| Sugarcane borers are widely distributed in the world. In Guangxi Province, the sugarcane borers were the main pests of sugarcane in the fields. In order to understand the species and population dynamics of sugarcane borers in the fieldsin Guangxi Province, the method of random sample was used to investigat thate in Wuming country, Nanning City, Guangxi Province. Furthermore, reproductive behavior of the main species of sugarcane, Chilo infuscatellus Snellen, was also studied. The main results are as follows:1. Total of five species of sugarcane borers were investigated, including Chilo infuscatellus Snellen, Chilo sacchariphagu Bojer, Tetramoeras chistaceana Snellen, Sesamia inferens Walker and Tryporyza intacta Snellen. Among these species, C. infuscatellus, C. sacchariphagus B and T. chistaceana S were the dominant species. Although these dominant species could be investigated throughout the growing season of sugarcane, the species and the population quantity were different during the difffrent growth stages.2. In the fields, C. sacchariphagus B and C. infuscatellus were mainly investigated in the seedling and tiller stages, while C. sacchariphagus B appeared in the periods of elongation and maturity of sugarcane. Population quantity of C. sacchariphagus B, C. infuscatellus, T. chistaceana S,S. inferens damaged in the seedling stage were accounted for 48.62±3.22%、32.70±1.26%.13.65±0.89% and 6.03±2.38%, respectively.Population quantity of C. sacchariphagus B,C. infuscatellus and T. chistaceana S damaged in the tiller stage were accounted for 83.22±9.32%、12.35±2.31% and 5.53±1.98%, respectively. However, in the periods of elongation and maturity, the population quantity of C. sacchariphagus B was accounted for 85.00% than that of C. infuscatellus which was accounted for 10.00%.3. Under room temperature, C. infuscatellus developed five generations in one year in Nanning City. Duration of each generation was 45 days, and the phenomenon of generations overlapping was observed. C. infuscatellus overwintered as part of older larvae of the 5th generation and part of 5-6 instar larvae of the 6th generation.4. The longevity of adults were related to the sex and supplementary nutrition. The average longevity of female adults respectively were 5.21±0.29 and 2.69±0.15, and has significant differences under the conditions of providing with supplementary nutrition and without it. The average longevity of male adults has the same trend as females. From the pespective of sex, the longevity of female adults were longer than the males no matter whether supplementary nutrition was provided.5. The emergence of C. infuscatellus occurred at night from 9:00 pm to 4:00 am, in which the peak of emergence was from 12:00 pm to 1:00 am accounted for 22.67%. The percentages of emergence from 11:00 pm to 12:00 pm and 1:00 am to 2:00 am accounts for 18.00% and 15.33%.6. The C. infuscatellus adults only mated once in their life. The mating activity usually occurred after two hours when the night time has began. The mating mainly appeared from 11:00 pm to 4:00 am that the mating percentage wasmore than 95.00%. The peak of matingbegan from 12:00 pm to 1:00 am and from 3:00 am to 4:00 am, of which the mating percentages were 27.33% and 32.00%. It is a bimodal pattern. The duration of mating was 40.60±19.36min. Most individual of mating duration was be from 20 minutes to 60 minutes, which accounted for 92%.7. There is an significant differences of egg production and hatchability between the mated females and unmated females. The average egg production was 143.1±22.6 for the mated female moths, and 76.1±32.6 for unmated females. The hatchability of mated females was 93.62%, The hatchability of unmated females was 0.0%. The spawning activity occurred from 10:00 pm to 5:00 am. The peak of spawning was be from 12:00 pm to 1:00 am that accounted for 53.90%. Results suggested that the spawning rhythm showed an unimodal distribution pattern.8. The developmental duration and survival of egg, larvae and pupae in C. infuscatellus was different under 19℃,23℃,27℃,31℃ and 35℃ with 80±5% relative humidity. The average developmental duration of eggs were 15.2±.1.1d,10.3±0.8d,5.5±0.2d 4.6±0.5d and 4.4±1.2d. The average developmental duration of larvae were 36.9±1.8d,32.6±2.3d,27.5±1.9 25.0±2.3d and 24.0±1.8d under 19℃,23℃,27℃ 31℃ and 35℃, respectively. The average developed duration of pupa were 17.7±1.2d,13.2±0.9d,8.3±0.6d 7.7±0.4d and 6.8±1.3d under 19℃,23℃,27℃ 31℃ and 35℃, respectively.9. The egg production and adult longevity of C. infuscatellus was studied under 19℃, 23℃,27℃ 31℃ and 35℃ with 80±5% relative humidity. The average of egg production were 32.3±10.6,83.6±30.5,142.5±22.6 130.0±45.6 and 115.2±53.1 under 19℃,23℃,27℃ 31 ℃ and 35℃, respectively. The adult longevity were 10.1±2.4d,8.7±0.9d,4.8±1.2d 3.2±1.7d and 2.7±1.3d under 19℃,23℃,27℃ 31℃ and 35℃, respectively. The number of eggs produced per female and adult longevity had no significant differences under 27℃ and 35℃. |
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