Diximermis peterseni (Nematoda: Mermithidae): a potential biocontrol agent of Anopheles mosquito larvae

The mermithid nematode Diximermis peterseni was successfully transferred and established in an artificial pond and then in a natural pond. The exposure in the artificial pond initially produced 92% parasitism in introduced larvae of Anopheles quadrimaculatus; then parasite activity gradually decreased and disappeared. However, it reappeared 8 months after the introduction and has been observed in introduced hosts during each of the 40 months since. The release of 2300 Anopheles (85–90% infected) into a natural pond (January–March 1971) produced 12–100% parasitism during the 8-month period between September 1971, and March 1972. Furthermore, during the same months in 1972–1973, an average of 88% of the Anopheles in the pond were parasitized. These data indicate that D. peterseni can be easily established and will produce significant levels of parasitism despite long periods of dry weather and low host densities.