| Seetpotato weevil, Cylas formicarius(Fabricius), is a kind of international quarantine pests, major hazarding Ipomoea batatas(L.) Lam, Ipomoea aquatic etal. convolvulaceae plant. This article mainly studys the damage characteristics of the sweet potato weevil to different varieties of sweet potato and different sex ratio on the influence of population change. The main research results are as follows:(1)The experiment measured the length of tentacles of male and female Cylas for micarius raised under a certain temperature and humidity and photoperiod conditions,which is 1.33 ± 0.03 and 1.65 ± 0.04 mm.The result shows that mmin addition th e male antennae is longer than that of the female overall, which can be a criterion a s a preliminary judging male or female Cylas formicarius. In the meanwhile, the leng th of insect body length of male and female Cylas formicarius, with the result of 6.36±0.04 mm and 6.16±0.07mm; the length and width of egg of male and female Cyla s formicarius are 0.68±0.07 mm,0.46±0.04 mm, and comparing these data with foreig n species,there is no big difference.(2)For the study of the selective action to different varieties of sweet potato(19)by the seetpotato weevil, we test it using factometer, namely testing the reaction of s weet potato weevil in the sense of volatile odor given out by the surface of the diff erences between the sweet potato species.Comparie the test results with the second test of varieties of the bug number using correlation analysis, found that there is n o correlation between them.(3)Inoculate the same number of seetpotato weevil on the sweet potato varieties a nd investigate the offspring weevil number, and then calculate the corresponding resi stance differences between varieties of sweet potato to sweetpotato weevil. Also anal yzes the number of the offspring imale or female weevil, male and female ratio. The damaged area rate of different varieties was significantly positively related with its t otal number of the weevils,with R = 0.6489;Meanwhile, make the the correlation a nalysis between corresponding sweet potato varieties of total number of the weevils a nd some quality of sweet potato varieties,finding the resistance level of varieties to t he weevil has no obvious correlation with reducing sugar content, while the total sug ar, crude starch and the dry matter rate has a significant negative correlation with t he resistance level of varieties.(4)We studied the difference comparison on the different total number of weevil s, the average quantity of production of single female weewil,the number of male a nd female offspring, the male and female ratio in the feeding and hatching processadult mortality,under six different sex ratio treats(female/male is 19:1, 18:2, 16:4, 14:6, 12:8and 10:10). When a higher percentage of male and female occurs, it will red uce the average quantity of production of single female weewil and the quantity of p roduction of per female per day to some degree, which means we can increase th e female male sex ratio through sex attractant traps to decrease the number of sweet potato weevill. In the field interval days using sex attractant traps in the male had b etter not more than 34 days(under the condition of the corresponding growth perio d of sweetpotato weevil). |
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