An immunological method for granulovirus detection in larvae of Tuta absoluta: searching for isolates with prospects for biological control of this pest in Colombia

The tomato leafminer Tuta absoluta is an important insect pest of tomato crops worldwide. Biological control using entomopathogenic viruses such as isolates of Phthorimaea operculella granulovirus (PhopGV) can be a promising tool for suitably controlling this pest. However to date, few viral isolates from T. absoluta have been reported. Therefore, the aim of this study was to develop an economic, fast and accurate immunological technique for granulovirus detection and to evaluate viral presence in T. absoluta larvae from field samples collected in Colombia. Polyclonal antibodies against PhopGV were produced by using hens and rabbits. The production system in hen was selected as the most efficient and simple method. Then, a dot-blot test was developed, demonstrating the ability of antibodies to recognize granulovirus. Finally, granulovirus presence in 1186 T. absoluta larvae collected in the most important tomato production areas in Colombia was evaluated, and eight isolates were found in Boyacá and Cundinamarca (0.7% of occurrence). These results constitute the first report of a granulovirus isolated from T. absoluta larvae which had been naturally infected in Colombia's tomato producing-fields, and thereby validates the use of the immunological technique to detect granulovirus in field conditions.     

短管赤眼蜂和夜蛾黑卵蜂防治草地贪夜蛾田间竞争的初步评价

短管赤眼蜂Trichogramma pretiosum与夜蛾黑卵蜂Telenomus remus均为草地贪夜蛾Spodoptera frugiperda卵期的重要寄生性天敌。为检验两种卵寄生蜂混合释放条件下的竞争能力,本试验于田间同时释放短管赤眼蜂和夜蛾黑卵蜂,统计分析了两种卵寄生蜂对草地贪夜蛾的寄生效能及种间竞争情况。结果显示,短管赤眼蜂对释放的草地贪夜蛾卵块的卵块寄生率为52.94%,卵粒寄生率为3.28%;对田间自然卵块的卵块寄生率为53.33%,卵粒寄生率为5.80%。夜蛾黑卵蜂对释放的草地贪夜蛾卵块的卵块寄生率为88.23%,卵粒寄生率为9.96%;对田间自然卵块的卵块寄生率为100.00%,卵粒寄生率为50.33%。在未进行放蜂处理的对照田中,未出现短管赤眼蜂,夜蛾黑卵蜂的卵块寄生率为23.57%,卵粒寄生率为7.67%。本研究结果表明,在高温高湿环境中,夜蛾黑卵蜂在田间竞争中处于优势。本研究结果将为利用卵寄生蜂防控草地贪夜蛾提供参考。     

Effect of growth medium, Striga seed burial distance and depth on efficacy of Fusarium isolates to control Striga hermonthica in Burkina Faso

Striga hermonthica is a destructive parasite of cereal crops in the semi‐arid tropical zone. Two greenhouse experiments were conducted at Kamboinsé, Burkina Faso, to investigate the effect of inoculum substrate and location of Striga seeds on the ability of 14 indigenous Fusarium isolates to control the parasite. In Expt 1, Fusarium isolates reduced emerged Striga number, Striga vigour and dry biomass. As a result, sorghum dry biomass and grain yield were enhanced. Inoculum substrate did not influence the ability of Fusarium isolates to control Striga. In Expt 2, Fusarium isolates, substrate and their interaction significantly influenced germination of Striga seeds at both 35 and 50 days after sowing. Isolates grown on compost were more effective at reducing germination of Striga seeds than those grown on chopped sorghum straw. The per cent germination of seeds 50 days after sowing, buried at 5 cm depth, was significantly lower than that of seeds buried at 10 cm. At 10 cm depth, Fusarium isolates still reduced Striga seed germination with respect to the control; horizontal planting distance, 5 or 10 cm from sorghum hills, had no effect.     

基于生物防治的西花蓟马治理及思考

西花蓟马Frankliniella occidentalis(Pergande)是世界性的大害虫,对温室中蔬菜花卉造成巨大的危害。20世纪70年代后在世界范围内广泛而迅速地传播蔓延,近年入侵中国。西花蓟马对农药产生了广泛的抗性,使得生物防治一直作为其综合治理中的主导措施。本文综述了世界上西花蓟马生物防治的现状,以期为中国西花蓟马的治理提供一定的借鉴作用。     

夜蛾黑卵蜂对草地贪夜蛾田间防效的初步评价

夜蛾黑卵蜂Telenomus remus是草地贪夜蛾Spodoptera frugiperda卵期的重要专性寄生蜂。本研究通过人工释放夜蛾黑卵蜂,利用释放回捕法于田间初步评价了夜蛾黑卵蜂对草地贪夜蛾卵的田间防效。结果显示,夜蛾黑卵蜂在田间对草地贪夜蛾卵块的寄生率达到100%,卵粒寄生率为84.39%,田间校正寄生率达83.54%。尽管试验全过程伴随有连续阴雨天气,但降雨对夜蛾黑卵蜂的田间防效未产生较大的负面影响。本研究是我国首例于田间应用夜蛾黑卵蜂防控草地贪夜蛾卵的报道,研究结果将为利用夜蛾黑卵蜂防控草地贪夜蛾提供重要参考。     

氯氟吡啶酯对稻田杂草的室内除草活性及田间药效评价

氯氟吡啶酯是美国陶氏益农公司最新研制开发的芳基吡啶甲酸酯类除草剂.为了明确其在水稻田的应用技术,采用温室盆栽法测定了氯氟吡啶酯对稻田主要杂草的防效以及对8个水稻品种的安全性,同时开展了田间药效评价试验.温室测定结果表明,氯氟吡啶酯对鸭舌草、鳢肠、耳基水苋、碎米莎草、异型莎草和稗均有较好的除草活性,对千金子的除草活性相对...     

The pathogenicity of Vairimorpha necatrix (Microspora: Microsporidia) against the tomato moth, Lacanobia oleracea (Lepidoptera: Noctuidae) and its potential use for the control of lepidopteran glasshouse pests

A droplet feeding technique was used to feed known amounts of Vairimorpha necatrix (Kramer) spores to larvae of the tomato moth, Lacanobia oleracea (L) in order to assess the susceptibility of this lepidopteran pest to the pathogen. All first- to fourth-instar larvae died as a result of ingesting 1000 or more V necatrix spores. Two forms of death were observed, which were dependent on the dose and the age of the insect when treated. For first-instar larvae, rapid death (within 6days of dosing) occurred after ingestion of 2000 spores, whereas lower doses resulted in a proportion of larvae dying from chronic infection (microsporidiosis). For more advanced stages, increasing spore doses were required to give rapid death, such that a dose of 200,000 spores was needed to give 80% mortality within 6 days for third-instar larvae. Rapid death was not observed in fourth- to sixth-instar larvae. In all cases successful pupation and adult emergence were much reduced compared with non-infected larvae. Suspensions of V necatrix were sprayed on to tomato (Lycopersicon esculentum Mill) plants maintained in small glasshouses prior to infestation of the plants with L oleracea larvae. The numbers and biomass of pest larvae retrieved from the plants sprayed with V necatrix were significantly reduced by up to 40% and 70%, respectively, compared with plants sprayed with water (control). Similarly, plants sprayed with V necatrix showed a reduction in damage of up to 45% compared with the control plants.     

水稻病虫危害损失和防治效益评估研究初报

2005-2008年笔者在早稻、晚稻生长期间进行防治与不防治对比试验。分析试验数据得出:全程不防治平均减产51.26%,常规防治平均增产113.14%,常规防治平均收益4498.58元/hm2,比全程不防治增86.12%,平均投入产出比1:5.18。拟合出单虫或单病在定局时的发生量(或发生率)与其危害损失之间的线性回归模型:稻飞虱每丛虫量(X)与损失率(Y)之间关系式为Y=8.7654+0.0881X;稻纵卷叶螟卷叶率(X)与损失率(Y)之间关系式为Y=1.9341+0.2851X;二化螟发生率(X)与损失率(Y)之间关系式为Y=1.4182+1.0407X;稻瘟病白穗率(X)与损失率(Y)之间关系式为Y=0.3765+0.9004X;纹枯病病株率(X)与损失率(Y)之间关系式为Y=-2.4469+0.2829X,相关分析均达极显著水平。     

Selection of biological control agents for controlling soil and seed-borne diseases in the field

Different screening methods for selection of biological control agents (BCAs), for controlling soil and seed-borne diseases, are discussed. The shortcomings of laboratory methods focused on mechanism of action are discussed and we conclude that these methods should be used with caution if candidates with multifactorial or plant mediated mechanisms of control are to be obtained. In vitro screens may be useful for specific groups of microorganisms, thus, screens for antibiotics may be relevant for Streptomyces spp., and promising results have been obtained using soil plating or precolonized agar methods to screen for mycoparasitism and competitive saprophytic ability. Experience with screening in the Nordic programme Biological control of seed borne diseases in cereals is summarized. Research in the four participating countries – Finland, Sweden, Norway and Denmark – followed the same paradigm: that of obtaining antagonists, well adapted to different Nordic environments, and developing them as effective BCAs. Potential antagonists were isolated from different sources and in planta screening methods were developed in order to optimize selection of antagonists effective against a range of seed borne pathogens. Screens in the laboratory or greenhouse were followed by screening in the field. The different screening procedures are compared and evaluated.     

青枯病的化学与生物防治研究进展

本文阐述了近年来在植物细菌性青枯病化学和生物防治研究方面所取得的进展。首先介绍了普通化学药剂和抗生素及植物生长调节剂等防治青枯病的新近应用，作用效果和防治特点；然后回顾了应用无致病力青枯菌菌株，拮抗细菌，菌根和基因工程技术进行生物防治的研究情况；最后对化学和生物防治的有关问题及应用前景进行了讨论。     

Laboratory and field investigations using indigenous entomopathogenic nematodes for biological control of Plutella xylostella in Kenya

This study was undertaken to determine the potential utility of entomopathogenic nematodes for management of diamondback moth (DBM) larvae in Kenya. Five Kenyan EPN isolates, Heterorhabditis indica, Steinernema karii, Steinernema weiseri, Steinernema sp. and Heterorhabditis taysearae were tested for their ability to penetrate DBM and their speed of kill (LT₅₀). Heterorhabditis indica and S. weiseri were found to have the quickest rate of kill and S. weiseri was found to have the largest proportion of nematodes penetrating. Three of the isolates, Steinernema sp. (95), S. weiseri and H. indica, were used in a field experiment to test their ability to reduce DBM populations and damage to kale. All three nematodes caused significant reductions in populations of DBM and DBM damage, with the population reductions being similar to those caused by application of Bacillus thuringiensis ssp. kurstaki. This study shows that EPNs have great potential that should be exploited in the management of DBM in Kenya.     

外来入侵豚草天敌广聚萤叶甲的半人工饲料配方和关键因子的初步筛选

广聚萤叶甲Ophraella communa LeSage是入侵恶性豚草的天敌。参照前人对叶甲类半人工饲料的研究配方,采用19因子混水平正交试验L32(45×216),初步筛选出适合广聚萤叶甲成虫和幼虫的半人工饲料配方,筛选出影响广聚萤叶甲成虫寿命的8种关键成分:麦胚、10%KOH、葡萄糖、尼泊金、豚草叶粉、琼脂、胆固醇、大豆油;影响广聚萤叶甲2龄幼虫发育的8种关键成分是:燕麦片、琼脂、麦胚、葡萄糖、氯化胆碱、10%KOH、蒸馏水、大豆油。研究结果为进一步研制广聚萤叶甲人工饲料提供了基础。     

中原地区梨瘿蚊的生物学特性及防治研究

梨瘿蚊在河南1年发生3~4代。翌年3月下旬越冬代成虫开始出现,4-6月为发生为害盛期。平均枝梢被害率,第1代为22.10%,第2代为58.91%。在做好树上化学防治的同时,应注意加强地面防治。龟纹瓢虫、草蛉、小花蝽等对第3代梨瘿蚊具有较好的控制效果,应注意保护和利用。     

Biological control of weeds in European crops: recent achievements and future work

Approaches to the biological control of weeds in arable crops and integration of biological weed control with other methods of weed management are broadly discussed. Various types of integrative approaches to biological control of weeds in crops have been studied within the framework of a concerted European Research Programme (COST‐816). During the period 1994–99, some 25 institutions from 16 countries have concentrated on five target weed complexes. Some major scientific achievements of COST‐816 are: (i) combination of the pathogen Ascochyta caulina with an isolated phytotoxin produced by this fungus to control Chenopodium album in maize and sugar beet; (ii) the elaboration and preliminary field application of a system management approach using the weed:pathogen system Senecio vulgaris:Puccinia lagenophorae to reduce the competitiveness of the weed by inducing and stimulating a disease epidemic; (iii) combination of underseeded green cover with the application of spores of Stagonospora convolvuli to control Convolvulus species in maize; (iv) assessment of the response of different provenances of Amaranthus spp. to infection by Alternaria alternata and Trematophoma lignicola, the development of formulation and delivery techniques and a field survey of native insect species to control Amaranthus spp. in sugar beet and maize; (v) isolation of strains of different Fusarium spp. that infect all the economically important Orobanche spp. and development of novel, storable formulations using mycelia from liquid culture. Although no practical control has yet been reached for any of the five target weeds, potential solutions have been clearly identified. Two major routes may be followed in future work. The first is a technological approach focusing on a single, highly destructive disease cycle of the control agent and optimizing the efficacy and specificity of the agent. The second is an ecological approach based on a better understanding of the interactions among the crop, the weed, the natural antagonist and the environment, which must be managed in order to maximize the spread and impact of an indigenous antagonist on the weed.     

Development of a new dispenser for microbiological control agents and evaluation of dissemination by bumblebees in greenhouse strawberries

BACKGROUND: To date, in modern agriculture, biological control strategies are increasingly becoming the preferred pest management approach. However, the success of microbiological control agents (MCAs) largely depends on efficient dissemination into the crop. The pollinator‐and‐vector technology employs pollinating insects like bees for a better dissemination. In this study, a new dispenser for bumblebee workers of Bombus terrestris L. was developed. Binab‐T‐vector and Prestop‐Mix were used as two typical MCA products for dissemination. RESULTS: In a first series of experiments in the laboratory for optimisation, the newly developed dispenser was a two‐way type dispenser, 20 cm long, with two rectangular compartments and different entrance and exit holes. In addition, the amounts of MCA loaded on the workers were 10 times higher with the new dispenser as compared with the side‐by‐side passageway (SSP) dispenser. Typically, the highest amounts were recovered from the thorax and legs of the workers. In a second series of experiments under greenhouse conditions with the use of queen‐right B. terrestris hives, successful dissemination in strawberry flowers was obtained at different distances from the hive (0–8 m, 8–18 m and 18–21 m), and the workers inoculated the first, second and third flowers that were consecutively visited. In addition, the new dispenser caused no adverse effects on worker foraging intensity, whereas a dramatic reduction was scored with an SSP dispenser. Finally, the data suggested that it is necessary to refill the newly developed dispenser at 3 day intervals. CONCLUSIONS: The results demonstrated that, with the use of the newly developed dispenser, bumblebee workers carried high amounts of MCA, and this resulted in a successful dissemination of MCA into strawberry flowers. Copyright © 2010 Society of Chemical Industry     

河西地区玉米田棉铃虫发生规律及其化学防治技术

近年来,棉铃虫在甘肃省河西地区重度发生,严重阻碍了玉米生产。为有效防治棉铃虫,保障玉米生产安全,本研究调查了玉米田棉铃虫发生规律,介绍了两种高效施药器械的应用,并测定了两种生物农药的田间防治效果。结果表明:棉铃虫在河西地区1年可发生3代。越冬蛹主要分布在0~5cm土层中,占总越冬蛹量的55.56%,2016年玉米连作田平均蛹量200.10头/667m2。越冬蛹于4月下旬开始羽化,羽化高峰为5月中下旬,1代棉铃虫羽化高峰为7月下旬,2代棉铃虫羽化高峰为8月中旬。棉铃虫成虫在玉米不同生育期的产卵习性不同,玉米雌穗吐丝后87.86%的卵着落在花丝上。29℃下,棉铃虫卵期4.53d,幼虫平均历期24.60d,蛹期9.93d,成虫寿命为10.07d,完成一个世代需49.13d。田间防治效果显示,高架喷雾防治效果优于无人机喷雾。甲氨基阿维菌素苯甲酸盐防治效果较Bt高,且速效性好。综上所述,河西地区棉铃虫越冬基数大,以2代棉铃虫为害最重,玉米吐丝期为防治的关键时期,喷雾防治时可优先选用高架喷雾方式。     

黑刺粉虱的发生、为害及其生物防治国内研究概况

黑刺粉虱Aleurocanthus spiniferus为茶园和柑桔园为害严重的粉虱种类之一。本文概述了黑刺粉虱在国内分布、寄主种类、发生与为害等,探讨了近年来生物防治在控制黑刺粉虱为害中的作用,包括寄生性天敌、捕食天敌及昆虫病原性真菌等的利用,以期为黑刺粉虱的综合治理提供参考。