豚草卷蛾和苍耳螟对豚草的联合控制作用

豚草卷蛾Epiblema strenuana是我国引进用于控制豚草Ambrosia artemisiifolia的重要天敌昆虫,苍耳螟Ostrinia orientalis是取食苍耳和豚草的本地种。为了全面评价释放的豚草卷蛾与苍耳螟共存系统中的竞争与控制作用, 作者采用三因子二次正交旋转组合设计的方法,选用豚草的生育期（以主茎近基部直径表示）、豚草卷蛾和苍耳螟虫量为参试因子,分别以豚草的地上部生物量（鲜重）、种子量和株高作为观测目标,分析了豚草卷蛾和苍耳螟对豚草的综合控制效应。结果表明,两种天敌对寄主的生物量、种子量和株高均有明显的抑制作用。各处理组合中,具有最大控制效果的处理组合及其防效分别为：当主茎直径为1.0 cm,单株分别接入豚草卷蛾和苍耳螟63头和8头时,对生物量的控制效果达到94.3%;当主茎直径为1.0 cm,分别接入豚草卷蛾和苍耳螟17头和8头时,对株高的防效为31.7%;当接虫主茎直径为0.7 cm时,单株分别接入豚草卷蛾和苍耳螟40头和5头时,对种子量的防效达到99.3%。而当主茎直径达到2.1cm时,分别接入豚草卷蛾和苍耳螟40头和5头,两种天敌对寄主生物量、种子量和株高的防效仅分别为2.0%、6.1%和-2.4%,抑制效果最低。两种天敌的控制效果随寄主生长和补偿能力的增强而减弱。当寄主处于生长前期（主茎直径小于0.7 cm）时,两种虫量的作用效应大于植株的补偿作用;而长成的寄主植物其补偿效应则大于两种天敌的虫量作用。3种因子间的作用方式相互独立,两种天敌之间不存在明显的竞争干扰现象,属于可利用的有效天敌。综合平均效应表明,寄主的生育期（补偿能力）要大于两种虫量的影响,豚草卷蛾对寄主种子量的影响大于苍耳螟,而苍耳螟对寄主的生物量和植株高度的影响要大于豚草卷蛾。在两种天敌的应用中,为了提高防治效果建议及早在豚草的生长前期释放或扩增天敌种群数量。     

豚草卷蛾寄主专一性风险评价

在以往豚草生物防治研究的基础上 ,为评价防治恶性豚草的外来天敌昆虫的安全性 ,以及探索外来生防作用物的风险评价方法 ,以豚草卷蛾为案例 ,进一步对其寄主安全性进行了风险评估。基于与豚草的近缘关系及以往的研究结果 ,选用 9科 36种常见经济作物、观赏植物和杂草 ,采用室内非选择性取食测定、田间开放条件下多选择性取食测定和室外非选择性取食分龄接虫的生命表等研究方法 ,对豚草卷蛾的寄主专一性作了深入研究。 ( 1 )室内非选择性取食测定结果表明 ,豚草卷蛾仅能在豚草和苍耳上完成整个幼虫的发育 ;但在强迫将高龄幼虫 ( 4～ 6龄 )接入黄花蒿、菊花 (黄莲 )和向日葵 (白 97-1和天委 F2 )时 ,有少量幼虫能发育化蛹 ,但不发生取食 ,在这些植物上完成发育只是一种假象。 ( 2 )田间开放条件下多选择性取食测定结果表明 ,豚草卷蛾的寄主选择性随种群数量不同而异 ,当种群数量增大 ,受取食条件胁迫时 ,出现风险“扩散”现象。田间供试的 1 6种 (含品种 )植物中 ,第 2、3和 4代出现虫瘿 (被幼虫选择 )的供试植物依次为 :豚草(第 2代 ) ;豚草和苍耳 (第 3代 ) ;豚草、苍耳和黄花蒿 (第 4代 )。按产卵单因子选择性风险指数 ( SEFRI(1) )值分析表明 ,豚草卷蛾成虫产卵对豚草、苍耳和黄花蒿表现出选择性风险     

豚草卷蛾的生态适应性及其风险评价

豚草卷蛾是害草豚草和银胶菊的重要天敌．本文就该虫生态适应性、对目标杂草的控制效能、引进与释放的安全性评价作了综述．豚草卷蛾具有严格的寄主专一性,所有田问选择性寄主均局限于豚草亚族,而对向日葵和菊花仅表现为随机风险(风险值<0．01)或0风险;生态适应性强。适宜发育的温度为15～35℃,越冬虫态的低温下限为-8～-12℃;种群增长快．能在豚草和苍耳上分别以23和4倍的速度增长;控制能力强,大量感染时田间寄主的平均虫瘿达到每株20～30头,营养生长前期5．2虫瘿可使植株死亡,营养生长后期26个虫瘿可使植株致死,释放后12个月内扩散区域超过100km;对释放地天敌苍耳螟不构成竞争,是控制豚草和银胶菊的有效天敌,可以安全应用．     

寄主植物对亚洲玉米螟生长发育及雄蛾保护酶活性的影响

【目的】为了明确不同寄主植物对亚洲玉米螟Ostrinia furnacalis (Guenée)生长发育、繁殖及雄蛾保护酶活性的影响。【方法】在温度为(25±5)℃、湿度为75%±5%、光照周期为L∶D=16∶8的恒定条件下,研究了7科12种寄主植物对亚洲玉米螟发育历期、蛹期、成虫期、羽化率、雌蛾繁殖力及雄蛾体内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活力的影响。【结果】亚洲玉米螟能够在12种寄主植物上完成生长发育。取食苍耳的幼虫历期较短(17.4 d),蛹期较短(5.9 d);成虫寿命较长(9.0 d),蛹重较大(50.7 mg);取食油菜的幼虫单雌产卵量较大(210粒/雌),取食油菜和油麦菜的幼虫成活率和蛹羽化率较高,均在80.0%以上。幼虫取食不同植物后,雄蛾体内保护酶的活性差异显著,幼虫取食酸模叶蓼后,雄蛾体内SOD活性较高,幼虫取食苍耳后,雄蛾体内POD和CAT活性较高。【结论】不同寄主植物对亚洲玉米螟生长发育、繁殖及雄蛾保护酶活性均有显著影响。取食苍耳和酸模叶蓼有利于亚洲玉米螟的生长发育。玉米螟在不同寄主植物上的生长发育和繁殖与保护酶活性呈现正相关性。亚洲玉米螟在取食不同寄主植物时,能调节自身保护酶的活性,来适应寄主,满足生长发育的需要。     

永州广聚萤叶甲和豚草卷蛾的种群动态及对豚草的控制效果

【目的】豚草是一种重要的入侵杂草,严重危害农业生产和人类健康。广聚萤叶甲和豚草卷蛾是豚草的专一性天敌。研究这2种天敌在永州的种群动态及其对豚草的控制效果,可以为永州豚草的防控及这2种天敌的有效利用提供依据。【方法】在湖南省永州市江永县豚草大面积发生区域,人工释放广聚萤叶甲和豚草卷蛾,调查这2种天敌在释放区和扩散区的种群动态和对豚草的防治效果,以及这2种天敌在扩散区的越冬情况。【结果】广聚萤叶甲和豚草卷蛾的扩散能力强。释放1个月后,在释放区,广聚萤叶甲各虫态及豚草卷蛾虫瘿均被发现。整体上,随时间延长,广聚萤叶甲各虫态虫口密度先增后减,而豚草卷蛾虫瘿密度呈逐渐降低趋势。释放2个月后,在距释放区边缘10 km的豚草发生区,发现了广聚萤叶甲和豚草卷蛾,且成功建立了种群并顺利越冬。释放区豚草株高几乎没有增加,且叶片最终被取食精光,几乎全部死亡;扩散区豚草株高略有增加,最终近75%叶片被取食。【结论】广聚萤叶甲和豚草卷蛾可在永州成功建立种群并安全越冬,还能自行扩散,可持续控制野外豚草的发生。     

豚草和苍耳上广聚萤叶甲的寄主选择和取食量比较

为探究豚草与苍耳上的广聚萤叶甲种群是否存在分化,对来自这两种植物上的叶甲(分别称为"豚草叶甲"和"苍耳叶甲")进行了选择性试验,并测定了其对5种近缘植物的取食量.选择性试验结果表明,两群来源不同的叶甲对豚草和苍耳的选择偏好存在显著差异,表现为豚草叶甲更偏好豚草,而苍耳叶甲相对更偏好苍耳.对广聚萤叶甲成虫取食量的测定结果表明,对不同测试植物的取食量随来源寄主植物不同而存在显著差异,两群叶甲对向日葵的取食量存在显著差异,但对其他植物的取食量均无显著差异.豚草叶甲对豚草的取食量显著大干对其他测试植物的取食,24h平均取食量达51.27 mm2,而对其他4种植物的取食量无显著差异,均低于40 m2;苍耳叶甲取食豚草的量为52.24mm2(24 h),与取食向日葵和三裂叶豚草量无显著差异,但显著大干取食苍耳和菊芋的量,取食后两种植物的量没有显著差异.研究结果说明,苍耳属植物可能是广聚萤叶甲除豚草外的另一潜在寄主植物.     

封面照片

正照片示在寄主植物面包果Artocarpus altilis(桑科)上的黄翅绢野螟Diaphania caesalis(鳞翅目:螟蛾科)高龄幼虫。该虫幼期钻蛀取食危害菠萝蜜A. heterophyllus、榴莲蜜A. champeden、面包果A. altilis等菠萝蜜属Artocarpus多种热带经济作物。本期报道了黄翅绢野螟生物学特性及田间种群动态研究(pp. 63-72)。照片由王     

蟒河猕猴国家级自然保护区蛾类群落生态位特征

为了解山西蟒河猕猴国家级自然保护区蛾类群落与环境资源的相互关系,采用Levins生态位宽度和Pianka生态位重叠指数对山西蟒河猕猴国家级自然保护区蛾类群落结构和生态位进行分析。结果表明:在本保护区内采集蛾类标本隶属24科,其中螟蛾科、夜蛾科、卷蛾科和尺蛾科为优势类群;该保护区内主要蛾类的时间生态位宽度高于空间生态位宽度,各类群间存在程度不同的生态位重叠现象,其中尺蛾科和螟蛾科的时间生态位重叠指数(0.913)和空间生态位重叠指数(0.852)均高于其他类群;天蛾科和舟蛾科时间生态位重叠指数(0.772)也较高,但其空间生态位重叠指数(0.218)却较低;除天蛾科与毒蛾科时间生态位相似性系数(0.247)、天蛾科与大蚕蛾科(0.258)和舟蛾科与天蛾科(0.226)空间生态位相似性系数较小外,大多蛾类类群间生态位相似性系数均较大。说明蟒河猕猴国家级自然保护区主要蛾类群落之间生态位竞争较激烈。     

BT基因棉与常规棉主要害虫及天敌生态位的比较研究

本研究了BT基因棉与常规棉主要害虫及天敌的生态位。结果表明：主要害虫及天敌的种类一致,但棉铃虫幼虫的数量差异显;33B棉田各昆虫种群的生态位宽度指数偏高;棉铃虫、棉蚜对主要天敌的生态位重叠指数偏高。应用生态位概念分析了造成区别的原因。     

漯河地区农田灯下蛾类群落结构和优势蛾生态位分析

为明确农田生境灯下蛾类群落结构和优势蛾的生态位特点,2017-2021年在漯河市郊区农田利用虫情测报灯对蛾类进行了逐日监测分析。结果表明,5年共诱集蛾类昆虫11科121种150 861头,统计得到个体数量（N)、物种丰富度(S)、群落多样性指数(H)、相似性系数(Cs)、生态位宽度（Bi）和生态位重叠(Cij)等相关群落数据参数。3-11月农田灯下蛾类个体数量、物种丰富度和群落多样性指数,均随时间呈先增加后减小的趋势;不同月份间的群落相似性指数差异较大。年度优势蛾为东方黏虫M. separata、棉铃虫Helicoverpa armigera和甜菜夜蛾Spodoptera exigua 3种。月度优势蛾共9种,其中亚洲玉米螟Ostrinia furnacalis和棉铃虫的生态位宽度最大0.4434和0.4002,东方黏虫最小（0.1811）;棉铃虫和甜菜叶螟Hymenia recurvalis与其余8种优势蛾的生态位重叠指数均较大,而东方黏虫和其余优势蛾的生态位重叠指数均较小。研究结果为开展蛾类监测预警和有效防治提供参考数据。     

Trichogramma bournieri Pintureau & Babault (Hymenoptera: Trichogrammatidae) and Chilo sacchariphagus Bojer (Lepidoptera: Crambidae) in sugarcane in Mozambique: A new association

Chilo sacchariphagus Bojer (Lepidoptera: Crambidae), a sugarcane stalk borer indigenous to South East Asia, and the nearby Indonesian Islands, was identified from African sugarcane in Mozambique in 1999. Prior to a classical biocontrol programme being implemented against it, intensive pre-release surveys for the presence of any indigenous natural enemies on life stages of the borer were completed. Negligible parasitism of larval and pupal stages was recorded. In contrast, egg batches found were heavily parasitised. Parasitoid adults emerging from the eggs were found to be only the indigenous Trichogramma bournieri Pintureau & Babault (Hymenoptera: Trichogrammatidae). Aspects of the impact of T. bournieri on C. sacchariphagus eggs in Mozambican sugarcane are presented, and the potential of using this egg parasitoid against C. sacchariphagus in an augmentation biocontrol programme is discussed.     

Stem borer infestation of cereal crops in Jere,the Sudan-Sahelian savanna region of Nigeria

Field data collected during the rainy season of two years, 2010 and 2011, were used to determine the per cent plant infestation and stem borer abundance on cultivated cereal crops grown by farmers' in Jere or the Sudan-Sahelian savanna ecological region of Nigeria. Stem borers were recovered using destructive sampling. Mean total per cent plant infestation and stem borer abundance per farmers' field were significantly higher on millet (40% and 25 individuals, respectively) and sorghum (30% and 21 individuals, respectively) than on maize (19% and 13 individuals, respectively). Of the five stem borer species found in this study, Coniesta ignefusalis (Lepidoptera: Pyralidae) (3.5)/Chilo sp. nr. aleniellus (Lepidoptera: Crambidae) (2), Busseola fusca (Lepidoptera: Noctuidae) (3.1)/Sesamia calamistis (Lepidoptera: Noctuidae) (2.4) and S. calamistis (2.9), with significantly higher number of individuals per plant, tended to be more important pests on millet, sorghum and maize crops, respectively. Although, mean total per cent plant infestation and abundance of stem borers in this study were generally moderate, further studies on the effects of different types of cereals intercropping (locally practiced) on stem borer infestation and abundance should ascertain the true importance of these pest species in the Sudan-Sahelian savanna ecological region of Nigeria.     

Constraints on the use of Trichogramma Egg Parasitoids in Biological Control Programmes in India

The use of Trichogramma (Hymenoptera: Trichogrammatidae) egg parasitoids for the biological control of several insect pests, including the pod borer Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), is being promoted in India. Several companies supply these parasitoids to farmers, but no evaluation of product quality has been made. Low product quality is recognized as being one of the most important reasons for the failure of these biocontrol agents. In this study, Trichogramma chilonis Ishii egg-cards were obtained from eight producers in southern India. Product quality was evaluated using the following parameters: number of eggs/card, percentage parasitism, percentage emergence, progeny sex ratio and percentage of deformed females. In addition, producers were asked for the average values of these parameters in their production systems and for their recommendations for the use of T. chilonis to control H. armigera in cotton. The quality of the egg-cards was highly variable and was much lower than that stated by the producers. The recommended frequency and interval of releases, and the number of parasitoids to be released, differed greatly among producers. The low product quality results in up to 85% fewer parasitoids being released than is recommended by the producer. The effect of the low product quality and the highly variable release recommendations on applied biological control programmes is discussed. Suggestions for more effective use of Trichogramma spp. are given.     

Susceptibility of the peachtree borer, Synanthedon exitiosa, to Steinernema carpocapsae and Steinernema riobrave in laboratory and field trials

The nematode Steinernema carpocapsae (All) strain was significantly more effective against peachtree borer larvae (Synanthedon exitiosa [Lepidoptera: Sesiidae]) than Steinernema riobrave (7-12) strain in field and laboratory experiments. Eighty-eight percent control of peachtree borer larvae was obtained with S. carpocapsae in the field trial when applied at 3 x 10(5) infective juveniles per tree, and 92% mortality was obtained in the lab assay using 50 infective juveniles per larva.     

The role of intercrops of eggplant and cowpea on the control of Leucinodes orbonalis guenee (Lepidoptera: Crambidae)

BioControl - The eggplant fruit and shoot borer (EFSB), Leucinodes orbonalis Guenee (Lepidoptera: Crambidae) is the major pest of eggplant, Solanum melongena L., in Iran. Influences of...     

Examination of sex attractants for monitoring weed biological control agents in Hawaii

The identification of sex attractants was undertaken for potential use in the study of two biological control agents against Rubus spp. in Hawaii. Attractants for Croesia zimmermani (Lepidoptera: Tortricidae) and Schreckensteinia festaliella (Lepidoptera: Heliodinidae) were developed by field screening a variety of putative lures in sticky traps, based on attractants for congeneric species. Croesia zimmermani was most attracted to E11-tetradecen-1-ol and E11-tetradecenal, while S. festaliella was attracted to (10,12)-(E,E)-hexadecadienal alone. Development of monitoring systems based on sex attractants can enable better evaluation of biocontrol programmes, and provide cost-effective information on presence/absence, density, phenology, synchrony with the host, dispersal rate and other useful parameters.     

Genetic basis of resistance to fall armyworm (Lepidoptera: Noctuidae) and southwestern corn borer (Lepidoptera: Crambidae) leaf-feeding damage in maize

Leaf-feeding damage by first generation larvae of fall armyworm, Spodopter frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), and southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae), cause major economic losses each year in maize, Zea mays L. A previous study identified quantitative trait loci (QTL) contributing to reduced leaf-feeding damage by these insects in the maize line Mp704. This study was initiated to identify QTL and their interactions associated with first generation leaf-feeding damage by fall armyworm and southwestern corn borer. QTL associated with fall armyworm and southwestern corn borer resistance in resistant line Mp708 were identified and compared with Mp704. Multiple trait analysis (MTA) of both data sets was then used to identify the most important genetic regions affecting resistance to fall armyworm and southwestern corn borer leaf-feeding damage. Genetic models containing four and seven QTL explained southwestern corn borer and fall armyworm resistance, respectively, in Mp708. Key genomic regions on chromosomes 1, 5, 7, and 9 were identified by MTA in Mp704 and Mp708 that confer resistance to both fall armyworm and southwestern corn borer. QTL regions on chromosomes 1, 5, 7, and 9 contained resistance to both insects and were present in both resistant lines. These regions correspond with previously identified QTL related to resistance to other lepidopteran insects, suggesting that broad-spectrum resistance to leaf feeding is primarily controlled by only a few genetic regions in this germplasm.     

Life table studies of Elasmopalpus lignosellus (Lepidoptera: Pyralidae) on sugarcane

The lesser cornstalk borer, Elasmopalpus lignosellus (Zeller) (Lepidoptera: Pyralidae) is an important pest of sugarcane (a complex hybrid of Saccharum spp.) in southern Florida. Reproductive and life table parameters for E. lignosellus were examined at nine constant temperatures from 13 to 36 °C with sugarcane as the larval food source. The pre- and postoviposition periods decreased with increasing temperatures and reached their minimums at 33 and 36 °C, respectively. The oviposition period was longest at 27 °C. The mean fecundity, stage-specific survival, stage-specific fecundity, intrinsic rate of increase, and finite rate of increase were greatest at 30 °C and decreased with increasing or decreasing temperature. The net reproductive rate was greatest at 27 °C. The Logan-6 model best described the relationship between temperature and intrinsic rate of increase. The generation and population doubling times were longest at 13 and shortest at 33 and 30 °C, respectively. The most favorable temperatures for E. lignosellus population growth were between 27 and 33°C. Life table parameters for E. lignosellus reared on sugarcane were greater than for the Mexican rice borer [Eoreuma loftini (Dyar) (Lepidoptera: Crambidae)] reared on an artificial diet at 30 °C. The intrinsic rates of increase for the sugarcane borer [Diatraea saccharalis (F.) (Lepidoptera: Crambidae)] reared on sugarcane or corn were the same as for E. lignosellus reared on sugarcane at 27 °C, but the net reproductive rate was four times higher for the former than the latter borer species.     

Population genetics of Eldana saccharina Walker (Lepidoptera: Pyralidae) and the implications for management using biocontrol

The African sugarcane stalk borer, Eldona saccharina Walker (Lepidoptera: Pyralidae), is widely distributed throughout sub-Saharan Africa and is an important insect pest of maize and sugarcane. The insect shows significant variation in behaviour, host plant and natural enemy guild in different regions. Several attempts to redistribute the natural enemies of E. saccharina from West Africa to South Africa were unsuccessful. The significant behavioural, host plant and natural enemy variations as well as failures of biocontrol attempts evoked a hypothesis of genetic diversification. To evaluate this hypothesis a molecular analysis was conducted on geographically isolated populations of E. saccharina from East, North, South and West Africa, using the cytochrome c oxidase subunit I (COI) region of the mitochondrial genome. The results revealed that E. saccharina populations are separated into four major units corresponding to the West Africa, Rift Valley, South/East Africa and southern African populations. Mitochondrial DNA divergence among the four populations ranged from 1% to 4.98%. To examine the impact of the observed genetic variation on the fertility of inter-population crosses, a mating experiment was conducted between the Rift valley and South African population to produce an F1 generation, and these were backcrossed with the South African parent population. Fertility of eggs produced by the F1/parent population cross was significantly reduced when compared to fertility of the "true" South African line, and the F1/F1 cross. The contributions of the observed genetic differences and inter population incompatibility for the failure of previous biocontrol attempts are discussed and recommendations on future biocontrol practices are given.     

Infiltration by alien predators into invertebrate food webs in Hawaii: a molecular approach

Abstract Alien invertebrate predators have been introduced to Hawaii to control pests, particularly in lowland areas where most crops are grown. We developed techniques for assessing the impact of these predators on native food webs in relatively pristine upland areas where, it was hypothesized, few lowland predators might be found. Predator densities were assessed along transects within the Alakaii Swamp on Kaua'i. The most numerous alien biocontrol agents found were Halmus chalybeus (Coccinellidae), a species known to feed on Lepidoptera eggs. Laboratory experiments were conducted using two genera of endemic Lepidoptera, Scotorythra and Eupithecia (Geometridae), that are of considerable conservation value, the former because of its recent speciation across Hawaii, the latter for its unique predatory larvae. Techniques were developed for detecting Lepidoptera DNA within the guts of alien predators using prey-specific PCR primers. General primers amplified fragments of the mitochondrial cytochrome oxidase I gene from beetles and Lepidoptera. The sequences were aligned and used successfully to design target-specific primers for general detection of the remains of Geometridae and for particular species, including Scotorythra rara and Eupithecia monticolans. DNA fragments amplified were short [140-170 base pairs (bp)], optimizing detection periods following prey ingestion. Trials using the introduced biocontrol agent Curinus coeruleus (Coccinellidae) demonstrated detection of Lepidoptera DNA fragments = 151 bp in 85-100% of beetles after 24 h digestion of an early instar larva. This study provides a framework for future use of molecular gut analysis in arthropod conservation ecology and food web research with considerable potential for quantifying threats to endemic species in Hawaii and elsewhere.