绿僵菌对甘蔗螟虫的室内致病力测定

在室内用喷雾法测定了4株绿僵菌对甘蔗螟虫3～4龄若虫的致病力。结果表明,绿僵菌致病力强弱与菌株种类和接种剂量有密切关系。先接虫后喷施菌剂时,菌株对甘蔗螟虫若虫致病力的强弱顺序为JF813HS1MA4JF883;先喷施菌剂后接虫时,菌株对甘蔗螟虫若虫致病力的强弱顺序为MA4HS1JF813JF883。在接种各菌株孢子浓度为1×108个/mL时,菌剂对甘蔗螟虫若虫的致死率高。其中JF813菌株对甘蔗螟虫若虫具有很强的二次侵染能力,HS1菌株在两种处理方式中致病力稳定。     

玉米螟白僵菌高致病性菌株筛选

对7株寄生玉米螟的白僵菌菌株产孢量、营养生长量、孢子萌发速率生物学特性指标及对玉米螟3龄幼虫致病力进行了测定,筛选对玉米螟高致病性白僵菌菌株。结果表明:不同菌株间存在较大的差异,综合各项生物学特性指标数据,筛选出生物学特性表现优良的高致病性菌株1株,即BC6菌株。BC6菌株产孢量达到18.35×107个/cm2,14 h的萌发率为96.59%,营养生长量为2.722 mm/d。通过对玉米螟3龄幼虫致病力的测定,校正死亡率达到了90%。各项生物学特性指标均显著高于实验室原有对照(CK)菌株,具有工厂化生产潜力和实际应用价值。     

甘蔗品种生长中后期对螟虫抗性综合评价

采用螟虫自然侵染的方法,以螟害节率为甘蔗生长中后期抗螟性指标,分析19个甘蔗品种(系)在新植和宿根条件下对螟虫的抗性。结果表明:在该试验地,黄螟是甘蔗生长中后期的优势种,条螟次之,二点螟最少。3种螟虫的抗螟性指标均在19个甘蔗品种(系)间存在显著差异,甘蔗品种(系)对3种螟虫的抗性均存在显著的基因型效应。甘蔗品种(系)对黄螟和二点螟的抗性还存在显著的植期效应、植期和基因型互作效应,其中植期对黄螟和二点螟的种群数量影响最大。3种螟虫的抗螟性指标均在两个植期间显著正相关,但同一植期内3种螟虫的抗螟性指标间相关性不显著。综合评价各甘蔗品种(系)对3种螟虫的抗性水平,柳城05-136、云蔗03-258、粤甘42号和桂糖30号在供试甘蔗品种(系)中对3种螟虫均表现出较高抗性。     

绿僵菌对荔枝椿象的室内致病力测定

在室内用喷雾法测定了4株绿僵菌对荔枝椿象3～4龄若虫的致病力.结果表明,绿僵菌致病力强弱与菌株种类和接种剂量有密切关系.菌株对荔枝椿象若虫致病力的强弱顺序为J813MA4J86CMA3.在接种菌株J813孢子浓度为1×108个/mL的情况下,对荔枝椿象若虫的LT50为7.63 d.J813菌株对荔枝椿象若虫具有很强的二次侵染能力.     

甘蔗二点螟发生规律、预测方法和防治技术

调查甘蔗二点螟的发生规律，研究预测方法和防治技术，以解决生产上存在的二点螟为害，造成甘蔗产量严重损失的难题。     

金龟子绿僵菌对红棕象甲的室内致病力测定

在室内用喷雾法测定13株绿僵菌对红棕象甲的致病力。结果表明,菌株致病力强弱与菌株种类有密切关系,菌株的浓度与累计死亡率成线性关系。菌株对红棕象甲的致病力由强到弱的顺序为：Red2＞Red3＞Gre1＞Yx7＞Yx4＞Gre3＞Red1＞Yx1＞Gre2＞Yx6＞Gre4＞Gre5＞Yx3。接种Red2菌株在孢子浓度为1.0×108个/mL水悬浮剂情况下,对4龄红棕象甲幼虫的LT50为5.23 d。用不同浓度的Red2菌株的孢子油悬浮剂涂抹法接种4龄幼虫,发现其LC50为7.32×106个/mL。另外,经试     

发光杆菌NJ代谢物对大豆胞囊线虫的作用研究

为研究发光杆菌NJ菌株对大豆胞囊线虫的生防作用,测定了其代谢物原液及不同浓度稀释液对大豆胞囊线虫卵孵化及二龄幼虫活性的影响。结果表明,在原液、20%、10%、4%稀释液浓度下,对卵孵化的相对抑制率分别是97.30%、84.11%、32.09%、25.41%,与无菌水对照差异显著,而其它稀释度抑制率较低;对二龄幼虫24h的校正死亡率分别是100%、70.97%、50.41%、36.78%,均与无菌水对照差异显著。线虫死亡率随着时间的延长而增加,48h后,4%稀释液线虫校正死亡率高达63.82%,而2%稀释液线虫校正死亡率也达42.95%。72h后2%稀释液的线虫校正死亡率达61.73%。     

金龟子绿僵菌与4种植物源农药的相容性研究

为了明确杀虫真菌绿僵菌与常用的植物源农药之间的相容性,本研究测定了4种植物源农药(苦参碱、鱼藤酮、印楝素和除虫菊素)对绿僵菌Ma41孢子萌发、菌丝生长及产孢量的影响.试验结果表明;除虫菊素与绿僵菌的相容性最好,虽然在常用浓度下,对孢子萌发抑制率和产孢量抑制率分别为51.95％和44.50％,但在亚致死浓度和次亚致死浓度下,对孢子萌发、菌丝生长和产孢的抑制作用都较弱.苦参碱与绿僵菌也有较好的相容性,虽然在常用浓度和亚致死浓度下,对绿僵菌产孢的抑制率达66.08％和55.84％,但在3种试验浓度下,其对孢子萌发和菌丝生长的抑制作用都较小.此外,鱼藤酮和印楝素与绿僵菌的相容性差.     

蔗叶粉碎还田对甘蔗螟虫发生的影响

根据生产上甘蔗收获期蔗叶处理方法的不同,通过田间试验,测定了蔗叶焚烧和蔗叶粉碎还田对当年宿根蔗的甘蔗螟虫发生的影响.结果表明:在苗期,甘蔗螟虫以二点螟为主;在甘蔗生长中后期,条螟、黄螟和二点螟混合发生为害,但条螟种群数量最大.与蔗叶焚烧处理相比,蔗叶粉碎还田处理中,螟害导致的螟害株率相当,分别为94.17％和91.39％,但枯心率和螟害节率均显著降低,分别为43.86％、12.29％和17.23％、13.57％,表明蔗叶粉碎还田有利于减轻甘蔗螟虫为害.     

小麦条锈菌夏孢子保存时间及存活力评价

为在RNA水平上快速检测小麦条锈菌夏孢子的存活力和致病性,选取-20℃下保存1年和10年的菌株,检测小麦条锈菌夏孢子RNA产量和完整性,并通过室内人工接种实验鉴定其致病性。结果表明,RNA产量高于600 ng·mg^-1的夏孢子具有致病性,低于600 ng·mg^-1的夏孢子均已丧失致病性;RNA完整性好的菌株,其存活力高,潜育期和致病性与新鲜夏孢子基本一致,RNA完整性差的菌株存活力低,潜育期延长,致病性弱;RNA严重降解的菌株存活率极低或失活,完全丧失致病性。因此,通过检测小麦条锈菌夏孢子RNA的产量和完整性可以评估其存活力和致病性。     

昆虫病原线虫对大豆地下害虫东北大黑鳃金龟幼虫的致病力研究

蛴螬是一种对大豆为害严重的地下害虫.本试验应用昆虫病原线虫(Entomopathogenic nematode,EPN)斯氏线虫Steinernema carpocapsae的4个品系和异小杆线虫Heterorhabditis bacteriophora的3个品系,分别以滤纸和沙子为介质对东北大黑鳃金龟幼虫进行致病力测定,筛选出异小杆线虫Heterorhabditis bacteriophora-1品系为防治东北大黑鳃金龟幼虫的较理想线虫品系,以沙子为介质时,校正寄生死亡率达95.83%.     

Susceptibility of field populations of Blattella germanica (Blattaria: Blattellidae) to spinosad

The German cockroach is an important household insect pest worldwide and acts as a mechanical vector and reservoir for pathogenic agents. The aim of this study was to examine the basic laboratory toxicity of Blattella germanica to spinosad. The M, T, A22, AZAR4, BOOSTAN7 and ABAN21 strains were collected from field populations of six infested kitchen student dormitories and the SAMAN strain was collected from a residential area after insecticide spraying control failure in Tehran, Iran. Technical grade spinosad was delivered in 0.5 microL acetone to the first abdominal sternum of briefly CO2-anesthetize adult male cockroaches by topical application bioassay. Treated males monitored for mortality. Mortality data from the replicates was assessed by probit analysis. The average LD50 of susceptible strain was 494.3, 148.8 and 55.1 ng per insect after 24, 48 and 72 h, respectively. The LD50 of spinosad decreased with time in the field population strains. All German cockroach strains showed a similar susceptibility or lower tolerance (1.6-folds) for spinosad compared with the susceptible laboratory strain and the steep slopes of dose-response curves indicated that the field population of these German cockroach strains was homogenous in response to spinosad. These results indicated that the spinosad was relatively slow-acting in topical application bioassay, with LD50 values decreasing until 72 h and becoming stable thereafter. The effectiveness of spinosad against susceptible and the field population German cockroach strains in laboratory condition showed that spinosad probably could be useful for the control of the German cockroach.     

创制转Mad1基因球孢白僵菌工程菌株提高对玉米螟毒力

克隆来源于生防真菌绿僵菌的黏着蛋白基因Mad1,构建含玉米瘤黑粉菌热激蛋白启动子hsp70和以抗萎锈灵基因carboxin为筛选标记的遗传转化载体上,利用PEG介导的原生质体转化法导入到受体球孢白僵菌菌株D1-5中,获得转化子,经继代培养及分子检测,获得遗传稳定的基因工程菌株。利用蝗虫后翅及洋葱表皮进行吸附试验进行工程菌株的生物学功能鉴定,结果表明,野生型和工程菌的分生孢子对于洋葱表皮的吸附量无明显差异,工程菌的分生孢子对蝗虫翅膀的吸附显著高于野生型,表明Mad1基因的导入能够增加球孢白僵菌对昆虫组织的吸附,对植物表皮组织不存在吸附能力。对亚洲玉米螟幼虫室内毒力测定结果表明,转化后的工程菌株致死中时间比野生型缩短34.07%,杀虫效率显著提高。     

Functional dominance of different aged larvae of Bt-resistant Spodoptera frugiperda (Lepidoptera: Noctuidae) on transgenic maize expressing Vip3Aa20 protein

Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is the main target pest of transgenic maize expressing insecticidal proteins from Bacillus thuringiensis Berliner (Bt) in Brazil. To optimize resistance management strategies, we evaluated the functional dominance of different aged larvae of Bt-resistant FAW on Vip3Aa20 maize. We measured the survival and development of Vip3Aa20-resistant, -heterozygote, and -susceptible strains on MIR162 (expressing Vip3Aa20) and Bt11 × MIR162 × GA21 (expressing Vip3Aa20 and Cry1Ab) maize. The resistant strain, from neonate to sixth instar, showed more than 72% survival on Vip3Aa20 maize. From surviving larvae, more than 64 and 54% developed to pupae and adults, respectively. In contrast, heterozygote and susceptible strains showed no larval survival up to fourth instar, and less than 25% larval survival in the fifth and sixth instar on Vip3Aa20 maize. These larvae produced less than 21% of pupae and adults. The development time of FAW strains from neonate-to-adult exposed to Vip3Aa20 maize was similar; however, the resistant strain showed an increase of ∼ 2 d when compared to those fed only non-Bt maize. In summary, the resistance of S. frugiperda to Vip3Aa20 maize is functionally recessive from neonate up to fourth instar larvae. However, high larval survival of resistant strain and some survival of heterozygote larvae in advanced instars on Vip3Aa20 maize were observed. These results will be important for designing insect resistance management to Bt maize plants expressing Vip3Aa20 protein in Brazil.     

广西南宁地区龙眼害虫群落结构及其动态研究

根据龙眼害虫群落内部物种的组成和数量，采用群落的几个参数进行分析和探讨群落内部的演替规律。结果表明，为害龙眼的害虫有３１科６７属７６种。优势种有１３种。每年３－９月是主要害虫发生为害高峰期。是生产中防治的重要。多样性指数以５、６月份最高。２月份最低。害虫生物学特性、树龄、气候条件和生态环境等都是影响害虫群落结构的主要因子。     

Biochemistry of pyrethroid resistance in German cockroach (Dictyoptera, Blatellidae) from hospitals of Sari, Iran

BACKGROUND: The German cockroach is an important household insect pest mechanically involved in transmission of a variety of diseases to humans. Different classes of insecticides have extensively been used for its control leading to insecticide resistance development. Hence, for an optimal control of this pest, the status and underlying mechanisms of insecticide resistance should be studied in this group of insects. METHODS: Adult German cockroaches were collected from Imam and Bouali Cina Hospitals (Sari, Iran) and subjected to bioassay using jar test method. The results were compared to those of a susceptible laboratory strain. Biochemical assays of esterases, monooxigenases and glutathione S-transferase (GST) levels were undertaken on German cockroaches from Imam and Bouali Cina Hospitals and the results were compared to a susceptible laboratory strain. RESULTS: The LT50 values of the three strains were 20.24+/-2.2, 19.87+/-2.3 and 8.89+/-0.26 for permethrin; 19.3+/-3.05, 17.6+/-0.68 and 8.8+/-0.99 for deltamethrin; 19.64+/-2.9, 18.66+/-3.45 and 8.64+/-0.62 min for cypermethrin, respectively. The mean -esterase activity of Imam and Bouali Cina Hospitals and susceptible strains were 6.941x10(-4), 6.940x10(-4) and 8.01x10(-5) nmol/min/mg protein; the mean -esterase activity in those strains were 5.8x10(-4), 4.25x10(-4) and 7.28x10(-5) nmol/min/mg protein; the mean content of p450 in the above-mentioned strains were 5.64x10(-6), 1.89x10(-6) and 1.2x10(-6) nmol/mg protein; the mean GST activity were 6.66x10(-2), 0.102 and 5.72x10(-2) mol/min/mg protein, respectively. CONCLUSION: The LT50 values and also the mean activity of all enzyme groups in field strains were significantly different from those of the susceptible strain, indicating a vigour tolerance to insecticides and pyrethroids in particular. Hence, insecticide resistance monitoring techniques should be put in place and also resistance management strategies and measures should be considered implementing in the area.     

Dry and Rainy Seasons Significantly Alter the Gut Microbiome Composition and Reveal a Key Enterococcus sp. (Lactobacillales: Enterococcaceae) Core Component in Spodoptera frugiperda (Lepidoptera: Noctuidae) Corn Strain From Northwestern Colombia

Spodoptera frugiperda is a polyphagous pest of several crops of economic importance. Nowadays, the insect is broadly distributed in America and, recently, in Africa, Asia, and Australia. The species has diverged into corn and rice strains. The role of the gut microbiota in insect physiology is relevant due to its participation in crucial functions. However, knowledge of seasonal variations that alter the gut microbiome in pests is limited. Gut microbiome composition between the dry and rainy seasons was analyzed with cultured and uncultured approaches in S. frugiperda corn strain larvae collected at Northwest Colombia, as seasonal microbiome changes might fluctuate due to environmental changes. On the basis of culture-dependent methods, results show well-defined microbiota with bacterial isolates belonging to Enterococcus, Klebsiella (Enterobacteriales: Enterobacteriaceae), Enterobacter (Enterobacterales: Enterobacteriaceae), and Bacillus (Bacillales: Bacillaceae) genera. The community composition displayed a low bacterial diversity across all samples. The core community detected with uncultured methods was composed of Enterococcus, Erysipelatoclostridium (Erysipelotrichales: Erysipelotrichaceae), Rasltonia (Burkholderiales: Burkholderiaceae), and Rhizobium (Hyphomicrobiales: Rhizobiaceae) genera, and Enterobacteriaceae family members. Significant differences in microbiome diversity were observed between the two seasons. The relative abundance of Erysipelatoclostridium was high in the dry season, while in the phylotype ZOR0006 (Erysipelotrichales: Erysipelotrichaceae) and Tyzzerella (Lachnospirales: Lachnospiraceae) genus, the relative abundance was high in the rainy season. The overall low gut bacterial diversity observed in the S. frugiperda corn strain suggests a strong presence of antagonist activity as a selection factor possibly arising from the host, the dominant bacterial types, or the material ingested. Targeting the stability and predominance of this core microbiome could be an additional alternative to pest control strategies, particularly in this moth.     

Factors determining adoption of integrated pest management by vegetable growers in Nakhon Ratchasima Province,Thailand

Widespread use of highly toxic pesticides primarily for agricultural purpose has generated increasing concerns about the negative impact of pesticides on human health and the environment. Integrated pest management (IPM) usually seeks to minimize the use of pesticides and can be utilized to solve pest problems while minimizing risks to people and the environment. A total of 220 vegetable farmers in Nakhon Ratchasima Province of Thailand was interviewed with the objective of investigating the factors determining their adoption or non-adoption of IPM practices. The findings demonstrated that farmers had different uncompromising reasons for determining the use of IPM for their insect pest management. Higher costs of insecticides (91%), adverse effects of insecticides on human health and the environment (80%), and a greater risk of insect pests developing resistance to insecticides (28%) were the primary reasons for the adoption of IPM by vegetable growers in the study area. The reasons for the rejection of IPM practice were unsuitability of IPM for a large farm (52%), implementation difficulties (80%) and a greater belief in synthetic insecticides and their efficacy for target pest control (39%). A comparison between the IPM and the non-IPM farmers showed a significant difference (P < 0.01) in farmers' knowledge of pest management, which influenced IPM adoption or non-adoption. The IPM farmers had greater knowledge about identifying natural enemies and their beneficial role in controlling insect pests, about plant extracts and their efficacy in controlling insect pests and about sticky traps and their efficacy in monitoring natural enemies and controlling insect pests. For example, 24% of IPM farmers had knowledge of natural enemies whereas it was only 4% for the non-IPM farmers. A logistic regression model was fitted which showed that lower cost of pest management, better knowledge on IPM after training and availability of extension services were the factors which influenced farmers' adoption of IPM practice. The non-IPM farmers rejected adoption of IPM due to the common belief that natural enemies would not be effective in controlling insect pests and yields of vegetables would not be increased by practicing IPM.     

导入外源DNA大豆后代的抗虫性鉴定与筛选

大豆食心虫（Leguwinivora glycinivorella)和大豆蚜虫（Aphid glycines)是东北大豆生产的主要虫害。为拓宽资源的利用，创造抗虫大豆种质，用花粉管通道技术向大豆品种吉20、吉25、吉27、吉30等导入皂角（Gleditisia japonica)、鹰嘴豆（Cicer arietinum)和农家早期品种DNA，对从后代中选出的变异系进行了多年抗虫性鉴定和筛选，得到了抗虫品系4个。本文报告了抗虫鉴定筛选结果。