Effects of temperature on the viability and infectivity of preparasitic larvae of Romanomermis yuanenesis
Peng, Y.; Song, J.; Platzer, E.G.
Hua Xi Yi Ke da Xue Xue Bao 27(1): 1-4
1996
ISSN/ISBN: 0257-7712 PMID: 9208610 Document Number: 463540
Romanomermis yuanenesis (Mermithidae: Nematoda) was found in Henan, China (Song and Peng, 1987), which has a broad host range in Culicinae mosquito and has been used successfully in field test for control of Culex tritaeniorhynchus, Culex fatigans and Aedes albopictus in Sichuan, Yunnan, Guangxi and Henan Provinces. This study was attempted to determine the viability and infectivity of preparasitic larvae in various temperatures. The cultures containing R. yuanenesis eggs were flooded 2h with distilled water, filtered and blocked with 1% agarose. Put the filter paper into water, then the motile preparasites separated from the unhatched eggs and got through the agarose membrane into water. About 200 ml water containing preparasites free from eggs were held at 26 degree C - 28 degree C , 16 degree C - 18 degree C and - 2 degree C - 2 degree C for test. The motility or lack of motility was used as the criterion to distinguish the living and dead nematodes. The rate of infection of mosquitoes and the rate of parasitism of nematodes were used to show the infectivity of the preserved preparasites. The results showed that at -2 degree C -2 degree C, more than 90% of preparasitic larvae of R. yuanenesis survived for 8 days and the rate of mosquito infection was 87.5% to 100%, but at 26 degree C -28 degree C and 16 degree C -18 degree C the survival times of 90% preparasites were only 24 hours and 48 hours respectively. It indicates the low temperature preservation may prolong the survival time and keep the infectivity of these preparasitic larvae.