Increase in Cladosporium spp. populations and rot of wine grapes associated with leaf removal

Leaf removal reduces the epiphytic populations of several filamentous fungi found on grapevine (Vitis vinifera). Consequently this practice is used to prevent foliar diseases of grapevines and rots of grapes. In this study, the effects of leaf removal on Cladosporium rot (Cladosporium cladosporioides and Cladosporium herbarum), which often affects ‘Cabernet Sauvignon’ in Chile, were characterized. The effects of leaf removal on epiphytic populations of Cladosporium spp. on grape berry surfaces and on Cladosporium rot development were investigated. Three leaf removal treatments were compared: (i) severe leaf removal, where leaves from two to three nodes above, opposite and from all nodes below clusters were removed; (ii) mild leaf removal, where leaves opposite each cluster were removed; and (iii) no leaf removal. Regardless of the leaf removal treatment, low population levels of Cladosporium spp. were detected early in the ontogenic development of grape berries which increased as the berries matured, reaching maximum populations on overripe berries. Based on our results, severe leaf removal favors the growth of Cladosporium spp. on grape berries and increases the prevalence of Cladosporium rot at harvest. This increase in Cladosporium spp. was correlated with an increase in lenticel damage in ‘Cabernet Sauvignon’ and ‘Sauvignon blanc’ vines subjected to severe leaf removal. Considering that Cladosporium rot significantly reduces yield and wine quality, farmers should avoid continuous exposure of grape clusters to sunlight in order to prevent severe outbreaks of Cladosporium rot.     

Survival and developmental impairment induced by the trypsin inhibitor bis-benzamidine in the velvetbean caterpillar (Anticarsia gemmatalis)

Proteinase inhibitors are potential insect control agents, but insect adaptation to these compounds is one of the main limitations for their potential use as such. The velvetbean caterpillar (Anticarsia gemmatalis Hübner) (Lepidoptera: Noctuidae) is a key soybean pest species well-adapted to its prevailing (serine-) proteinase inhibitors, particularly trypsin-like inhibitors. The recognition of proteinase inhibitors with insecticidal activity towards such pest species is therefore challenging and important as a basis for the development of mimetic peptides with potential use as biorational insecticides. Thus, bis-benzamidine was tested against the velvetbean caterpillar with the expectation of greater insecticidal activity of this more potent trypsin inhibitor than the negligible effects observed with other natural and synthetic trypsin inhibitors. Bis-benzamidine ingestion by the caterpillars led to higher survival time with increased doses up to 76 ppm, but drastically reduced survival time at higher doses (over 150 ppm). Insects exposed to bis-benzamidine doses of up to 76 ppm exhibited extended larval development and decreased pupa weight. Increased doses of this trypsin inhibitor led to increased diet consumption and protein digestibility during the larval phase, but drastically compromised the proteolytic activity in the caterpillar gut. These results indicate that, unlike benzamidine, another related synthetic trypsin inhibitor, bis-benzamidine exhibits insecticidal activity towards the velvetbean caterpillars at doses as low as 9.5 ppm in the insect diet due to suppression of gut proteinase activity despite the compensatory feeding. Such compensatory feeding may however increase insect damage in the field by more tolerant individuals and should be the object of further study.     

基于AVR单片机的害虫耐热性试验装置设计

掌握农产品目标害虫的耐热性对于确定热处理杀虫方法中热处理温度和时间非常重要,为此设计了一套加热杀虫过程中控制加热速度和加热温度的试验装置。以AVR Atmega16单片机为控制器,Pt100为温度传感器,采用脉宽调制原理设计了害虫耐热性试验装置的温度检测和控制电路;利用单片机C语言设计了下位机控制程序,利用VB语言设计了上位机监控软件(包含数据输出功能)。系统测试结果表明,10～70℃范围内的温度检测精度为0.2℃,温度控制精度为0.1℃,加热速度可在0～15℃/min范围内任意设定。     

Feeding behavior of a potential insect pest, Lygus hesperus, on four new industrial crops for the arid southwestern USA

Camelina (Camelina sativa), guayule (Parthenium argentatum), lesquerella (Physaria fendleri), and vernonia (Centrapalus pauciflorus [formerly Vernonia galamensis]) are either under limited commercial production or being developed for production in the southwestern USA. Insect pests are a potential economic threat to all these new crops, with Lygus hesperus, the western tarnished plant bug, among the most prominent due to its regional abundance and propensity to feed on reproductive plant tissue. The objectives of this study were to establish baseline data on the feeding behavior and potential impact of L. hesperus on camelina, guayule, lesquerella and vernonia. Behavioral observations of adult females and males, and nymphs of this insect were made in the laboratory. Insects spent ≈35% of their time either probing (=tasting) or feeding on various reproductive and vegetative tissues of guayule, lesquerella or vernonia, but only 20% on camelina. When insects did probe and feed they preferred reproductive tissues, primarily flowers and siliques/achenes, and there were differences in these behaviors relative to crop but not generally to insect stage or sex. Insects probed and fed more on flower tissue of guayule and vernonia compared with camelina and lesquerella, and more on siliques of lesquerella compared with achenes of vernonia. When probing and feeding on vegetative tissue, there was generally a preference for stems compared with leaves in all crops except guayule. Results show that L. hesperus will readily feed on the economically important tissues of all crops, and although research has shown that this feeding did not consistently affect lesquerella yield, further work will be needed to determine if such feeding poses a risk to commercial production of camelina, guayule or vernonia.     

AM真菌介导垂穗披碱草抗虫作用研究

为探究AM真菌参与垂穗披碱草间防御信号介导的抗虫机制,本研究设计了4个处理,分别为A：有菌丝和根连接、B：有菌丝连接无根连接、C：无菌丝和根连接、D：旋转后无菌丝和根连接。于分蘖期进行试验,测定菌根侵染率,收集和分析虫害后挥发物的嗅觉行为反应。结果表明：各处理间差异显著,且对蝗虫有一定的负趋性;有菌丝连接比无菌丝连接的植株产生的挥发性物质（Volatile organic compounds Vocs）含量和种类多;蝗虫采食供体垂穗披碱草诱导受体产生的有效成分包括（E）-2-己烯-1-醇（（E）-2-hexen-1-ol）、芳樟醇（Linalool）、十四烷（Tetradecane）、香芹酚（Carvacrol）、苯甲醛（Benzaldehyde）、石竹烯（Caryophyllene）等物质。证明AM真菌可作为垂穗披碱草株间交流的通道。     

太阳能杀虫灯防控技术在苜蓿生产中应用初探

通过在黑龙江省齐齐哈尔市苜蓿（Medicago Sativa）生产田中,开展利用太阳能杀虫灯和化学药剂防治虫害研究,对比二者之间的优劣性,探究太阳能杀虫灯防治苜蓿虫害技术。结果表明：无论太阳能杀虫灯还是化学药剂,均能有效防治当地6种主要的苜蓿虫害,包括苜蓿蓟马（Odontothrips phaleratus Haliday）、豆无网长管蚜（Acyrthosiphon pisum Harris）、牧草盲蝽（Lygus pratensis Linnaeus）、叶象甲[Hypera postica （Gyllenhal）]、草地螟（Coxostege sticticatis Linnaeus）、潜叶蝇（Phytomyza utricornis Meigen）。分析其防治成本及效益,太阳能杀虫灯防治每公顷干草增产1535 kg,增收2974元;化学药剂防治每公顷干草增产917 kg,增收1551元,二者无显著差异。但就综合生态效益和经济效益而言,太阳能杀虫灯防治技术优于化学药剂,可以在苜蓿种植中推广应用。     

昆虫干细胞研究进展

干细胞是一类具有自我更新和分化潜能的细胞,按照其来源可分为胚胎干细胞和成年干细胞。昆虫中也同样存在多种干细胞。开展昆虫干细胞自我更新、发育命运决定、分化潜能等特性以及其与周围微环境相互关系的研究,对农林害虫的生物防治、经济昆虫的遗传育种以及一些生物反应器材料的利用,甚至对于人类疾病的治疗等都具有重要意义。以模式生物果蝇为主,介绍了昆虫干细胞的相关研究进展,重点集中在果蝇各种组织干细胞的鉴定与识别方面,包括研究较成熟的生殖腺内干细胞、中肠干细胞、马氏管干细胞、神经母细胞和造血干细胞。同时介绍了对干细胞维持起重要调控作用的各种信号途径的研究进展。这些昆虫干细胞的研究成果将为开展家蚕等鳞翅目昆虫的干细胞研究提供启示。     

昆虫醛氧化酶研究进展

醛氧化酶(aldehyde oxidase,AO;EC1.2.3.1)是钼-黄素酶家族(molybdo-flavoenzyme family,MFE)中的一类蛋白,通常是由2个相同亚基形成的同源二聚体构成,每个亚基具有2个[2Fe-2S]氧化还原中心、1个黄素辅因子(FAD)和1个底物结合域,与钼-黄素酶家族的另一成员黄嘌呤氧化还原酶结构特征相似。AO可氧化醛类物质和将含氮杂环物质羟基化,在机体代谢过程中的作用至关重要。对醛氧化酶的结构、催化反应机制、系统进化等研究结果进行了综述,重点介绍了昆虫醛氧化酶的研究进展。     

树干注射7种生物源杀虫剂对松梢象的防治效果

为探索对松梢象(Pissodes nitidus)的有效防治方法,选择高渗苯氧威、猎擒、灭蚜风暴、高效氯氰菊酯、阿维菌素、啶虫眯乳油、苦参素7种生物源杀虫剂及昆虫生长调节剂,进行室内水培红松(Pinus koraiensis)主梢及林间红松树干打孔注射防治试验。室内试验结果表明,高渗苯氧威3 500倍液、猎擒3 000倍液及灭蚜风暴4 000倍液校正死亡率达到70%以上,且3种药剂的不同处理间防治效果差异不显著(p0.05);将这3种药剂用于林间一次性防治,高渗苯氧威的5倍液、10倍液、15倍液及猎擒5倍液和灭蚜风暴5倍液的松梢象校正死亡率均达到80%以上。利用高效氯氰菊酯、阿维菌素、啶虫眯乳油3种药剂进行林间连续2年防治,每年防治1次,结果表明:第1年林间防治效果,除高效氯氰菊酯15倍液外,校正死亡率均达到60%以上,与对照组差异极显著(p0.01);其中阿维菌素和啶虫眯乳油5倍液、10倍液的校正死亡率均达到80%以上;第2年林间防治效果高于第1年,松梢象校正死亡率均达到90%以上;连续防治后松梢象对红松危害株率小于4%,被害株率防治效果达到了84.9%~88.9%。因此,高渗苯氧威5倍液、10倍液和15倍液,猎擒5倍液,灭蚜风暴5倍液,阿维菌素和啶虫眯乳油5倍液和10倍液均可有效控制松梢象的危害。