The epigeal predatory arthropods in aubergine fields at South Sumatra (Indonesia) with regard to the plant cover and the use of insecticides

Journal of Plant Diseases and Protection - For the first time, the predatory arthropods of aubergine fields in South Sumatra, Indonesia, were studied by pitfall trapping and by square flooding in...     

溴氰菊酯对南方小花蝽捕食番茄潜叶蛾能力的影响

为探究溴氰菊酯对南方小花蝽Orius similis捕食番茄潜叶蛾 Tuta absoluta能力的影响,本研究以溴氰菊酯对南方小花蝽的致死中浓度为处理浓度,采用药膜法处理南方小花蝽成虫,然后让存活的南方小花蝽取食番茄潜叶蛾卵及1龄幼虫,分析溴氰菊酯对其捕食功能反应及捕食行为的影响。结果表明,经致死中浓度的溴氰菊酯处理后,南方小花蝽捕食番茄潜叶蛾的能力及行为均受到影响,功能反应模型仍符合Holling Ⅱ模型,但南方小花蝽处理猎物的时间延长,控害效能降低,搜寻效应下降, 成虫对卵和1龄幼虫的日最大捕食量分别下降了47.37粒/皿、9.47头/皿;而处理1粒番茄潜叶卵和1头1龄幼虫所用的时间分别延长了777.6 s和3 456.0 s,同时南方小花蝽搜寻、行走、捕食番茄潜叶蛾卵的行为时间分别缩短了444.2、750.2、919.6 s,静止和梳理时间则分别延长了1 677.6、403 s,对番茄潜叶蛾卵和1龄幼虫的捕食量分别降低了4头和1头。因此,溴氰菊酯对南方小花蝽捕食能力产生了抑制作用,在田间防控番茄潜叶蛾时应延长溴氰菊酯与南方小花蝽使用的间隔时间,更好地协调化学与生物防治。     

Availability of pesticide-treated seed on arable fields

A study of the availability of pesticide-treated seed on arable fields was performed. The research was carried out in three different areas of The Netherlands (soil types ranging between sand and heavy clay) and included the following topics: drilling techniques, soil conditions, location on the field and spillage. The results show that there is a large variation among the various crops in the percentage of seed remaining on the soil surface. This is mainly caused by differences in drilling techniques and soil conditions. The percentage of surface seeds after standard drilling is approximately four times higher than after precision drilling. The best correlation for the impact of soil conditions was found for the overall measure of clod weight. Large differences in seed densities (factor of 3.5) were found between the headland and the field centre. Spillage occured in most crops investigated, with an average of two spills per field. Based on the field data it is recommended to use in the current risk assessment for birds and mammals the following percentages of seed remaining on the soil surface: 0.5% for precision drilling, 3.3% for standard drilling in spring and 9.2% for standard drilling in autumn.     

Burial rates of surrogate seeds in arable fields

The probability of seed consumption by surface-dwelling predators depends on the duration of seed exposure on the soil surface. We investigated seed burial using painted ceramic beads as surrogate seeds. Fifty beads of three size classes each were applied to small arenas within crop fields and their fates were followed from August to October. New sets of beads were applied as soon as most beads had disappeared from the soil surface. Bead availability on the soil surface declined immediately after placement, and then declined steadily over time, with increased loss during rain and management practices. Smaller beads were incorporated into the soil/litter matrix more easily than larger beads. Bead burial differed considerably among crop environments, with more burial in forage crops (red clover, lucerne) than in row crops (soyabean, maize). The fact that seed availability differed among crop environments suggests that it can be manipulated to maximise predation risk.     

Influence of pesticides and application methods on pest and predatory arthropods associated with cotton

Incidence of sucking pests was studied in a transgenic (Bt) and non-transgenic cotton (non-Bt) agro ecosystem in 2008 and 2009. Simultaneously, the influence of different pesticides applied in two different methods on sucking pests and generalist predators was investigated on transgenic cotton. In stem application, the insecticides solutions prepared were painted directly on the middle portion of the plant stem but in foliar application the recommended dosages of the insecticides were sprayed on the cotton plant. The transgenic and non-transgenic cotton did not differ significantly in the population of sucking pests. The different pesticides when applied by foliar sprays reduced significantly more sucking pests than stem application. Among the different insecticides used, imidacloprid caused the maximum reduction of the leaf hopper population, acetamiprid caused the maximum whitefly reduction, and clothianidin caused the maximum thrips reduction under foliar application. Via stem application, acetamiprid and thiomethoxam were found better in suppression of the sucking pests?? population, but the population of predators was significantly less disrupted by the stem application method. The foliar application was in general more effective; stem application may be more applicable early in the season when its efficacy was higher and when foliar sprays were particularly destructive to beneficial pests. In foliar application, all the systemic neonicotinoids like imidacloprid, clothianidin, admire, thiamethoxam and acetamiprid were found highly toxic to natural enemies in comparison with spirotetramat, buprofezin and fipronil.     

Water balance,respiration and immobilisation in relation to deltamethrin poisoning and physical conditions in the epigeal spider Oedothorax apicatus

The effect of a pyrethroid insecticide, deltamethrin, on water loss, metabolic rate and immobilisation was studied, using the epigeal spider Oedothorax apicatus (Blackwall) (Linyphiidae) as a test species. Water loss was measured gravimetrically at different temperatures, air humidities, and doses of deltamethrin. Metabolic rate and immobilisation were measured at different temperatures and doses. Immobilisation was measured at different relative humidities and temperatures. Water loss due to evaporation increased linearly with vapour pressure deficit. The slope of the latter relationship increased with temperature, indicating an increase in cuticle permeability with temperature. In addition to water loss by evaporation, deltamethrin treatment induced water excretion. This was positively related to dose and temperature, but independent of air humidity. Metabolic rate increased with temperature and dose. Immobilisation was highest at low temperatures in combination with low air humidity. The consequences of pesticide-induced water excretion are discussed with respect to field- and laboratory-based dose-effect relationships for pyrethroids presented in the literature. The present results seem to offer an explanation for hitherto unexplained minima in temperature-response curves in pyrethroid toxicity in some arthropod species. It is concluded that simultaneous measurements of metabolic rate, water-loss rate and pesticide effects are a prerequisite for an understanding of the effects of pesticides on arthropods.     

锐劲特对稻田主要捕食性天敌影响的研究

采用田间试验的方法,进行了锐劲特、三唑磷、杀虫双及锐劲特与甲胺磷混用对稻田主要捕食性天敌影响的研究。结果表明,施用5%锐劲特SC30ml/亩1次,药后28d,对天敌的杀伤率分别为蜘蛛0.92%、瓢虫2.97%、步甲3.33%、隐翅虫6.83%、宽黾蝽7.14%,低于18%杀虫双AS250ml/亩及20%三唑磷EC120ml/亩2次的杀伤率。5%锐劲特SC10ml/亩+50%甲胺磷EC80ml/亩对天敌的杀伤作用较大。     

转基因耐草甘膦大豆对豆田节肢动物群落多样性的影响

在田间试验条件下,采用直接观察法,通过对多样性指数、优势集中性指数、均匀性指数、物种数的分析比较,研究转基因耐草甘膦大豆对豆田节肢动物群落多样性的影响。结果显示,大豆生长期转基因耐草甘膦大豆和受体的节肢动物多样性指数、均匀性指数、物种数均显著低于当地常规品种,优势集中性指数显著高于当地常规品种,但转基因抗草甘膦大豆与对照受体间各指标无显著性差异,说明转基因耐草甘膦大豆对豆田节肢动物群落无明显影响。     

地黄田节肢动物类群结构及其多样性研究

通过2007年6～11月对陕西省汉中市汉台区地黄田节肢动物群落结构及其多样性进行的调查研究表明,田间节肢动物共73种,分属于2纲,11目,45科。其中以鳞翅目和鞘翅目的丰富度和优势度最高,多样性指数和均匀度以同翅目最高。地黄田天敌数量多,以膜翅目丰富度和多样性最高,以蜘蛛类均匀度和优势度最高。时间动态分析表明,8月份地黄田昆虫数量最多,物种数最丰富,多样性最高。因此,8月是地黄田进行害虫防治的关键时期。     

扇吸式太阳能杀虫灯在鲜食玉米田的应用效果及对节肢动物生物多样性的影响

为明确扇吸式杀虫灯在鲜食玉米田间的应用效果及对节肢动物生物多样性的影响,采用抽样鉴定方法调查扇吸式杀虫灯的诱虫谱,通过田间试验调查其对主要害虫亚洲玉米螟Ostrinia furnacalis的控制范围和防控效果,并采用黄板、糖醋酒液和陷阱法取样调查其对玉米田间节肢动物生物多样性的影响。结果表明,扇吸式杀虫灯在鲜食玉米田可诱集9目40科的昆虫,对亚洲玉米螟的有效控制距离在60 m左右,单灯控制面积约1.1 hm²。在大喇叭口期,灯光防控处理对亚洲玉米螟的株防效为25.83%,显著低于化学防控处理的76.74%;在乳熟期,化学防控处理的虫孔减退率为75.29%,显著高于灯光防控处理的21.18%,灯光防控处理、化学防控处理和对照的茎秆活虫数、虫孔隧道长度和雌穗防效差异均不显著。距灯80 m范围内不同距离的主要害虫与天敌种群数量基本一致,玉米不同生育期节肢动物群落多样性指数、均匀性指数、优势集中性指数和相似系数变化较大,但在同一生育期不同距离间均无显著差异,说明田间节肢动物群落主要受玉米生育期的影响,扇吸式杀虫灯对田间主要害虫和天敌种群无显著影响。表明扇吸式杀虫灯对亚洲玉米螟的防治效果有限,对田间节肢动物多样性无显著影响,可作为鲜食玉米田防治亚洲玉米螟的辅助手段,但无法替代化学防治。     

紫花苜蓿田蝗虫发生规律初步研究

蝗虫是紫花苜蓿田的主要害虫。1999～2005年,对滨州市紫花苜蓿田发生的蝗虫种类进行了调查,结果表明,共有蝗虫18种;并对其中4个喜食紫花苜蓿优势种的生活史、生活习性、发生条件、为害特点等进行了研究,进而提出防治策略。     

Weed flora in arable fields of eastern Ethiopia with emphasis on the occurrence of Parthenium hysterophorus

An exploratory weed survey was carried out on 240 crop fields in eastern Ethiopia to assess the influence of some environmental and crop management factors on weed species composition and distribution, and to investigate the association of the recently introduced Parthenium hysterophorus L. with other components of the weed flora. A total of 102 weed taxa belonging to 36 plant families were recorded. Asteraceae, Poaceae and Fabaceae were the most abundant families based on the number of species recorded. Digitaria abyssinica (Hochst. Ex A. Rich) Stapf was the most frequent species (63%) and Parthenium hysterophorus the second most frequent (54%). The latter species was ranked as the most important weed by 90% of the farmers in the lowlands while 86% of the farmers in the highlands ranked the former species as the worst weed. According to a partial canonical correspondence analysis (pCCA), altitude, rainfall, month of planting, number of weedings and soil type were the major environmental/crop management factors influencing the species distribution in the study area. The first pCCA axis clearly structured highland and lowland weed species while the second axis distinguished those species that grow on sandy soils. Parthenium hysterophorus has, in a very short time period, emerged as one of the most troublesome weed species in eastern Ethiopia.     

Studies on the comparative effectiveness of permethrin and deet against bloodsucking arthropods

A comparison was made of the effectiveness of permethrin and deet against Ornithodoros parkeri (Acari: Argasidae), Leptotrombidium fletcheri (Acari: Trombiculidae), Rhodnius prolixus (Heteroptera: Reduviidae), Phlebotomus papatasi and Lutzomyia longipalpis (Diptera: Psychodidae), Anopheles Stephensi, Anopheles albimanus, Aedes taeniorhynchus, Aedes aegypti and Culex pipiens (Diptera: Culicidae), Glossina morsitans (Diptera: Glossinidae) and Xenopsylla cheopis (Siphonaptera: Pulicidae), using dose-response methods. At the ED₉₅ (95% effective dose) level, deet was more potent (P<0.05) than permethrin against all species except O. parkeri and R. prolixus. In addition, the slope of the dose-response line for deet was greater than that for permethrin against all species except O. parkeri and R. prolixus. Permethrin exhibited repellent and/or toxic effects, depending on the dose used and the individual tolerances of members of the insect test population.     

广德县油菜蚜虫发生规律调查初报

广德县油菜蚜虫发生高峰出现于11月20日至12月20日,为全生育期主峰,大发生年可随冬后气温回升出现第二高峰。两峰与油菜营养生长旺盛期(四至七叶期)、蕾薹期有对应关系。暖冬及早春温暖干旱天气容易导致大发生;低温多雨、田间潮湿、多杂草对蚜虫种群发展不利。有翅蚜数量与蚜虫总量呈极显著正相关关系。     

白菜根肿病田间发生消长规律研究

白菜根肿病是由鞭毛菌亚门根肿菌纲根肿菌属的双鞭毛菌(PlasmodiophorabrassicaeWoronin)为害白菜根部导致其肿大、植株枯萎死亡的病害。为了了解其发生为害消长情况,为指导防治提供依据,本站于2001年6月至2002年6月,在根肿病发生较重的红塔区郑井11组郑文祥的蔬菜地中种植大白菜进行其发生为害消长观察。现将观察研究结果总结如下:1观察方法白菜品种选用山东大白菜良种服务中心繁育的大白菜19,撒播,从2001年6月至2002年6月共播种6批。各批次播种时间分别为2001年的6月25日、8月12日、10月1日、12月29日,2002年的3月16日、5月2日。白菜出苗…     

The effect of drop size and velocity on the performance of agricultural sprays

The sizes and velocities of drops in sprays from farm sprayers are considered in relation to their impaction on plant surfaces. Examples from a study being carried out at the National Institute of Agricultural Engineering (NIAE) are given. The results showed that young leaves of barley (cv Mazurka) and wild oats (Avena fatua L.) were difficult to wet, only the smallest drops applied (about 100 um diameter) being readily retained. In the context of weed control in cereals the importance of detrmining the effect of the form of plant deposits on herbicidal activity is discussed, and examples of results of a joint study between the NIAE and the Agricultural Research Council Weed Research Organization are given.