Biological Control of Culex pipiens pallens (Diptera, Culicidae) bythe Release of Fish Muddy Loach, Misgurnus mizolepisin Natural Ponds, Korea

Biological Control of Culex pipiens pallens (Diptera, Culicidae) bythe Release of Fish Muddy Loach, Misgurnus mizolepisin Natural Ponds, Korea

An assessment on the biological control potential with the f ish muddy loaches (Misgurnus mizolepis) was conducted against naturally bred Culex pipiens pallens larvae in four ponds (A, B, C and D) in Busan from July through September, 2001. Predation of the f ish at 3 different release rates of 4, 5, and 6 fish/m2 resulted in mostly over 90% mosquito control from the .rst week after treatment through the end of the survey period for 11 weeks. There were no significant difference among the release rates of fish at the 5% level of probability. However, substantial controls of 43.0% and 25.9% were obtained from pond C during the 3rd and 7th weeks after the f ish introduction, respectively. The results of those two weeks showed a lower biological control by the introduced larvivorous f ishes.This might be due to the presence of heavy organic matters including aquatic weeds and/or severely polluted water from sewage in pond C. The aquatic weeds covered the pond’s water surface which may have affected the deterioration of mosquito preying in favor of aquatic weeds. Also, the .shes were observed to avoid severely contaminated sewage water in some parts of ponds A and C where more mosquito larvae were found.

An assessment on the biological control potential with the f ish muddy loaches (Misgurnus mizolepis) was conducted against naturally bred Culex pipiens pallens larvae in four ponds (A, B, C and D) in Busan from July through September, 2001. Predation of the f ish at 3 different release rates of 4, 5, and 6 fish/m2 resulted in mostly over 90% mosquito control from the .rst week after treatment through the end of the survey period for 11 weeks. There were no significant difference among the release rates of fish at the 5% level of probability. However, substantial controls of 43.0% and 25.9% were obtained from pond C during the 3rd and 7th weeks after the f ish introduction, respectively. The results of those two weeks showed a lower biological control by the introduced larvivorous f ishes.This might be due to the presence of heavy organic matters including aquatic weeds and/or severely polluted water from sewage in pond C. The aquatic weeds covered the pond’s water surface which may have affected the deterioration of mosquito preying in favor of aquatic weeds. Also, the .shes were observed to avoid severely contaminated sewage water in some parts of ponds A and C where more mosquito larvae were found.