สถาบันวิจัยวิทยาศาสตร์สาธารณสุข

National Institute of Health of Thailand

Distribution of Biting Midges Leptoconops spinosifrons (Carter) (Diptera: Ceratopogonidae) in Thailand and Field Efficacy of Herbal Repellent against L. spinosifrons

Authors : Usavadee THAVARA*, Apiwat TAWATSIN*, Jakkrawarn CHOMPOOSRI*,Somchai SAENGKITPORN*, Preecha ASAVADACHANUKORN**, Padet SIRIYASATIEN***,Arunrat THEPPARAT****, Mir S. MULLA*****
Affiliations:   
 

*National Institute of Health, Department of Medical Sciences, Ministry of Public Health,
  Nonthaburi 11000, Thailand
**Department of Statistics, Faculty of Commerce and Accountancy, Chulalongkorn University,
  Bangkok 10330, Thailand
***Department of Parasitology, Faculty of Medicine, Chulalongkorn University,
  Bangkok 10330, Thailand
****Department of Agricultural Technology, Faculty of Science, Ramkhamhaeng University,
  Bangkok 10240, Thailand
*****Department of Entomology, University of California, Riverside, CA 92521, USA

Source:   XXIV International Congress of Entomology August 19-25,2012 Daegu, Korea

 
Language:  
English

 
Abstract:
 

        Biting midges Leptoconops spinosifrons (Carter) are annoying pests found on the shorelines and sandy beach areas. In Thailand, L. spinosifrons has been found on various beaches in 9 provinces (Trat, Chantaburi, Rayong, Chonburi, Prachuab Kirikhan, Chumporn, Surat Thani, Nakhon Si Thammarat, Songkhla) around the Gulf of Thailand and 6 provinces (Ranong, Phang Nga, Krabi, Trang, Satun, Phuket) along the Andaman Sea, including some islands located in both seas. The biting midge has two peaks of biting activities (0700 to 0900 hours and 1600 to 1800 hours). It feeds on tourists and resident visiting the beaches and resorts. These insects deter human recreation and diminish Thailand tourism. Since the control of biting midges along beaches by larvicides or adulticides is hardly possible, attempts have been made then to prevent its nuisance by using repellent application. An herbal repellent, containing essential oils from Eucalyptus citriodora Hook. and Litsea cubeba (Lour.) Pers., was evaluated for repellency against L. spinosifrons in comparison with N,N-diethyl-3-methylbenzamide (deet). Both repellents were prepared as 20% in ethanol and each one was applied on the clothes (long sleeve T-shirt and pants) at the dosage of 0.5 mg a.i./cm2. Assessments were made using landing rates on the treated clothes as compared with controls (untreated clothes). Both repellents showed relatively high repellency against L. spinosifrons; however, the herbal repellent provided higher degree of repellency (98.3 – 99.7%) than did deet (82.7 – 98.5%). This study demonstrates a high potential for use of the herbal repellent to protect from biting of L. spinosifrons.

Key words: Biting midge, Leptoconops, Thailand, Repellent