棉铃虫卵诱集植物选择试验

在新疆莎车县,对苘麻、玉米、鹰嘴豆、红花等植物对棉铃虫卵的诱集效果进行田间比较试验。结果表明:供试植物对第2代棉铃虫卵的诱集能力明显不同,累积卵量分别为:苘麻13 018粒、鹰嘴豆3 844粒、玉米2 316粒、红花160粒、棉花120粒。苘麻诱集能力最强,持续时间最长,不但可诱集第2代棉铃虫卵,而且可大量诱集第3代棉铃虫卵。     

黄翅绢野螟对不同植物的取食和产卵选择

为明确黄翅绢野螟Diaphania caesalis对不同植物的取食和产卵选择性, 采用叶碟法、叶面积法和室内观察等方法比较分析了黄翅绢野螟对波罗蜜(‘马来西亚1号’‘海大1号’‘四季波罗蜜’)、榴莲蜜、面包树、大果榕和桑树(‘台湾长果桑’‘粤椹大10’)的取食和产卵选择性, 取食面积及初孵幼虫取食不同植物后的存活率。结果表明, 黄翅绢野螟1～2龄幼虫对波罗蜜的取食偏好不明显, 对不同植物的取食选择率差异不大; 随着龄期的增长, 3～5龄幼虫逐渐表现出偏好取食波罗蜜。黄翅绢野螟在不同植物上的日均产卵量没有显著差异, 偏好在波罗蜜和面包树上产卵, 在‘马来西亚1号’波罗蜜上着卵量占所有供试植物上的总产卵量的22.13%。各龄幼虫对不同植物的取食量随着龄期的增加而逐渐增大, 5龄幼虫进入暴食期, 对3个波罗蜜品种、榴莲蜜、面包树和大果榕的取食量无显著差异, 但显著高于2个桑树品种。初孵幼虫取食不同植物48 h后的存活率存在显著差异, 取食‘马来西亚1号’波罗蜜存活率最高(98.51%), 取食‘台湾长果桑’存活率最低(0.37%)。综上, 黄翅绢野螟偏好选择波罗蜜属植物进行取食和产卵, 对榕属大果榕存在转移为害潜在威胁, 对桑属桑树潜在为害风险较低, 研究结果可为黄翅绢野螟在不同植物上的为害风险监测和防控提供参考。     

松褐天牛成虫对不同寄主植物的选择性

从取食选择性和产卵选择性两方面研究了松褐天牛(Monochamus alternatus)对马尾松(Pinus massoniana)、湿地松(Pinus elliottii)、雪松(Cedrus deodara)和杉木(Cunninghamia lanceolata)等4种不同寄主植物的选择性。结果表明,松褐天牛成虫对不同寄主植物的取食和产卵具有明显选择性,且两者之间的选择基本一致。4种寄主植物同时存在时,马尾松为松褐天牛成虫的最嗜寄主,杉木为最不嗜寄主,两者差异显著(P<0.05)。     

Experience-altered oviposition responses to a neem-based product, Neemix, by the diamondback moth, Plutella xylostella

The oviposition responses of the diamondback moth, Plutella xylostella L., to Neemix 4.5, a neem-based oviposition repellent/deterrent, with or without previous experience were studied in the laboratory on plain aluminum foil sheets, on aluminum foil sheets coated with cabbage juice, and on cabbage plants. In the plain aluminum foil sheet experiment, the females without prior experience of Neemix (inexperienced females) deposited more eggs (66.2%) on sections with untreated sheets than on sections with Neemix-treated sheets (33.8%), indicating that the inexperienced females were significantly repelled and/or deterred by Neemix. In contrast, the Neemix-experienced females deposited more eggs (69.2-69.7%) on sections with Neemix-treated sheets than on sections with untreated sheets (30.3-30.8%), implying that the females were not repelled and/or deterred by Neemix following an experience. In the tests using egg-laying sheets coated with cabbage juice or with cabbage juice plus Neemix, the inexperienced females deposited more eggs (63.8%) on the sections with sheets treated with cabbage juice only than on the sections with sheets coated with cabbage juice and Neemix (36.2%), indicating that inexperienced females were repelled and/or deterred by Neemix. Similarly, Neemix-experienced females deposited more eggs (62.2-65.6%) on the sections with sheets treated with cabbage juice plus Neemix than on the sections with sheets treated with juice only (34.4-37.8%), suggesting that the females were not repelled and/or deterred by Neemix following an experience. On cabbage plants, inexperienced females oviposited similar numbers of eggs on both Neemix-treated (50.8%) and untreated plants (49.2%). However, the Neemix-experienced females oviposited more eggs on the plants treated with Neemix (56.3%) than on untreated plants (43.7%), indicating that the females were attracted by Neemix-treated plants following an experience. The significance of this study for applications of insect repellents/deterrents in pest management is discussed.     

温湿度、光照周期和寄主植物对小地老虎求偶及交配行为的影响

为了解温度、光照周期、相对湿度及寄主植物对小地老虎求偶及交配的影响,采用直接观察法研究这些因子对小地老虎求偶及交配的影响。结果表明,温度为25℃时,小地老虎的求偶次数、交配次数最多,求偶率、交配率最高,求偶起始时间最短,求偶持续时间、单次交配持续时间最长,分别为6.83次、1.78次、86.21%、82.32%、311.35 min、65.46 min、43.53 min,高于或低于25℃会抑制求偶及交配;光照周期为6 h∶18 h时,小地老虎的求偶次数、交配次数最多,求偶率、交配率最高,求偶起始时间、求偶持续时间、单次交配持续时间最长,分别为8.45次、2.42次、93.62%、90.63%、347.41 min、86.83 min、60.33 min,光照周期延长会抑制求偶及交配;湿度为55%时,小地老虎的求偶次数、交配次数最少,求偶率、交配率最低,求偶起始时间最长,求偶持续时间、单次交配持续时间最短,分别为4.41次、1.34次、72.65%、70.45%、325.78 min、53.45 min、31.34 min,湿度升高会促进求偶及交配;放玉米叶片时,小地老虎的的求偶次数、交配次数最多,求偶率、交配率最高,求偶起始时间最短,求偶持续时间、单次交配持续时间最长,分别为8.87次、2.73次、95.32%、93.26%、262.42 min、85.52 min、64.67 min。     

寄主植物上喷药对大螟产卵选择性的影响

为明确稻田适量喷施保护性农药是否影响周边香根草对水稻螟虫的诱集效果,通过室内盆栽试验测定了在水稻和香根草上分别喷施氯虫苯甲酰胺对大螟成虫趋性及产卵选择性的影响。结果表明:在水稻上喷药后第1天,栖息在香根草上的大螟雌、雄成虫总量分别为4.2头和3.8头,显著高于水稻上雌、雄成虫的总量1.00头和0.60头;在水稻上喷药后1~3 d接入大螟,在水稻上不产卵,直到第6天才出现卵块;喷药后6 d和12 d接入大螟,在香根草上的卵粒数分别为287.2粒和309.2粒,显著高于其在水稻上的57.2粒和81.4粒,约为水稻上的5.0倍和3.8倍。在香根草上喷药后1~3 d接入大螟,成虫选择水稻居多,在香根草上的产卵量为0;喷药后6 d接入大螟,成虫对2种寄主植物的选择性无显著差异;喷药后12 d接入大螟,在香根草上的成虫数量为9.8头,约为水稻上的2.5倍,产卵量也约为水稻上的1.9倍,二者均差异显著。表明香根草喷施氯虫苯甲酰胺后其对大螟的诱集作用有一定影响,但这种影响会随着施药时间的延长而逐渐减弱。     

A comparison of the translocation within plants of pyroxychlor and a 6-amino analogue

The uptake and translocation within tomato plants of pyroxychlor (2 chloro-6-methoxy-4-(trichloromethyl) pyridine) and the 6-amino analogue were compared. Both fungicides were transported symplastically but the amino analogue was more efficiently taken up by foliage with much less loss by volatilization from leaf surfaces. Pyroxychlor was taken up more efficiently by root treatment than the amino analogue but the latter was more readily transported to above-ground parts of plants. The uptake of both fungicides appears to be passive, based on temperature studies, and differences between analogues may be due to relative lipophilicity. Uptake and efflux studies with potato tuber tissue confirmed passive accumulation against a concentration gradient by cells. The concentration against a gradient was less and the release from tissue more complete with the amino analogue which is logically correlated with its more ambimobile pattern of transport.     

寄主植物对棉蚜乙酰胆碱酯酶的影响

通过生物测定和生化分析研究了5种不同寄主植物上的棉蚜种群对灭多威的敏感性，乙酰胆碱酯酶（AChE)活性及灭多威对AChE的抑制作用，结果发现，取食石榴和花椒的棉蚜AChE活性最高，是冬青上棉蚜（最低）的2．00倍和3．33倍，说明寄主植物可以影响棉蚜AChE的活性，灭多威对不同寄主植物上的棉蚜个体的AChE进行抑制后，发现棉花和冬青上的棉蚜种群中AChE对灭多威不敏感的棉蚜个体多于花椒，木槿和石榴上的棉蚜种群，这与棉花及冬青上的棉蚜对灭多威耐药性较其它三种强的趋势近似，表明AChE敏感度的降低是棉蚜对灭多威产生抗药性的原因之一。     

两种产卵引诱物质刺激下橘小实蝇雌成虫的转录组分析

为阐明橘小实蝇Bactrocera dorsalis感受2种气味物质γ-辛内酯和β-石竹烯的分子机制,于室内测定记录其已交配雌成虫的触角电位（electroantennogram,EAG）反应和行为,利用RNA-Seq测序技术测定其已交配雌成虫在2种气味物质刺激下的头部组织转录组并进行比较分析,应用实时荧光定量PCR对部分化学感受基因进行验证。结果表明,橘小实蝇已交配雌成虫对γ-辛内酯和β-石竹烯2种气味物质均有浓度依赖性反应,随着浓度增大,EAG反应值有增大趋势,且2种气味物质均对橘小实蝇已交配雌成虫具有明显的引诱作用。γ-辛内酯刺激后橘小实蝇已交配雌成虫的头部转录组中共有851个差异表达基因,包括20个化学感受基因,其中有261个基因上调表达,590个基因下调表达;而β-石竹烯刺激后共有523个差异表达基因,包括15个化学感受基因,其中162个基因上调表达,361个基因下调表达。实时荧光定量PCR检测结果证实,分别有4个和6个化学感受基因可能与橘小实蝇雌成虫对γ-辛内酯和β-石竹烯的感受相关。表明橘小实蝇雌成虫感受γ-辛内酯和β-石竹烯的分子机制可能是由多种化学感受基因共同参与完成。     

双钩巢粉虱产卵分泌物的化学成分

双钩巢粉虱Paraleyrodes pseudonaranjae Martin原产于南美洲,现已分布于美国的佛罗里达、夏威夷和中国的香港、广东、广西、海南等地。这种粉虱的产卵方式与螺旋粉虱Aleurodicus disperses Russell等相似,卵粒以白色的分泌物覆盖。本文采用气相色谱/质谱联用技术研究了双钩巢粉虱产卵分泌物的化学成分。以甲酯化和未甲酯化两种处理方法测定表明,该粉虱产卵蜡泌物主要由一系列烃类、酯类及脂肪酸构成,同时还含有少量的酮类、酚类及醇类。主要成分是1,2-苯二羧酸二异辛酯、15-甲基-十六酸、邻苯二羧酸单(2-乙基己基)酯、3,8-二甲基十一烷、1-乙酰基-1,2-环氧戊烷等。还将该虫产卵分泌物的化学成分与螺旋粉虱作了对比,讨论了产卵蜡泌物在分类及防治中的意义。     

A note on the mosquito oviposition pheromone

Mosquitoes of the genus Culex, e.g. Culex quinquefasciatus, release a volatile pheromone from their eggs that induces gravid females to oviposit around the pheromone source. Enantioselective synthesis by the Sharpless epoxidation method and chiral gas chromatography showed the major pheromone component to be (?)-(5R,6S)-6-acetoxy-5-hexadecanolide. Shortening the alkyl chain resulted in a loss of behavioural activity, whereas perfluorination of the alkyl chain or substitution of the acetoxy groups with the trifluoroacetoxy group gave active analogues. A simple large scale synthesis was devised to provide material for a fìeld trial. The pheromone, formulated in effervescent tablets, was used to concentrate oviposition in specific breeding sites where the larvae were controlled with a juvenoid-type insecticide.     

外源注射PBAN对甜菜夜蛾求偶、交配与产卵作用初步研究

在光期对甜菜夜蛾雌蛾注射人工合成的小分子性信息素合成激活肽PBAN,并观察其求偶、交配与产卵行为。结果表明,人工合成甜菜夜蛾PBAN适宜的注射浓度为3.5 pmol/μL。与注射蒸馏水对照相比,注射PBAN能够有效促进雌蛾提前发生求偶行为,且持续交配时间显著延长,单雌产卵量也显著增加。但与空白对照(未注射)相比,尽管注射PBAN的雌蛾求偶行为有所提前,但交配率和产卵量均明显低于对照组。初步说明外源注射PBAN对甜菜夜蛾求偶、交配与产卵行为均有重要的影响作用,特别是引起雌蛾求偶行为明显提前,甚至在光期观察到注射PBAN的雌蛾出现求偶行为。这为验证甜菜夜蛾PBAN的功能提供了依据,也为遗传改造PBAN基因干扰成虫交配达到无公害防治开拓了思路。     

Impact of post-emergence herbicides on weed community diversity within conservation-tillage systems

The influence of herbicides on weed community dynamics is an issue of agroecological concern. A field study was initiated in 1986 with zero-, minimum-, and conventional-tillage systems. In 1989 and 1990, the fourth and fifth years of study, weed community diversity and relative composition were assessed prior to and following the application of post-emergence non-residual herbicides. Weed communities were assessed at the level of tillage system to balance the effect of different crop sequences and crop-herbicide combinations within each comparison. In general, herbicides did not reduce community diversity when compared by Shannon's H’and dominance-diversity curves. An increase in species richness and evenness, as assessed by Shannon's E and Margalef's D_MG occurred in some cases. Differences in relative community composition among tillage systems were apparent before the application of herbicides, but disappeared following herbicide application. The use of herbicides in this study reduced weed densities, maintained weed diversity, and inhibited community changes that were due to changing tillage systems.     

Depolymerization of the actin cytoskeleton induces defense responses in tobacco plants

Tobacco leaf sections were treated with actin inhibitors, i.e., cytochalasins, to determine the effects of actin depolymerization on tobacco defense responses. Inoculation of the leaf sections with the pathogen Erysiphe cichoracearum, depolymerized the actin cytoskeleton, priming the cells for a hypersensitive response-like cell death. Further, expression of the acidic PR1 and PR2 genes were induced in cytochalasin-treated leaf sections. The intensity of the cytochalasin effects on the defense responses was closely correlated with the extent of actin depolymerization. This suggests that plant cells may perceive perturbation of the actin cytoskeleton, and this stimulus may trigger plant defense responses.     

3种金龟甲对寄主植物的行为反应研究

选取不同寄主植物叶片对暗黑鳃金龟、铜绿丽金龟、大黑鳃金龟的雌雄虫进行室内嗅觉试验,结果表明不同植物叶片对上述几种金龟甲的引诱作用差异较显著。大黑鳃金龟雌虫对榆树的选择反应率和选择系数最高,分别为81%和0.61; 雄虫对沟叶结缕草趋向较强,选择反应率和选择系数为93%和0.85。榆树对暗黑鳃金龟雌虫的引诱效果显著,其选择反应率和选择系数达到80%和0.59; 雄虫对桑树有强趋性,选择反应率和选择系数分别高达87%和0.74。女贞对铜绿丽金龟雌雄虫均有好的引诱活性,雌虫选择反应率和选择系数达到79%和0.58,雄虫分别为72%和0.44。以上寄主植物对金龟甲诱集作用的研究不仅对现阶段农田防治金龟甲有重要指导意义,而且还可为金龟甲生防植物的选择及食诱剂的研制和开发提供知识储备。