关键词: 稻纵卷叶螟, 生理状态, 性信息素, 花香气味, 诱捕, 种群监测

Abstract: 【Aim】 To clarify the impact of the physiological state of the rice leaffolder, Cnaphalocrocis medinalis on its responses to sex pheromone and floral odor in olfactory behavior, and the dynamics of moth catches by sex pheromone and floral trapping in the field. 【Methods】 The moths of rice leaffolders were caught using net catching, and floral and sex pheromone trapping in the field in five test sites in Guangxi, Hunan, Zhejiang, and Sichuan in 2020. The differences in the olfactory behavior of moths caught by sex pheromone and floral trapping among the immigratory type (strong migratory type), local breeding type (residence and dispersal types), and emigratory type (strong migratory type) were compared by dissecting the ovaries and testes of moths. The number of larvae at each instar and their dynamics were investigated in the field according to the surveillance standards. The relationship between the dynamics of moths caught by sex pheromone and floral trapping and the population and occurrence time of larvae at each instar in the field was investigated, and the changes in the percentage of mature ovaries of female moths sampled by net catching and floral trapping with the physiological state of moths and season were analyzed as well.【Results】 The rice leaffolders of immigratory type may have mated during the migration, and entered a behavioral quiescent period after landing, causing them to first respond to sex pheromone, and then to floral ordor at the late stage of oviposition. The time difference between the moth peaks of sex pheromone and floral trapping was close to the pre-oviposition time. The moths of local breeding type showed a strong response to sex pheromone and sex pheromone trapping was very effective, but not to floral lure. The numbers of emigratory type  male moths caught by sex pheromone trapping and female and male moths caught by floral trapping were very low. The ovarian level of immigratory type female moths trapped by floral lures was relatively high, especially the percentage of oviposited female moths with level Ⅴ ovaries caught by floral trapping was much higher than that by net catching. For local breeding populations, the number of matings in female moths trapped by floral lure was significantly higher than that in female moths trapped by net catching in the field. For example, in Youxian, Hunan, the number of matings of female moths with level Ⅴovaries by floral trapping was 3.5±1.0, with the maximum value of 5, while the number of matings in female moths with level Ⅴ ovaries caught by net catching was 2.6±0.4, with the maximum value of 3. The male moths trapped by net catching had the largest testis volume, followed by those trapped by sex pheromone lure, and those caught by floral trapping had the smallest testis volume. The mortality rate of male moths by sex pheromone trapping was significantly lower than that of male moths caught by floral trapping. Floral trapping occurred throughout the night with the first peak appearing right after darkness, while sex pheromone trapping occurred from 1∶00 am until dawn. Analysis of trapping dynamics revealed the peak of moths of immigratory type trapped by sex heromone lure occurred earlier than that by floral lure. During the same period, by investigating the rice fields in Tianyang, Guangxi, and Youxian, Hunan, it was found that there was a correlation between the development and the number dynamics of larvae at each instar and the number of moth catches by sex pheromone trapping. 【Conclusion】 The correlation between the population and occurrence time of larvae at each instar and the number of C. medinalis moths caught by sex pheromone and floral trapping has been initially established in the rice fields, providing a technical basis for the precise application of pesticides in controlling the rice leafrollers in the field.

Key words: Cnaphalocrocis medinalis, physiological state, sex pheromone, floral odor, trapping, population monitoring