Résumé
<p><b>OBJECTIVE</b>To find out an appraisal method of temperature on the first appearance date of Culex tritaeniorhynchus in spring.</p><p><b>METHODS</b>Whole night collection of mosquitoes mosquitoes (from 18:00 hours to 06:00 hours of the following day) with light traps had been carried out in pig sties every night since 1 March in 1982 - 1992 and 2001 - 2002 in Fengxian area Shanghai. The adult mosquitoes caught were anaesthetized, then identified and counted. The density of mosquitoes was calculated by the average number of mosquitos per one trap and one night. Comparative analysis of the mean daily air temperature at 7 days before, the first appearance date and 1 day after, the first appearance date of Culex tritaeniorhynchus.</p><p><b>RESULTS</b>Data of the first appearance data of Culex tritaeniorhynchus were judged to mean daily air temperature and cumulative temperature on the day of the first appearance of Culex tritaeniorhynchus and the day before appearance, or 3 days on the day of the first appearance of Culex tritaeniorhynchus and the two days before appearance and the day since appearance with a difference less than 1 - 2 day (91.7%).</p><p><b>CONCLUSION</b>The first appearance of Culex tritaeniorhynchus in spring accompanied with a course of influence by the severe warm air advection from south of China, and lowest mean daily air temperature of the first appearance was 11 degrees. Thus the first appearance data of Culex tritaeniorhynchus could be deduced and rehabilitated from observed values of mean daily air temperature or its forecasting values.</p>