is the first time that procedures for the evaluation of repellents and insecticides against eye flies have been tested and developed. The use of commonly available insecticide aerosol products could provide a good source of materials for the elimination of eye flies from their domestic and peridomestic aggregation sites.