几种植物气味挥发物与性信息素组合对棉铃虫触角电位反应的影响

为了测定几种植物气味挥发物对棉铃虫及其性信息素的影响,利用电生理的方法进行测定。结果表明：除了甜瓜以外,植物挥发物均可刺激棉铃虫产生触角电位反应,且随着浓度的增加,电位值呈逐渐上升趋势。试验所测植物挥发物对性信息素的影响结果表明：组合比例不同影响效果不同,部分组合提高性信息素的电位值,部分组合减弱性信息素的电位值,且苯乙醛的存在可能影响苯甲醛和水杨酸组合对性信息素的作用效果。以上结果将为下一步研究开发棉铃虫性信息素的增效剂提供科学依据。     

斜纹夜蛾对植物挥发物及其与性信息素组合的触角电位反应

以福建省晚熟龙眼品种‘立冬本’果实为材料,研究果实采前套袋时期（盛花后80 d、95 d、110 d）对龙眼果实品质和采后贮藏特性的影响。结果表明：果实采前3个不同套袋时期都可以可明显改善龙眼果实的外观品质,提高果肉可溶性固形物、总糖、维生素C和可溶性蛋白质等营养物质含量,降低可滴定酸含量。果实采前套袋提高了与龙眼果皮褐变密切相关的总酚含量和过氧化物酶活性,促进龙眼果实贮藏期间果皮褐变的发生;同时,果实采前套袋促进龙眼果实采后果肉自溶和病害发生,降低果实耐贮性,缩短龙眼果实贮藏期。综合研究结果认为,果实采前套袋能有效改善‘立冬本’龙眼果实的外观品质和营养品质,其最佳套袋时期为盛花后110 d（即果实采收前1个月左右）;但果实采前套袋降低‘立冬本’龙眼果实的耐贮性,不利于延长龙眼果实贮藏期。     

3种斜纹夜蛾性信息素诱芯诱蛾试验研究

 2011年斜纹夜蛾性信息素诱蛾试验结果表明：3种诱芯诱蛾性能均较强、持效期长、防效佳、操作简便;6－9月试验区A、B、C三种诱芯单只诱捕器日均诱蛾量分别达112头、89.6头和299.5头,分别是20 W频振式杀虫灯的15.9,12.7和42.5倍;相对防效分别为75.50%,70.25%和82.28%。     

不同植物源农药对烟青虫和斜纹夜蛾防治效果研究

为验证植物源农药(4%鱼藤酮乳油和0.3%苦参碱水剂)在烟草害虫防治上的应用效果,2015年在衡阳县、衡南县和耒阳市采用田间小区试验,研究其对烟青虫和斜纹夜蛾的防治效果。结果表明,植物源农药的防治效果比化学农药好,鱼藤酮的防治效果优于苦参碱,但差异不显著。喷施植物源农药烟株受损率降低,能有效保护害虫天敌。鱼藤酮和苦参碱对烟草烟青虫和斜纹夜蛾防效好,无残留,对人体无害,不污染环境,是未来农药发展的方向。     

非洲楝提取物对斜纹夜蛾的杀虫活性研究

室内测定了非洲楝提取物对斜纹夜蛾幼虫的杀虫活性。结果显示,非洲楝提取物对斜纹夜蛾幼虫具有很强的毒杀作用,10和14 d的LC50值分别为0.466和0.173 mg/mL;此外,非洲楝提取物对斜纹夜蛾幼虫还表现出较强的抑制生长发育作用,与对照相比,幼虫龄期和蛹期延长,蛹重减小,化蛹率和成虫羽化率显著降低。非洲楝具有防治斜纹夜蛾的潜力。     

无翅茶蚜对茶树挥发物的触角电生理和行为反应

分别使用昆虫触角电位仪（EAG）和四臂嗅觉仪，测定了无翅茶蚜（Toxoptera aurantii Boyer）对14种茶树挥发性化合物、14种挥发物中“绿叶气味”组成的混合物（GLV）、14种挥发物的混合物（ACB），以及新鲜嫩叶、芽、嫩茎、成叶和茶蚜为害嫩叶（ADYL）的EAG反应和行为反应。     

色板和茶蚜性信息素对茶园天敌草蛉的引诱效应

在秋季草蛉盛发时节,开展了芽绿、土黄、墨绿、素馨黄、果绿、橘黄、大红、桃红、湖蓝、紫色、天蓝和纯白等12种色板和7种茶蚜性信息素制剂对茶园天敌草蛉的引诱试验.结果表明,供试12种色板对草蛉的引诱力以芽绿、土黄、墨绿和素馨黄最强,纯白最差,但差异未达显著水平.在蚜虫性信息素荆芥内酯和荆芥醇按一定比例配制成7种茶蚜性信息素制剂对草蛉的诱集过程中,以荆芥内酯和荆芥醇之比为1:9时,对于中华草蛉和大草蛉的诱效最强,荆芥醇引诱效应显著.     

性诱剂和植物源引诱剂及色彩对茶蚜雄蚜诱效差异

茶蚜刺吸茶树嫩梢,致茶叶减产和品质下降,已成为许多茶区的主要害虫.秋季短日照诱导茶蚜雄蚜、雌蚜的产生,二者交尾产受精卵越冬.本研究使用分别携带3种茶蚜性诱剂、3种植物源引诱剂的素馨黄粘板,以及油菜花黄、芽绿和素馨黄粘板诱捕深秋时节的茶蚜雄蚜,以减少雌-雄交尾机会而压低越冬基数.结果表明:①性诱剂色板的诱效显著优于植物源引诱剂色板的诱效,后者诱效又优于色板的诱效;②3种性诱剂诱效之间差异显著,其中以荆芥内酯与荆芥醇1∶9比例的性诱剂的引诱力最强;③植物源引诱剂诱效之间有明显差异,以反-2-己烯醛、正戊醇、2-戊烯-1醇、正己醇、顺-3-己烯-1-醇和顺-3-己烯乙酸酯1∶1∶1∶1∶5∶25比例的引诱剂诱效最佳;④3种诱虫色板诱效之间有差异,以油菜花黄诱效最好.深秋使用携带茶蚜性诱剂(荆芥内酯:荆芥醇=1∶9)的油菜花黄粘板可有效诱捕雄蚜而压低越冬基数,有效地控制春茶至夏茶前期这段时间茶蚜的发生.     

红棕象甲成虫对5种植物发酵挥发物的行为反应

利用Y型嗅觉仪测定了红棕象甲(Rhynchophorus ferrugineus)成虫对甘蔗(Saccharum officinarum)、椰子(Cocos nucifera)、假槟榔(Archontophoehix alexandra)、槟榔(Areca catechu)和菠萝(Ananas comosus)等5种植物发酵挥发物的选择行为.结果表明,红棕象甲成虫对不同植物发酵挥发物敏感性不同,对寄主植物的选择性显著高于非寄主植物菠萝,依次排序:甘蔗≈椰子>假槟榔≈槟榔>菠萝.雌成虫和雄成虫对椰子和甘蔗的行为反应同其他3种植物相比有更强的趋性,但雄成虫对假槟榔、槟榔和菠萝3种植物发酵挥发物的选择性无显著差异.甘蔗、椰子、假槟榔3种植物食物诱饵的田间诱捕试验结果表明,植物挥发物对红棕象甲聚集信息素具有极显著的增效作用(P<0.01).3种植物田间诱捕效果差异显著(P<0.05),依次为:甘蔗>椰子>假槟榔.不同食物诱饵诱捕的雌成虫数均多于雄成虫.     

中华稻蝗对植物挥发性化学物质的触角电生理和行为反应

采用触角电位仪(EAG)和Y型嗅觉仪测定了中华稻蝗6龄若虫和成虫对9种植物挥发性化学物质的嗅觉和行为反应.EAG反应结果表明,中华稻蝗成虫对9种植物挥发性化学物质的反应值均低于6龄若虫,其中对顺-3-己烯-1-醇的EAG反应值6龄若虫显著高于成虫,对香叶醇的EAG反应6龄雌性若虫显著高于成虫及雄性若虫.1-戊醇可引发中华稻蝗雌、雄6龄若虫间显著的EAG反应差异,雌、雄成虫对9种挥发性化合物的EAG反应表现一致.行为测定结果表明,除6龄雄虫外,中华稻蝗其他各虫态对反-2-己烯醛和乙酸顺-3-己烯酯2种化合物均表现出显著的行为趋性.中华稻蝗对香叶醇的EAG反应和行为反应相一致.对水稻、稗草和马唐3种寄主植物的行为反应测定结果表明,中华稻蝗雌性成虫和雌性6龄若虫对马唐存在显著的行为趋向性,而所有试虫对水稻和稗草却表现出随机选择效应.因此,香叶醇很有可能会在中华稻蝗对寄主植物的定向行为中发挥重要作用,而对寄主植物的选择性可能会影响中华稻蝗雌虫的生长发育及产卵行为.     

茶毛虫性信息素对茶毛虫防治效果研究

在贵州湄潭茶场和平坝茶场研究了茶毛虫性信息素引诱剂大面积诱杀茶毛虫的效果,结果表明,茶毛虫性信息素引诱剂以B型效果最好,42天内两地每盆每晚平均可诱到3.41头和7.51头,最高可诱到198头,大面积使用区内茶毛虫雌蛾怀卵量比对照区减少93.50%,卵块减少85.21% ,幼虫数量减少81.15%,说明茶毛虫性信息素引诱剂诱蛾效果非常明显。     

黄蝉花素抑制斜纹夜蛾生长发育作用

室内测定了黄蝉花素对斜纹夜蛾幼虫的抑制生长发育活性。结果表明,黄蝉花素对斜纹夜蛾幼虫的抑制生长发育活性与其处理浓度具有一定的相关性。与对照相比,处理组食物消耗量减少,幼虫生长发育被抑制,发育历期延长。处理组幼虫在蛹期不能正常化蛹而形成畸形蛹,羽化后的成虫表现为形态畸形。在预蛹期和蛹期由于不能正常蜕皮导致死亡率较高。研究显示黄蝉花素作为一类新型的昆虫生长发育控制剂或害虫田间种群管理的先导化合物值得进一步研究。     

Resistance of Spodoptera litura (Lepidoptera: Noctuidae) to profenofos: Relative fitness and cross resistance

Profenofos, an acetylcholine esterase inhibitor insecticide, has been used for the management of various lepidopteron pests of many crops in Pakistan. In the present study, we investigated the impact of insecticide resistance on fitness cost in Spodoptera litura, and evaluated cross resistance to other insecticides. The effect of profenofos on different life history parameters including survival rate, female ratio, fecundity and hatchability, intrinsic rate of population increase and biotic potential was determined. Significant differences associated with fitness costs were revealed. A field collected S. litura strain was selected by exposure to profenofos in the laboratory (Profen-SEL) and after 14 generations of selection it developed a 52-fold resistance to this insecticide. The Profen-SEL strain showed high cross-resistance to chlorpyrifos (62-fold), but very low to no cross resistance to lambda-cyhalothrin (2.34-fold) or methomyl (0.80-fold), respectively. The resistant strain had a relative fitness of 0.38 with a low larval survival rate, longer larval duration, longer male pupal duration, longer development time, low emergence rate of healthy adults, fecundity and hatchability compared with an unselected strain. The intrinsic rate of natural population increase, mean relative growth rate and biotic potential were lower for the selected strain compared with an unselected strain. Development of resistance may cause fitness costs for the resistant strain. This study provided important information for understanding profenofos resistance and facilitating a better strategy for the management of resistance.     

Effect of Pheromone Blend Components,Sex Ratio,and Population Size on the Mating of Cadra cautella (Lepidoptera: Pyralidae)

The almond moth Cadra cautella (Walker), a key pest of storage facilities, is difficult to manage using synthetic chemicals. Pheromone-based management methods remain a high priority due to advantages over conventional management practices, which typically use insecticides. Cadra cautella females release a blend of pheromone including (Z, E)-9,12-tetradecadienyl acetate (ZETA) and (Z)-9-tetradecadien-1-yl acetate (ZTA). The effect of these components on mating of C. cautella and how response varies with the population density and sex ratio remain unknown. In this study, the mating status of C. cautella was studied inside mating cages under different ratios of ZETA and ZTA diluted in hexane and at different population sizes either with equal or unequal sex ratio. The lowest percentage of mated females (highest mating disruption [MD] effects), corresponding to roughly 12.5%, was produced by a 5:1 and 3.3:1 ratio of ZETA:ZTA. Populations with equal sex ratio showed the lowest percentage of mated females, at 20% and 12.5% under lower and higher density, respectively. The next lowest percentage of mated females was produced when the sex ratio was set to 1: 2 and 2:1 male:female, with just 25% and 22.5% of moths mated, respectively. This study shows that mating status of C. cautella is influenced by ZETA:ZTA ratio, sex ratio, and population size. This current knowledge would have useful implications for mating disruption programs.     

Helicoverpa zea (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) Responses to Sorghum bicolor (Poales: Poaceae) Tissues From Lowered Lignin Lines

The presence of lignin within biomass impedes the production of liquid fuels. Plants with altered lignin content and composition are more amenable to lignocellulosic conversion to ethanol and other biofuels but may be more susceptible to insect damage where lignin is an important resistance factor. However, reduced lignin lines of switchgrasses still retained insect resistance in prior studies. Therefore, we hypothesized that sorghum lines with lowered lignin content will also retain insect resistance. Sorghum excised leaves and stalk pith Sorghum bicolor (L.) Moench (Poales: Poaceae) from near isogenic brown midrib (bmr) 6 and 12 mutants lines, which have lowered lignin content and increased lignocellulosic ethanol conversion efficiency, were examined for insect resistance relative to wild-type (normal BTx623). Greenhouse and growth chamber grown plant tissues were fed to first-instar larvae of corn earworms, Helicoverpa zea (Boddie) and fall armyworms Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), two sorghum major pests. Younger bmr leaves had significantly greater feeding damage in some assays than wild-type leaves, but older bmr6 leaves generally had significantly less damage than wild-type leaves. Caterpillars feeding on the bmr6 leaves often weighed significantly less than those feeding on wild-type leaves, especially in the S. frugiperda assays. Larvae fed the pith from bmr stalks had significantly higher mortality compared with those larvae fed on wild-type pith, which suggested that bmr pith was more toxic. Thus, reducing lignin content or changing subunit composition of bioenergy grasses does not necessarily increase their susceptibility to insects and may result in increased resistance, which would contribute to sustainable production.     

Identification and Characterization of Aldehyde Oxidase 5 in the Pheromone Gland of the Silkworm (Lepidoptera: Bombycidae)

Aldehyde oxidases (AOXs) are a subfamily of cytosolic molybdo-flavoenzymes that play critical roles in the detoxification and degradation of chemicals. Active AOXs, such as AOX1 and AOX2, have been identified and functionally analyzed in insect antennae but are rarely reported in other tissues. This is the first study to isolate and characterize the cDNA that encodes aldehyde oxidase 5 (BmAOX5) in the pheromone gland (PG) of the silkworm, Bombyx mori. The size of BmAOX5 cDNA is 3,741 nucleotides and includes an open reading frame, which encodes a protein of 1,246 amino acid residues. The theoretical molecular weight and isoelectric point of BmAOX5 are approximately 138 kDa and 5.58, respectively. BmAOX5 shares a similar primary structure with BmAOX1 and BmAOX2, containing two [2Fe-2S] redox centers, a FAD-binding domain, and a molybdenum cofactor (MoCo)-binding domain. RT–PCR revealed BmAOX5 to be particularly highly expressed in the PG (including ovipositor) of the female silkworm moth, and the expression was further confirmed by in situ hybridization, AOX activity staining, and anti-BmAOX5 western blotting. Further, BmAOX5 was shown to metabolize aromatic aldehydes, such as benzaldehyde, salicylaldehyde, and vanillic aldehyde, and fatty aldehydes, such as heptaldehyde and propionaldehyde. The maximum reaction rate (V_max) of benzaldehyde as substrate was 21 mU and K_m was 1.745 mmol/liter. These results suggested that BmAOX5 in the PG could metabolize aldehydes in the cytoplasm for detoxification or participate in the degradation of aldehyde pheromone substances and odorant compounds to identify mating partners and locate suitable spawning sites.     

Disruption of Darna pallivitta (Lepidoptera: Limacodidae) by Conventional and Mobile Pheromone Deployment

Identification of the Darna pallivitta (Moore) pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOn-Bu) has made it possible to investigate communication disruption to control this lepidopteran pest. Conventional communication disruption trials showed marked decreases in the mean number of male moths captured in E7,9-10:COOnBu-treated fields compared with control fields. For traps baited with E7,9-10:COOnBu, percent disruptions were 94.4% and 92.1% for septa (1 g pheromone/ha, 1-wk trial duration) and spirals (6 g pheromone/ha, 8-wk trial duration) respectively. For traps baited with virgin female moths, percent disruption was 73.3% using septa disruptors (1 g pheromone/ha, 1-wk trial duration). Mobile communication disruption using Bactrocera cucurbitae (Coquillett) as carriers for E7,9-10:COOn-Bu was evaluated in the following three areas: fly survivorship, attraction of male moths to treated flies, and moth disruption in a small-scale field trial. Topical application of E7,9-10:COOnBu showed no significant decrease in survivorship at 50 and 80 µg/fly. However, decreased survivorship was observed at 100 µg/fly and linear regression showed E7,9-10:COOnBu dose was significantly correlated with B. cucurbitae survivorship. Traps containing honey–pheromone-fed flies attracted and caught D. pallivitta over a 1-wk period, demonstrating the attractiveness of the carrier. Releasing E7,9-10:COOnBu-fed B. cucurbitae (∼2 g pheromone/ha, 1-wk trial duration) resulted in significantly reduced trap catches in treatment fields compared with control fields on the first 2 d of the field trial. Percent disruptions were 84.7% (day 1) and 56.0% (day 2). These results suggest that both conventional communication disruption and mobile communication disruption have potential to control D. pallivitta.