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1.
This paper reports for the first time on farmers’ knowledge, perceptions and management practices of the fall armyworm (Spodoptera frugiperda) in Ethiopia and Kenya. A survey of 343 smallholder maize farmers was conducted. Most farmers in Ethiopia and Kenya had knowledge about fall armyworm; they could identify it mainly during its larval stage. Furthermore, most farmers in Ethiopia (93%) and Kenya (97%) encountered damage by fall armyworm in their farms. They estimated an average of 32% crop damage in Ethiopia and 47.3% of crop damage in Kenya, with an estimated yield reduction between 0.8 to 1 tonnes/ha. Nearly half of the farmers relied on chemical insecticides to control this pest. The majority (60%) of the farmers in Kenya perceived that insecticides were not effective in controlling fall armyworm as compared to most farmers (46%) in Ethiopia who perceived that chemical spray is effective for the control of fall armyworm. In Ethiopia, 26% of the farmers combined handpicking larvae with insecticide sprays, whilst 15% of the farmers practiced only handpicking. The present study highlights the need to develop management strategies for fall armyworm based on farmers’ needs and priorities.  相似文献   

2.
Abstract

We determined fall armyworm abundance, infestation and damage on maize in smallholder farmers’ fields in the Zambezi Valley in northern Zimbabwe. Data were collected through field measurements at four sites and interviews with 101 farmers. Fall armyworm abundance ranged from 13.7 to 33.3 larvae per 30 plants, with infestation exceeding 94% and leaf, silk and tassel damage levels ranging between 25 and 50%. Most larvae on maize plants (P?<?0.05) were at instar stages 2 to 3. Estimated grain yield decrease was 58%. Echinochloa colona and Amaranthus spp. were also damaged by fall armyworm. Farmers experimented with 28 combinations of pesticides, ash, and washing powders. Sixty five percent of the farmers used restricted to highly restricted pesticides. High fall armyworm abundance, infestation and maize damage levels suggest that the Zambezi Valley could become a fall armyworm hotspot. Sequential damage of plant parts signified the persistence of this pest in the study area. We recommend large-scale interventions that include chemical and biological control methods as well as destroying ratoon hosts, publishing information about locally available pesticides for the control of fall armyworm, and farmer training on fall armyworm biology and correct use of pesticides.  相似文献   

3.
国外草地贪夜蛾化学防治技术的研究与应用   总被引:4,自引:0,他引:4  
草地贪夜蛾Spodoptera frugiperda(J.E.Smith)是一种适应性和迁徙能力很强的农业害虫,并具有暴发为害的特点。几十年来,化学防治一直是防治草地贪夜蛾的重要技术措施。20世纪80年代以前,美洲国家防治草地贪夜蛾以有机磷类和氨基甲酸酯类杀虫剂为主;随后拟除虫菊酯类杀虫剂得到了广泛使用;20世纪90年代中后期,美洲特别是美国推广种植转基因Bt玉米后,防治草地贪夜蛾杀虫剂的用量显著减少;近年来,甲氨基阿维菌素苯甲酸盐、乙基多杀菌素、除虫脲、虱螨脲、茚虫威、氯虫苯甲酰胺、氟苯虫酰胺、溴氰虫酰胺等一系列新型杀虫剂品种在防治草地贪夜蛾中发挥了突出的作用。伴随着不同种类杀虫剂的使用,草地贪夜蛾对杀虫剂抗性也相应地呈现出明显的变化,20世纪80年代后,美洲的草地贪夜蛾先后对有机磷类和氨基甲酸酯类杀虫剂产生了抗药性,截至2017年,美洲地区的草地贪夜蛾至少对包括氨基甲酸酯类、有机磷类、拟除虫菊酯类及Bt杀虫蛋白等不同类型共29种杀虫剂产生了抗药性;2016年,采自北美洲波多黎各的草地贪夜蛾田间种群对双酰胺类杀虫剂氟苯虫酰胺和氯虫苯甲酰胺抗性倍数最高分别达500倍和160倍。草地贪夜蛾的抗药性机制主要是解毒代谢增强和靶标基因突变。种子处理可以预防作物苗期草地贪夜蛾的为害,并且有利于天敌保护。雾滴粒径不仅影响杀虫剂对草地贪夜蛾的防治效果,还影响草地贪夜蛾对杀虫剂抗药性的发展,因此,防治田间草地贪夜蛾适宜采用细雾喷雾方式。使用得当,化学杀虫剂可以与天敌和生物杀虫剂协同增效防治草地贪夜蛾。航空施药要和地面施药联合使用才能对玉米田严重发生的草地贪夜蛾达到好的防治效果。  相似文献   

4.
Abstract

Natural enemy abundance and impact on fall armyworm, Spodoptera frugiperda (J. E. Smith), populations were compared in sugar-treated and water-treated maize fields in Honduras. Counts of natural enemy abundance were made immediately after and also 1 week following sugar applications. Higher numbers of natural enemies were found in sugar-treated maize than in maize treated with water alone. The most abundant species were Solenopsis geminata (F.) (Hymenoptera; Formicidae), Lespesia archippivora (Riley) (Diptera; Tachinidae) and Doru taeniatum (Dorhn) (Dermaptera; Forficulidae). Of these species, S. geminata and L. archippivora showed consistently higher numbers in sugar-treated maize than in water-trated maize. Coccinellids were also consistently concentrated in sugar-treated maize, although they were not as abundant as either S. geminata and L. archippivora . In sugartreated maize, average leaf area damaged by fall armyworm was reduced by 35% and average fall armyworm infestation rates were 18% lower. These findings suggest that applications of sugar to maize can concentrate natural enemies and that these natural enemies reduce fall armyworm populations and damage.  相似文献   

5.
采用植保无人机和机动喷雾器2种施药方法,开展了氯虫苯甲酰胺、茚虫威2种农药对玉米草地贪夜蛾的田间防效试验。结果表明,采用2种施药械施药对2种农药的田间防效均没有显著差异。200g/L氯虫苯甲酰胺悬浮剂15mL/667m 2药后7d防效最高,植保无人机施药和机动喷雾器施药防效分别为89.0%、91.8%,叶片保护率分别为86.5%、88.3%。150g/L茚虫威乳油18mL/667m 2药后3d防效最高,植保无人机施药和机动喷雾器施药防效分别为85.5%、85.2%,叶片保护率分别为75.8%、76.4%。茚虫威表现出较好的速效性,氯虫苯甲酰胺表现出更长的持效性。  相似文献   

6.
国产Bt-Cry1Ab和Bt-(Cry1Ab+Vip3Aa)玉米对草地贪夜蛾的抗性测定   总被引:1,自引:0,他引:1  
草地贪夜蛾Spodoptera frugiperda(J.E.Smith)是世界性重大农业害虫。种植转基因Bt作物是主要的防治手段之一。我们利用室内生物测定方法评价了国产Bt-Cry1Ab玉米(转化体C0030.3.5)和Bt-(Cry1Ab+Vip3Aa)玉米(转化体DBN3601和DBN3608)对草地贪夜蛾1~4龄幼虫的毒力。结果显示,供试两种转基因玉米共6个品种皆可高效表达目标杀虫蛋白并对草地贪夜蛾具有很强的毒杀作用,对1龄幼虫的致死率达到59%~100%,存活幼虫的生长发育亦受到显著抑制。表明国内研发的Bt-Cry1Ab玉米和Bt-(Cry1Ab+Vip3Aa)玉米对草地贪夜蛾具有良好的控制效果,其中Bt-(Cry1Ab+Vip3Aa)玉米的防治效果显著优于Bt-Cry1Ab玉米,两种转基因玉米皆具有较好的商业化应用前景。  相似文献   

7.
The effects of sub-lethal residues of azinphos-methyl on pheromone production, calling, female attractiveness and the ability of males to locate sources of natural and synthetic pheromone were compared in azinphos-methyl-susceptible (susceptible) and azinphos-methyl-resistant (resistant) obliquebanded leafrollers, Choristoneura rosaceana (Harris). The amount of pheromone in susceptible females was reduced by 29-33% after exposure to azinphos-methyl; this treatment did not affect the pheromone content of resistant females. Azinphos-methyl-treated resistant females contained 39-43% less pheromone than azinphos-methyl-treated susceptible females. Resistant females that were not treated with azinphos-methyl contained 35-56% less pheromone than susceptible females that were not treated with insecticide. The incidence of calling was reduced by 67-100% in azinphos-methyl-treated susceptible females; the incidence of calling by resistant females was not affected by exposure to azinphos-methyl. The incidence of calling by azinphos-methyl-treated susceptible females was 58-100% lower than that of azinphos-methyl-treated resistant females. There was no difference in the incidence of calling between susceptible and resistant females that had not been treated with insecticide. In a flight tunnel, treatment with insecticide reduced the attractiveness of susceptible females by 38%; treatment with insecticide did not affect the attractiveness of resistant females. There was no difference in the proportion of males attracted to susceptible and resistant females that had, or had not been treated with insecticide. In an apple orchard, the attractiveness of susceptible and resistant females treated with azinphos-methyl was reduced by 84 and 12%, respectively. The proportion of males attracted to azinphos-methyl-treated susceptible females was 58% lower than the proportion attracted to azinphos-methyl-treated resistant females, whereas, if females were not treated with insecticide, the proportion attracted to resistant females was 57% lower than the proportion attracted to susceptible females. In a flight tunnel, azinphos-methyl did not affect the ability of susceptible or resistant males to locate a source of pheromone gland extract. Likewise, in an apple orchard, the insecticide treatment had no effect on the ability of susceptible or resistant males to locate a source of synthetic pheromone. In a flight tunnel, there was no difference in the proportion of azinphos-methyl-treated susceptible and resistant males locating a source of pheromone gland extract; however, in the orchard, 39% fewer azinphos-methyl-treated resistant males located a source of synthetic pheromone than azinphos-methyl-treated susceptible males. A similar proportion of susceptible and resistant males that had not been treated with insecticide located a source of pheromone gland extract in the flight tunnel, but in the orchard, the proportion of resistant males not treated with azinphos-methyl that located the source of synthetic pheromone was 32% lower than the proportion of susceptible males not treated with this insecticide. The implications of the differences in the effect of sub-lethal residues of azinphos-methyl on the pheromone communication system of susceptible and resistant moths are discussed in relation to the theory of the development of insecticide resistance, the detection of resistance in feral populations of moths using sex pheromone-baited traps, and the control of moths using sex pheromone-mediated mating disruption.  相似文献   

8.
The efficacy of microencapsulated sprayable pheromone was evaluated at different application rates and intervals for mating disruption of the oriental fruit moth,Grapholita molesta (Busck), in apple orchards during 2002. The following treatments were arranged in a randomized complete block design with three replications: (i) a low rate of pheromone (6.2 g a.i. ha−1) applied at 14-day intervals, (ii) a medium rate of pheromone (12.4 g a.i. ha−1) applied at 28-day intervals, (iii) a high rate of pheromone (24.7 g a.i. ha−1) applied at 28- day intervals, and (iv) a non-pheromone control (insecticides only). The combination of a single insecticide application against first generationG. molesta at petal fall with one pheromone application each for the second, third and fourth generations at 12.4–24.7 g a.i. ha−1 successfully controlled low populations. Pheromone-treated blocks. had significantly lower trap catches than those in the insecticide-treated control blocks. Among pheromone treatments, significantly more moths were caught in the 6.2 g compared with the 12.4 and 24.7 g rates. Fruit damage was <1% at harvest and there were no significant differences among treatments. Low rate frequent applications of sprayable formulation appeared to be effective under low pest pressure but efficacy declined with increasing populations. Further studies are needed to demonstrate the effectiveness of this approach under higher pest pressure. http://www.phytoparasitica.org posting July 13, 2005.  相似文献   

9.
为明确草地贪夜蛾Spodoptera frugiperda入侵是否会对我国小麦生产造成较大影响,通过从文献及国家统计局、中国粮油信息网收集草地贪夜蛾在我国的为害及防治相关数据与小麦的种植面积、产量及价格等相关数据的基础上,利用随机模型@RISK分别预测其在不防治场景与防治场景下对我国小麦产业造成的潜在经济损失。结果显示,如果在草地贪夜蛾入侵我国后不进行防治场景下,其对小麦生产造成的潜在经济损失总量的90%置信区间为1 023.44亿~5 299.79亿元,此情景下草地贪夜蛾对小麦的为害率是影响我国小麦产业潜在经济损失最大的变量;而在草地贪夜蛾入侵后投入防治场景下,其对小麦生产造成的潜在经济损失总量的90%置信区间为109.24亿~631.66亿元,单位面积防治成本是影响我国小麦产业潜在经济损失的关键输入变量;可挽回的经济损失总量的90%置信区间为779.07亿~4 903.97亿元,对其影响最大的变量是草地贪夜蛾对小麦的为害率。表明在草地贪夜蛾入侵我国的现实条件下,应积极增强对草地贪夜蛾的防控力度,以降低其对我国小麦产业造成的潜在经济损失。  相似文献   

10.
草地贪夜蛾对玉米和烟草的偏好性研究   总被引:2,自引:0,他引:2  
自2019年初首先在云南省发现草地贪夜蛾入侵中国以来,该虫已对国家粮食安全构成严重威胁。草地贪夜蛾寄主范围广,主要喜食禾本科植物,同时也能为害多种双子叶植物。本研究以玉米和烟草为测试对象,比较研究了草地贪夜蛾在两种寄主上的产卵量及两种寄主植物对草地贪夜蛾生长发育的影响。结果表明,每个养虫笼中放入2对雌雄成虫,玉米植株上的卵块数量(17±2.65)块/笼显著多于烟草叶片上的卵块数量(3±1.73)块/笼,玉米上的幼虫数量(834.67±275.16)头/笼显著多于烟草上的幼虫数量(92±55.83)头/笼,表明草地贪夜蛾更喜欢选择玉米进行产卵和取食。烟草上草地贪夜蛾幼虫死亡率达92.53%±1.46%,但其能在烟草上产卵和存活。取食玉米籽粒的草地贪夜蛾幼虫发育历期、死亡率、体重、蛹重分别为(17.22±1.90)d、24.35%±8.13%、(0.261±0.112)g/头、(0.187±0.030)g/头,取食烟草叶片的草地贪夜蛾对应的参数分别为(26.80±1.89)d、85.49%±4.16%、(0.034±0.028)g/头、(0.131±0.028)g/头,表明取食烟草叶片的草地贪夜蛾幼虫发育历期显著延长,幼虫死亡率显著升高,幼虫体重和蛹重显著下降。与取食玉米籽粒的草地贪夜蛾相比,取食烟草叶片的个体适合度显著降低,但成虫配对后能够产卵并孵化出幼虫。与非嗜好寄主烟草相比,草地贪夜蛾取食嗜好寄主玉米表现出更高的适合度,其偏好选择玉米进行产卵和取食,但在烟草上也能完成生活史,种群密度大时存在为害烟草的潜在风险。  相似文献   

11.
草地贪夜蛾在海南省发生后,迅速扩散,为明确草地贪夜蛾在海南的发生规律,并制定防控策略,本文对2019年4月30日至2020年9月8日全省18个市县草地贪夜蛾幼虫田间发生密度和面积以及成虫灯诱和性诱数据进行了分析。初步得出以下结论,草地贪夜蛾在海南省主要为害的作物为玉米、莪术、高粱和甜高粱,以玉米为主。草地贪夜蛾幼虫不同季节在玉米田发生密度大小为秋季>夏季>冬季>春季,幼虫周发生面积大小为冬季>春季>夏季>秋季。根据性诱和灯诱的诱蛾高峰,初步判断在2月份有草地贪夜蛾成虫从泰国、老挝和越南迁入海南。4月中旬后蛾量迅速下降,玉米种植面积减少,预测草地贪夜蛾成虫在4月中旬后迁出海南。针对草地贪夜蛾在海南的发生规律,制定出了以冬春西南玉米主产区为重点的分时、分区、分重点的监测防控策略。  相似文献   

12.
大麦田草地贪夜蛾的发生为害及抽样技术   总被引:2,自引:0,他引:2  
草地贪夜蛾在中国可取食为害玉米、高粱、小麦等禾本科作物,但其在大麦田的发生为害情况尚不清楚。我们对云南省曲靖市马龙区处于苗期至分蘖期大麦田的调查结果表明,草地贪夜蛾的虫田率高达62.5%、大麦受害株率为9.33%~100%、虫口密度为1~46头/m2,其中1~3龄幼虫比例达98.6%,受害株率与虫口密度呈显著正相关。大多数草地贪夜蛾幼虫藏匿于大麦心叶为害,取食后叶片形成半透明薄膜窗孔,幼虫在大麦田呈聚集分布。基于空间分布型的研究结果,我们提出了大麦田草地贪夜蛾幼虫理论抽样模型。本研究表明草地贪夜蛾可对大麦生产构成严重威胁。研发的幼虫抽样方法为大麦田草地贪夜蛾幼虫种群调查提供了技术支撑。  相似文献   

13.
草地贪夜蛾对我国玉米产业的潜在经济损失评估   总被引:5,自引:0,他引:5  
草地贪夜蛾Spodoptera frugiperda,又称秋黏虫,起源于美洲。自2019年1月入侵我国云南以来,目前已扩散至我国25个省、市(区)。目前在我国发现的草地贪夜蛾主要为害玉米,本研究在收集了草地贪夜蛾的为害及防治情况,玉米的产量、面积、价格等相关数据的基础上,利用随机模型@RISK分别预测了其在防治与不防治场景下对我国玉米产业的潜在经济损失。结果表明,在不防治场景下,草地贪夜蛾对我国玉米的潜在经济损失总量的90%置信区间为375.68亿~3 283.45亿元,投入防治后可挽回的潜在经济损失90%置信区间为254.78亿~2 918.93亿元。因此,为保护我国玉米种植业的安全生产,应加强田间防治来降低其对我国玉米产业造成的潜在经济损失。  相似文献   

14.
田间调查表明,2019年1月草地贪夜蛾入侵云南省后,在德宏州4县市冬季甜玉米上均有发生为害,世代重叠严重。5月份以前主要为害冬季甜玉米,平均被害株率和百株虫量分别为4.55%和5.72头。成虫喜产卵于玉米心叶上部正面,1~6龄幼虫可取食为害玉米的生长点、叶片、雄穗和果穗。其中1~3龄幼虫具有聚集为害习性和趋嫩性,常取食幼嫩的心叶叶肉,4~6龄幼虫常啃食叶片和雄穗,咬断生长点,在心叶期和抽雄期形成典型被害状。心叶期和抽雄期玉米被害株率较高,且抽雄期被害株率显著高于苗期和灌浆期。  相似文献   

15.
The fall armyworm Spodoptera frugiperda is a lepidopteran pest that can damage and destroy a wide variety of crops. It is widely present in the Americans and has been invasive in Africa since 2016. Larvae of Sfrugiperda were found for the first time in four rural farms on maize plants (Zea mays) located in Tafas town (Dara’a Governorate, in the south‐west of Syria) in November 2020. Infested maize showed the typical damage symptoms caused by Sfrugiperda. Furthermore, morphological identification of larvae based on standard parameters of larvae confirmed the identity of the pest as fall armyworm. Considering the recent introduction of the pest into the EPPO region, it could be concluded that the pest probably entered Syria through natural spread (active flight and via wind currents) from Jordan, which borders Syria in the southern part and where the pest was found very recently.  相似文献   

16.
Push–pull involves intercropping of cereals with Desmodium as a “push” crop and planting Napier grass/Brachiaria as the “pull” crop at the border. The technology has been reported to effectively control stemborers, striga weed, and fall armyworm (FAW), and to improve soil nutrition, resulting in increased grain yield. This study evaluated the impact of stemborer and FAW management using this technology on incidence of maize ear rots and preharvest contamination of grains with aflatoxin and fumonisin in western Kenya. The study was conducted during three cropping seasons on maize grown under the push–pull system and as a monocrop. Incidence of stemborer and FAW damage was determined as percentage of damaged plants, while incidence of ear rots was determined as percentage of ears with symptoms. At harvest, fungi were isolated from kernels and aflatoxin and fumonisin were quantified using enzyme-linked immunosorbent assay. Stemborer and FAW damage was significantly (p = .001) reduced by over 50% under the push–pull system. There was also a significant (p < .001) reduction in the incidence of Fusarium verticillioides (60%) and Aspergillus flavus (86%), which was reflected in a reduced incidence of ear rots (50%) with the push–pull system (p = .001). Fumonisin in maize from push-pull farms was significantly (p = .048) reduced (39%) but the technology had no significant (> .05) effect on aflatoxin. The study showed that push–pull is an effective strategy for managing maize ear rots and fumonisins, and therefore could play a role in improving food safety among smallholder maize farmers in the region.  相似文献   

17.
Field trials were conducted in cabbage (Brassica oleracea var capitata), cauliflower (B oleracea var botrytis) and knol khol (B oleracea gongylodes) crops at two different locations in Karnataka State (India) to optimize the timing of insecticide applications to control the diamondback moth, Plutella xylostella, using sex pheromone traps. Our results indicate that applications of cartap hydrochloride as insecticide during a 12–24 h period after the pheromone traps had caught on average 8, 12 and 16 males per trap per night in cabbage, cauliflower and knol khol, respectively, were significantly more effective than regular insecticide sprays at 7, 9, 12 or 15 days after transplantation. This was demonstrated by estimation of the mean number of eggs and larvae per plant, the percentage of holes produced, as well as the marketable yield of the three crops at each location. A good correlation between the immature stages, infestation level, the estimated crop yield and the number of moths caught in pheromone traps was also found, indicating the usefulness of pheromone‐based monitoring traps to predict population densities of the pest. © 2001 Society of Chemical Industry  相似文献   

18.
草地贪夜蛾迁飞行为与监测技术研究进展   总被引:9,自引:0,他引:9  
草地贪夜蛾Spodoptera frugiperda原产于美洲的热带和亚热带地区,广泛分布于美洲大陆。2016年入侵到非洲,迅速蔓延到撒哈拉以南的整个区域。2018年入侵到印度。联合国粮农组织(FAO)发出警告,草地贪夜蛾很有可能从印度蔓延到东南亚及中国南部为主的亚洲地区。为掌握草地贪夜蛾在国外的发生与迁飞为害规律,加强我国对草地贪夜蛾的入侵控制和监测预警,本文综述了草地贪夜蛾在美国、加勒比海国家、墨西哥以及非洲国家的迁飞行为规律、性诱剂、灯光诱捕以及迁飞路径的分子鉴定等监测预警技术的研究进展,从而为我国植保人员对该虫的监测提供技术指导。针对草地贪夜蛾在世界范围内的迁飞规律和入侵特点,结合我国农作物种植结构以及气候特点,提出加强对草地贪夜蛾的监测与检疫的建议。  相似文献   

19.
草地贪夜蛾Spodoptera frugiperda自2019年1月入侵我国云南以来,快速蔓延为害,严重威胁我国的玉米生产和粮食安全。本研究基于云南省德宏州351份玉米农户调查数据,利用以直接经济损失和防治费用为基础的经济损失评估模型,估算了2019年草地贪夜蛾对德宏州玉米生产造成的经济损失,并分析了农户实际采用的防治措施。结果表明,2019年草地贪夜蛾对德宏州玉米生产造成的经济损失约为1 399.29万元,其中,玉米产量变化造成的直接经济损失约为366.51万元,农户防治投入增加和政府宣传、培训和防治等费用支出约为1 032.78万元。本研究不但为了解草地贪夜蛾对我国不同地区作物生产造成的经济损失提供例证,也为因地制宜地制定草地贪夜蛾防治策略提供科学依据。  相似文献   

20.
Abstract

Action thresholds (AT) as insecticide application decision tools were developed and tested against rice leaffolders Cnaphalocrocis medinalis (Guenée) and Marasmia patnalis Bradley (Lepidoptera: Pyralidae) in four sites and 68 crops over a 13-year period in the Philippines. Leaffolder damage levels were generally low with a mean over all sites and crops of 2 – 3% damaged leaves (DL) and 6 – 9% in a given site as a per-crop average based on weekly samplings, with highest incidence per field on a given sampling date of 48%DL. The damage incidence over a typical crop cycle formed a bell-shaped curve with maximum numbers in the late reproductive and early ripening stages. Continuous population buildup over the planting cycle did not occur in any one site over the season, thus a strategy of monitoring earlier planted fields to forewarn against impending economic damage had no basis. ATs were based on different levels of percentage DL, number of larvae per hill (L), and density of flushed moths. Collectively ATs were surpassed in 1, 12, and 4% of fields in each of the three main growth stages. A scoring system was based on benchmark criteria including both leaffolder damage and yield loss. The 15%DL threshold performed best in all growth stages, only equaled by 1L in the vegetative stage, scoring 93 – 99% correct decisions in each of the growth stages. Flushed moths produced the most false positive decisions and the lowest performance scores. The best insecticide response gave only a disappointing 53% control and therefore was a significant weakness in using AT technology. BPMC, endosulfan, and monocrotophos performed the best and azinphos-ethyl and Bt the least. Sites with the highest densities had the most rapid rise in damage levels, thus requiring more frequent monitoring. Low leaffolder damage levels were most likely due to the activity of natural enemies. Given the ability of high tillering varieties to compensate from pest damage, farmers would be better off embracing integrated crop management as a preventative measure to bolster inherent tolerance levels combined with crop monitoring based on historical population levels. In sites with a record of high damage levels, monitoring should start 4 weeks after transplanting (WT) on a weekly basis and more risk averse farmers may increase the interval to twice a week during flag leaf stage. In sites with lower observed levels, monitoring can begin 6 WT on a weekly basis and continue through the flag leaf stage. Significant yield increases were recorded with the best AT characters despite evidence of modern rices to tolerate high damage levels. Reasons for this apparent paradox are discussed.  相似文献   

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