Performances of the cotton bollworm,Heliothis armigera (Hubner) at different temperatures and relative humidities

The cotton bollworm, Heliothis armigera (Hubner) is an important insect species at-tacking many crops. Their performances have been examined at temperatures from 15℃ to 35℃ and relative humidities (RH) between 22.5% and 100%, respectively, in order to assess possible effect of climate in future on its occurrence and infestation. Durations of all developmental stages of the insect shortened with increasing temperature. The temperature favoring population growth ranged from 25℃ to 30℃.Larval duration and adult longevity decreased as relative humidity increased, but development of other stages was independent of RH. At RH of over 64%, their survival rate, egg production and oviposition rate varied a little, and all the population parameters of the insect remained at a relative constant level.     

综合防治棉铃虫的区域性技术体系研究

研究改进了棉铃虫中期预报方法；提出“一代监测、二代保顶、三代保蕾、四代保铃”为主的防治策略；研究制定适用于不同世代、不同水肥条件的科学防治指标，协调应用多种配套措施保护、利用自然天敌控害，系统监测和治理棉铃虫抗药性；利用棉花种质资源和品种的抗病、抗虫性；诱杀成虫；组建大面积综防技术体系。在１９９２～１９９５年棉铃虫猩獗发生的情况下，于河南省新乡县棉花病虫害综防示范区大面积实施后，有效控制了棉铃虫危害。     

棉铃虫灾害的长期性及性信息素的减灾控害作用

简要分析了我国棉铃虫灾害的长期性,并较全面地介绍了性信息素在减灾控害中的作用。这些作用可分为：帮助识别对象害虫、监测种群状态、迅速普及虫情信息、直接诱杀雄虫以及提前1周开展减灾行动等。直接诱杀雄虫后,引起雌雄比上升,雌蛾产卵量下降,孵化率降低,幼虫及为害量减少,其中幼虫量一般减少20％－50％。根据在新疆、山东等地的试用经验,作者在首次指出性信息帮助识别害虫和迅速普及虫情信息对减灾的关键作用,并讨论了性信息素的干扰交配和诱杀雌虫的可能作用,以及使用性信息素与农业可持续发展的关系。     

Performances of the cotton bollworm,Heliothis armigera (Hubner) at different temperatures and relative humidities

The cotton bollworm, Heliothis armigera (Hubner) is an important insect species at-tacking many crops. Their performances have been examined at temperatures from 15℃ to 35℃ and relative humidities (RH) between 22.5% and 100%, respectively, in order to assess possible effect of climate in future on its occurrence and infestation. Durations of all developmental stages of the insect shortened with increasing temperature. The temperature favoring population growth ranged from 25℃ to 30℃.Larval duration and adult longevity decreased as relative humidity increased, but development of other stages was independent of RH. At RH of over 64%, their survival rate, egg production and oviposition rate varied a little, and all the population parameters of the insect remained at a relative constant level.     

Effects of Cd2+ exposure on key life history traits and activities of four metabolic enzymes in Helicoverpa armigera (Lepidopteran: Noctuidae)

Cadmium (Cd) is a toxic non-essential element accumulated easily in living organisms due to its non-biodegradable nature. A slight increase in Cd levels will threaten the health of terrestrial and aquatic organisms. Therefore, Cd contamination and its effects on the ecosystems and organisms have become a major topic of eco-toxicological research. The present study investigated the eco-toxicological effects of Cd-supplemented diet on some life history traits and specific enzyme activities of carboxylesterase (CarE), glutathione S-transferase (GST), acetylcholinesterase (AChE) and cytochrome P450 monooxygenases (P450s) in the cotton bollworm, Helicoverpa armigera. The results showed that Cd significantly decreased larval survival, pupation and emergence, and reduced body mass of the sixth instar larvae, pupae, adult moths and female fecundity. Cd-supplemented diet also delayed the development of larvae and pupae and shortened the life span of the cotton bollworm moth. In addition, dietary Cd inhibited the activities of GST, CarE and P450, but increased AChE activity of the sixth instar larvae. We concluded that life history traits and metabolic enzymes are sensitive to Cd stress in the cotton bollworm. These parameters are potential biomarkers for monitoring environmental stress in Lepidopteran insect pests.     

棉铃虫暴发的特点,成因及治理对策

本文就１９９２年我国棉铃虫暴发成灾的特点与成因进行了详细的分析，并讨论了治理这一灾害性农业害虫的策略与方法。     

农业有害生物灾变风险预警技术的探讨

把农业有害生物灾害亦当作自然灾害的一种进行剖析并探讨其灾变风险预警技术,提出依据不同灾变过程中所表现的警源、警兆、警情等不同风险程度的各因素统计指标,精选组成灾变预警指标体系并组建多维预警逻辑模型。通过对警源、警兆、警情中主要生物与非生物因素的定量或定性分级,分析各自对灾变的影响作用,计算灾变风险预警综合指标值,确定农业有害生物灾变预警等级。据此建立了棉铃虫灾变预警与防治辅助决策系统(MLCYJJC-CDROM)并指导控害减灾,预警准确率为89.7％,使灾变警级预警更加符合实际,指导防治更有科学依据。本文还对MLCYJJC-CDROM的系统结构、信息处理与实际应用作了解析与讨论。     

Response of successive three generations of cotton bollworm, Helicoverpa armigera (Hübner), fed on cotton bolls under elevated CO2

The growth, development and consumption of successive three generations of cotton bollworm, Helicoverpa armigera （Htibner）, fed on cotton bolls grown under elevated CO2 （double-ambient vs. ambient） in open-top chambers were examined. Significant decreases in protein, total amino acid, water and nitrogen content and increases in free fatty acid were observed in cotton bolls. Changes in quality of cotton bolls affected the growth, development and food utilization of H. armigera. Significantly longer larval development duration in three successive generations and lower pupal weight of the second and third generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower fecundity was also found in successive three generations of H. armigera fed on cotton bolls grown under elevated CO2. The consumption per larva occurred significant increase in successive three generations and frass per larva were also significantly increased during the second and third generations under elevated CO2. Significantly lower relative growth rate, efficiency of conversion of ingested food and significant higher relative consumption rate in successive three generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower potential female fecundity, larval numbers and population consumption were found in the second and third generations of cotton bollworm fed on cotton bolls grown under elevated CO2. The integrative effect of higher larval mortality rate and lower adult fecundity resulted in significant decreases in potential population consumption in the latter two generations. The results show that elevated CO2 adversely affects cotton bolls quality, which indicates the potential population dynamics and potential population consumption of cotton bollworm will alleviate the harm to the plants in the future rising CO2 atmosphere.