Responses of Glossina pallidipes Diptera: Glossinidae to synthetic repellents in the field.
In Zimbabwe, studies were made of the responses of Glossina pallidipes Austen to known and candidate repellents. Various chemicals, dispensed at c. 5–10 mg/h, were placed beside Epsilon traps already baited with a blend of acetone, octenol, 4-methylphenol and 3-n-propylphenol. Pentanoic or hexanoic acids or acetophenone halved the catch and 2-methoxyphenol reduced the catch by 90%. There were no consistent differences in the responses of males and females. Pentanoic acid or acetophenone or 2-methoxyphenol at an unbaited trap reduced the catch by 40%, 75% and 60%, respectively. Baiting traps with a combination of pentanoic acid, acetophenone and 2-methoxyphenol did not reduce the catch below that produced by 2-methoxyphenol alone. Pentanoic acid and 2-methoxyphenol reduced the efficiency of traps from c. 40% to 20% but acetophenone had no significant effect. Acetophenone and 2-methoxyphenol halved the numbers of tsetse attracted to a target baited with acetone, octenol and phenols but none had a significant effect on the proportion that landed. 2-Methoxyphenol significantly reduced the numbers of tsetse attracted to a source of natural ox odour but only pentanoic acid had a significant effect on feeding responses, reducing the proportion that fed on an ox from 59 to 45%. It is concluded that these repellents do not provide any useful degree of protection against trypanosomiasis. In areas where tsetse are abundant (500 bites/ox/day) and infection rates in tsetse are high (>5%) it is highly unlikely that any repellents would be useful. However, in areas where tsetse are less abundant (1 bite/ox/day) and/or infection rates are low (c. 0.5%) the potent, unidentified repellents present in human odour might effectively complement the control of disease using trypanocidal drugs.
Torr, S.J.; Hall, D.R.; Mangwiro, T.N.C. Responses of Glossina pallidipes Diptera: Glossinidae to synthetic repellents in the field. Bulletin of Entomological Research (1996) 86 (05) 609. [DOI: 10.1017/S0007485300039419]