甘蔗二点螟在湖南的发生特点

甘蔗二点螟（ＣｈｉｌｏｉｎｆｕｓｃａｆｅｌｌｕｓＳｕｅ－ｌｌｅｎ）以幼虫越冬。低龄幼虫在种蔗和盖膜宿根蔗内，８℃以上温度即可取食为害，可成为有效虫源。进入滞育的龄期为５龄，一旦滞育，幼虫则不能老熟，但仍可取食和脱皮。老熟幼虫可以休眠方式越冬。预蛹期前有３～５天的后补营养期，蛹历期６～１８天。年发生代数ｌ～４代。甘蔗二点螟在湖南的发生特点@黄河清     

第一代甘蔗二点螟的预测预报及防治

甘蔗二点螟是甘蔗的主要害虫,在湘北蔗区,每年发生３～４代,以第一代发生为害最重,如防治不好,每年造成的枯心率在５～２０％,最高丘块可达５０％以上。二点螟在甘蔗上的发生为害比较复杂和特殊。一是发生盛期长,盛期内高峰多。这是由于二点螟主要在蔗克、种蔗茎内以幼虫越冬,甘蔗播种后,上部蔗碴、上面蔗克及地膜覆盖的种茎内的越冬幼虫由于温度较高发育进度快Ｚ而土壤下面的蔗朝、下部蔗碴、套作甘蔗茎内的越冬幼虫由于温度低,发育进度慢。在本地,越冬代成虫发生盛期一般在４月２５日至５月１５日,长达２０多天,最早在４月１…     

烟草粉斑螟Ephestia elutella(Hübner)生活史与种群动态研究

为研究烟草粉斑螟Ephestia elutella (Hübner)在陕西关中的发生规律,于1998-2001年采用室内饲养与性诱捕器监测相结合的方法,持续调查了烟草粉斑螟年生活史和种群数量动态.结果表明:1)烟草粉斑螟在关中地区1年可发生2-3代,主要以老熟幼虫在烟仓中越冬;2)成虫3月下旬开始羽化,全年有3个发生高峰期,越冬代、第1代和第2代成虫的羽化高峰期分别出现在5月中旬、8月上旬和9月上旬;3)老熟幼虫有3个明显的迁移活动期,分别出现在4月上中旬、7月上旬和10月中下旬;4)越冬代成虫的发生期受贮藏环境温度的影响,幼虫的活动规律则不仅与发育期有关,还受人为活动的影响.据此提出了相应的防治措施.     

豫中地区烟蚜茧蜂田间越冬及滞育调查分析

为明确豫中地区烟蚜茧蜂田间越冬场所和滞育特性,对烟蚜茧蜂僵蚜田间越冬情况进行了调查,并采集样本进行鉴定,同时分析了烟蚜茧蜂越冬滞育规律和越冬虫态。结果表明,豫中烟区烟蚜茧蜂以僵蚜形式越冬,不能以成蜂在野外越冬,其中以蛹在僵蚜中越冬的比例较高,平均为47.95%;其次是以老熟幼虫在僵蚜中越冬,平均为41.48%;少数以预蛹状态在僵蚜体内越冬。越冬寄主主要集中在白菜、萝卜等蔬菜上,少数在油菜、小麦和杂草上。从当年11月至次年3月中旬,烟蚜茧蜂田间越冬滞育率总体呈现先上升后下降的变化趋势,滞育率最高可达64.0%,滞育持续期可维持3～5个月。     

二点螟发生与测报的研究

二点螟又名粟灰螟。在长江以南主要为害甘蔗,长江以北主要为害粟及糜子、高粱、玉米等。二点螟在浙江镇海、温岭等县一年发生3—4代,以第三代老熟幼虫或第四代2—5龄幼虫越冬,以为害甘蔗为主,第一、二代为害造成枯心。据调查,第一代枯心率达14.2%,     

廉江市甘蔗条螟严重发生的成因及防治对策

对廉江市今年7－8月份历史上首次出现甘蔗条螟（第3代幼虫）严重为害进行了全面调查,计在15个甘蔗生产乡镇的7个品种进行条螟为害的主要受害指标螟害节及枯梢调查,提出了条螟严重发生的成因及防治对策。     

转Bt基因甘蔗对甘蔗条螟的抗虫性评价

通过研究转Bt基因甘蔗株系(B2、B14和B17)对甘蔗条螟的幼虫取食行为、致死率、产卵选择性和孵化率的影响,并结合室外田间抗性指标调查,评价转基因甘蔗对甘蔗条螟的抗性强弱。结果表明,对甘蔗条螟的抗虫性以B17为最强,其次是B14和B2。其中,各株系对条螟在产卵选择性和孵化率方面差异不显著,而在幼虫取食面积和幼虫致死率方面,B17、B14、B2均与对照之间差异显著。     

综合防治蔗螟效果好

蔗螟是甘蔗的主要害虫。我场主要发生二点螟、大螟和条螟。以二点螟居多,占80％以上,年发生四代,为害严重。为了防治螟害,确保甘蔗高产丰收,我场主要采取:处理残渣压基数,套种轮作避害虫,点灯诱蛾防产卵,掌握虫情巧用药,放蜂杀卵保丰收等有效的综合防治措施,收到了明显的效果。枯心率由1975年的11.2％压低到2.8—3.78％。现将技术措施介绍如下: 一、处理残渣压基数蔗螟的越冬基数的大小,是决定第一代螟     

甘蔗条螟的人工饲养技术研究

研究了甘蔗条螟不同饲养方法对其生长发育生物学指标的影响。结果表明:甘蔗苗叶片作为卵卡在产卵量和孵化率方面均明显高于蜡纸和白纸,而蜡纸和白纸之间无显著性差异。在湿度为60%~80%时,甘蔗条螟卵孵化率随相对湿度升高而提高。用养虫盒饲养甘蔗条螟所得幼虫各指标优于试管和玻璃缸饲养。甘蔗条螟经室内人工饲养4代后,各项生物学指标稳定,种群未出现退化现象。本研究结果为室内大规模饲养甘蔗条螟提供了技术支持。     

甘蔗制糖文摘

新台糖２２号引种总结──卢昌，甘蔗，２００１，８（４），５４～５６ 两年试验结果表明，新台糖２２号主要农艺性状较好，公顷有效茎、蔗茎产量和含糖量比桂糖１１号有明显的优势，具有较大的丰产高糖潜力．新台糖２０螟虫防治试验初报──邓展云等，甘＄，２００１，８（４），５７～６０ 本文探讨了新台糖２０号螟虫的各种防治方法．结果表明，按测报施药及投入赤眼蜂、性诱剂可有效减轻枯心率，降低螟害株（节）率，建议生产上以这两种防治方法为主．条螟发生规律──黄河清等，甘蔗，２００１，８（４），２０～２３ 条螟属兼性滞育…     

性诱剂诱杀法防治甘蔗条螟应用技术研究

【目的】为了探索甘蔗条螟性诱剂诱杀防治的田间使用技术,确定最优防控处理面积和防控时间。【方法】通过实施不同面积比例的甘蔗条螟性诱剂诱杀试验,比较3种布盆密度条螟诱杀处理效果,分别从条螟诱杀蛾量、螟害株率和防治成本3方面进行评价各处理的优劣。【结果】试验结果显示:C处理(1 hm2/盆)和B处理(0.67 hm2/盆)诱杀蛾量差异不显著,但与A处理(0.33 hm2/盆)差异显著,B处理和A处理差异不显著;A处理和B处理的螟害株率相对防效差异不显著,但2处理与C处理差异显著;防治成本由高到低排列为A处理(0.33 hm2/盆)B处理(0.67 hm2/盆)C处理(1 hm2/盆);综合评价认为B处理为较优条螟诱杀防治处理。     

Diapause induction in Ephestia elutella (Hübner) and Plodia interpunctella (Hübner) (Lepidoptera,Pyralidae) with a dawn-dusk lighting system

The incidence of diapause in larvae of Ephestia elutella and Plodia interpunctella under two light systems operated by solar switches was observed at 25°C. Both switches gave progressively shortening daylength, as would be experienced from early July onwards at a latitude of 52°N. One of the light systems incorporated a device, which took 60 min to change to, or from, full light to near darkness, giving a dawn and a dusk with the photophase. The other was controlled directly by the time switch itself, without any extended periods of changing intensity.Maximal percentages of E. elutella larvae entering diapause under the two systems were obtained with photoperiods half way through development of less than 13 hr 25 min and 13 hr 10 min respectively, measurements of photoperiod in the dawn-dusk system including the 1 hr dawn and 1 hr dusk. The mean critical photoperiod, here defined as that photoperiod giving half the maximum percentage of insects that enter diapause in response to photoperiod at a fixed temperature, was found to be 14 hr 15 min under the dawn-dusk system, and 14 hr 5 min under the other shortening daylength system. Comparison of the above results with the incidence of diapause under a series of fixed daylengths confirmed that the principal sensitive phase in E. elutella occurred early in the last larval instar.Over 70 per cent emergence occurred in batches of P. interpunctella within 7 weeks of egg laying under all lighting conditions tested. Maximal percentages of larvae entered diapause after rearing in total darkness, continual light, or photoperiods of 13 hr or less. The sensitive phase occurred around 8 days after hatching at 25°C, and the mean critical photoperiod was found to be about 13 hr 15 min under both shortening daylength systems, and under fixed photoperiods. Photoperiods of over 13 hr, or increased temperature, appeared to inhibit diapause in P. interpunctella. Light intensities below 1 lux influenced diapause in both species.     

球孢白僵菌高孢粉对2种甘蔗螟虫幼虫的致病性研究

甘蔗条螟和甘蔗二点螟是为害甘蔗最重要的害虫。为探索一条可持续、环保型的新型防治方法,本文利用广谱杀虫性球孢白僵菌在室内对2种甘蔗螟虫开展生测实验。实验证明,侵染天数和侵染浓度均对2种害虫有显著性影响,各种浓度白僵菌对2种甘蔗螟虫均有致病效果,其中甘蔗二点螟幼虫相比甘蔗条螟更快被侵染并死亡,白僵菌对不同甘蔗害虫有显著性差异。本研究结果为白僵菌在甘蔗上的利用提供参考,以加快微生物生防技术在甘蔗害虫防治上的推进。     

The incidence of diapause in seventeen populations of the flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

Samples of Ephestia kuehniella were examined for diapause at 20 and 25°C in continuous darkness, continuous light and three other photoperiods. The samples came from five flour mills and five unheated stores in England, and from Scotland, Egypt, Finland and Japan, together with three laboratory reared stocks. Some larvae entered diapause in all but three of the English stocks, in all stocks from other countries, and in a 10-yr old laboratory stock from Japan but not in two other stocks reared in the laboratory for over 30 yr. In continuous darkness at 25°C, the incidence of diapause exceeded 10% in eleven stocks, 25% in eight, and 50% in three stocks, while in darkness at 20°C the proportions were usually much smaller. In other light regimes there was a much lower incidence of diapause, 10% being reached in only six experiments out of more than eighty. Markedly more larvae entered diapause when reared on the maize or wheat flour available in mills than on a nutritious laboratory diet of wheatfeed, glycerol and yeast.     

Studies on the isolation of diapause and non-diapause strains of Trogoderma granarium everts (Coleoptera,Dermestidae)

By continuous mass selection and inbreeding, populations of Trogoderma granarium larvae that showed nearly 100 per cent incidence of diapause or 100 per cent freedom from diapause when reared in isolated or crowded conditions on wheat flour at 30°C, were obtained. The progress of selection showed that diapause is a polygenic character. The density-dependent diapause was manifested even in populations in which the density-independent diapause was totally eliminated by selection. In standard experimental populations most larvae enter diapause at 30°C and pupate promptly at 35°C when reared in isolation on a suboptimal diet viz. wetted-dried wheat flour. In contrast, the selected non-diapause population neither entered diapause at 30°C nor pupated at 35°C when fed on this diet; instead, at both the temperatures most larvae either died in the first stadium or survived for long periods with little gain in weight.     

Temporal changes in reproductive hormones and conceptus-endometrial interactions during embryonic diapause and reactivation of the blastocyst in European roe deer (Capreolus capreolus)

The roe deer blastocyst is in diapause between August and December, after which time it expands and elongates rapidly before implantation. Blood samples were taken from 30 animals to define temporal changes in reproductively important hormones to investigate the physiological cues present at embryo reactivation. In 15 of these animals, changes in uterine and conceptus protein synthesis and secretion, and luteal progesterone release during diapause and reactivation, were assessed after culture of these tissues in vitro. Oestradiol concentrations remained low during diapause (1.07 +/- 0.4 pg ml(-1)) and expansion (1.2 +/- 0.4 pg ml(-1)) but increased by 30 times at trophoblast elongation (49.17 +/- 0.37 pg ml(-1)). Prolactin remained at basal concentrations (4.69 +/- 0.86 ng ml(-1)) and increased after implantation (12.34 +/- 2.71 ng ml(-1)). Peripheral progesterone concentrations and luteal progesterone release remained constant throughout diapause, reactivation and implantation (peripheral progesterone: 3.82 +/- 1.97 ng ml(-1); luteal progesterone: 6.72 +/- 0.81 ng mg(-1) protein). Incorporation of a radiolabel into conceptus secretory proteins increased by four times at expansion compared with diapause, whereas incorporation into endometrial secretions remained constant. At elongation, incorporation into endometrial secretions increased two times and conceptus secretions increased 32 times. Two-dimensional electrophoresis and fluorography showed that the profile of endometrial secretory proteins was constant until implantation when qualitative changes were evident. Although a role for an endocrine maternal trigger of reactivation from diapause cannot be dismissed, these data provide no supporting evidence and indicate that the conceptus itself may drive reactivation.     

The influence of photoperiod on the life-cycle of Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae)

Diapause in fully grown larvae of Ectomyelois ceratoniae was induced by low temperature and short photoperiods. When larvae were reared at 30°C, 70% r.h. there was no diapause in a light regime of 12 hr light followed by 12 hr darkness (12L/12D), and only 20% entered a weak diapause in continuous darkness. However, at 20°C, 70% r.h. there was no diapause in 16L/8D but almost all larvae entered diapause in 12L/12D. At 20°C diapause delayed adult emergence by an average of 111 days, compared with about 50 days at 30°C. Survival to adult at 30°C was 75% or more at most photoperiods, but at 12L/12D and 13L/11D it was less than 50%. At 20°C survival was about 70% at the two photoperiods tested.

A slight effect of photoperiod on non-diapause growth rates was observed. Above 16 hr light longer photoperiods reduced the mean developmental period from egg hatch to adult emergence, by 4 days at 20L/4D and 6 days at 24L/0D.

The significance of diapause in this species in relation to its potential as a pest is discussed.     

A review of diapause and tolerance to extreme temperatures in dermestids (Coleoptera)

Numerous species in Family Dermestidae (Coleoptera) are important economic pests of stored goods of animal and vegetal origin, and museum specimens. Reliance on chemical methods for of control has led to the development of pesticide resistance and contamination of treated products with insecticide residues. To assess its practicality as an alternate method of control, we review the literature on the tolerance of dermestids to extreme hot and cold temperatures. The information for dermestid beetles on temperature tolerance is fragmentary, experimental methods are not standardized across studies, and most studies do not consider the role of acclimation and diapause. Difficulties in determining the diapause status of dermestid larvae may explain the lack of studies. The few studies that do examine these factors show that they can greatly increase tolerance to cold temperatures. The use of extreme temperatures will need to target the most tolerant life stage, which for dermestids at cold temperatures will potentially be the cold-acclimated individuals in diapause. The development of effective protocols will be facilitated by studies that clearly and completely describe experimental and statistical methods, consider factors (life-stage, acclimation, diapause) that increase tolerance to extreme temperatures, and assess the mortality at various temperatures to develop mathematical models.     

Embryonic diapause and its regulation

Embryonic diapause, a condition of temporary suspension of development of the mammalian embryo, occurs due to suppression of cell proliferation at the blastocyst stage. It is an evolutionary strategy to ensure the survival of neonates. Obligate diapause occurs in every gestation of some species, while facultative diapause ensues in others, associated with metabolic stress, usually lactation. The onset, maintenance and escape from diapause are regulated by cascades of environmental, hypophyseal, ovarian and uterine mechanisms that vary among species and between the obligate and facultative condition. In the best-known models, the rodents, the uterine environment maintains the embryo in diapause, while estrogens, in combination with growth factors, reinitiate development. Mitotic arrest in the mammalian embryo occurs at the G0 or G1 phase of the cell cycle, and may be due to expression of a specific cell cycle inhibitor. Regulation of proliferation in non- mammalian models of diapause provide clues to orthologous genes whose expression may regulate the reprise of proliferation in the mammalian context.