中晚粳稻区褐飞虱防治策略的研究

为了解二代褐飞虱对粳稻的为害损失,确定合理的防治指标和防治策略,为科学使用噻嗪酮、吡虫啉等药剂防治稻飞虱提供依据,作者在武育粳３号上,通过接不同的虫量,并进行笼罩的方法,研究了二代褐飞虱的增殖规律和为害损失及防治指标。并进行了锐劲特防治不同世代褐飞虱策略试验。结果表明,不同水稻生育期,不同虫口密度的褐飞虱的增长速度不一样;在水稻同一生育期,低密度的增殖速度要大于高密度,但总虫量高密度区显著高于低密度区。二代褐飞虱百丛虫量与水稻产量损失呈极显著正相关（ ｒ＝ ０．９５７６**）,关系式为 ｙ＝－ １８．３３０２＋ １０． ２８９２ｌｇｘ（ｘ为 ８月上旬褐飞虱百丛虫量）,防治指标为 １１０－１２０头。因此,在早发年,迁入量较大的年份必须采取“治二压三控四”的策略,１９９６－１９９７年全面推广这一策略,成效显著。     

基因聚合改良杂交稻组合的稻飞虱田间抗性表现

褐飞虱Nilaparvata lugens(Stl)是杂交水稻的重要虫害,培育高抗褐飞虱的杂交水稻新组合被认为是目前防治飞虱最有效、经济的方法。本研究以分子标记辅助选择培育的抗褐飞虱杂交水稻为材料,通过苗期和成株期的全生育期田间抗性鉴定,对基因聚合改良杂交稻组合的褐飞虱抗性进行综合评价,结果表明,基因聚合改良杂交稻组合的苗期抗性介于抗和中抗水平,田间虫量在7次调查中均低于800头/百丛,远低于2000头/百丛的防治标准,而对照扬两优6号、两优培九和当地农家品种两优63在8月29日到9月10日飞虱发生高峰期的百丛虫量分别最高达到5400头、2030头和10700头,高于或远高于2000头/百丛的防治标准。改良组合川香29A/华恢1462的产量在通城比对照扬两优6号增产11.8%。上述结果表明抗褐飞虱改良杂交稻新组合能够有效抑制稻田褐飞虱种群数量,节约人工和农药成本,增加水稻产量。     

四种药剂防治稻飞虱的药效试验

<正> 稻飞虱(褐飞虱、白背飞虱、灰飞虱)是我县水稻上的头号害虫,1987、1988年连续二年在早稻上特大发生,一般百丛禾有虫4500～7000只,局部丘块虫口密度高达15000只/百丛。为     

褐飞虱越冬温度指标的研究

对褐飞虱各虫态和不同生育期水稻过冷却点的测定及在人工模拟低温条件下耐寒力的比较表明:褐飞虱各虫态的耐寒力明显高于水稻。证明在冬季低温降临后,水稻先行枯萎,褐飞虱在食料缺乏和低温的共同影响下相继死亡。 水稻生存的下限温度在0—-2℃间,可作为褐飞虱在我国越冬的温度指标。据此,对褐飞虱在我国大陆的越冬北界提出了讨论意见。     

广东稻区褐飞虱对烯啶虫胺和呋虫胺的敏感性测定

为了科学用药和抗性治理提供理论依据,在室内采用稻茎浸渍法测定了采自广东省广州、南雄、雷州、连州、海丰、怀集和大埔等7个地方田间褐飞虱种群对烯啶虫胺、呋虫胺的敏感性。试验结果表明:广东地区褐飞虱种群对烯啶虫胺的敏感性LC_(50)值为2.3187-7.1489mg/L,抗性倍数分别为4.93-15.21倍,南雄地区褐飞虱种群对烯啶虫胺仍处于敏感阶段;广州、海丰和雷州等3个地区褐飞虱对烯啶虫胺已产生低水平抗性,大埔、连州和怀集等3个地方褐飞虱已对烯啶虫胺产生中等水平抗性。广东地区褐飞虱种群对呋虫胺的敏感性LC_(50)值为3.6696-11.8093 mg/L,抗性倍数为26.21-84.35倍,表明广东省不同地区褐飞虱种群对呋虫胺均产生中等水平抗性。建议在防治褐飞虱时,对于低水平抗性的烯啶虫胺应轮用、混用,对中等水平抗性的呋虫胺应限制使用。     

浙北单季晚(粳)稻区稻飞虱发生特点与原因探讨

近年来 ,浙北单季晚 (粳 )稻区稻飞虱发生特点为 ,以白背飞虱Sogatellafurcifera (Horvath)和Ni laparvatalugens (St l)褐飞虱为优势种群 ;发生代次多 ,主害代为 3代白背飞虱和 5代褐飞虱 ,少数年份 4代褐飞虱也成为主害代 ;发生偏重 ,但地区和田块间不平衡性突出。其发生主要受外迁虫量、水稻栽增管理和品种特性、夏秋季气候条件和农药防治等因素影响     

湖北稻区褐飞虱田间种群对常用杀虫剂抗药性监测

【目的】明确目前褐飞虱Nilaparvata lugens田间种群对常用防治药剂的抗性现状,为制定褐飞虱的科学用药策略提供科学依据。【方法】于2009-2014年采用稻茎浸渍法监测了湖北褐飞虱武穴梅川、枣阳十里铺、孝感陈店、鄂州长港和武汉江夏稻田的褐飞虱田间种群对11种杀虫剂的敏感性。【结果】湖北稻区褐飞虱田间种群已对吡虫啉(抗性倍数RR=101.8~1 239.4)、噻嗪酮(RR=15.9~1 326.3)产生高水平抗性;对噻虫嗪(RR=24.9~146.5)产生中等水平至高水平抗性;对噻虫胺(RR=9.9~16.5)、呋虫胺(RR=13.5~15.9)、乙虫腈(RR=18.3~60.4)、毒死蜱(RR=17.4~29.8)、异丙威(RR=13.9~46.0)产生中等水平抗性;对啶虫脒(RR=5.1~9.9)产生低水平抗性;对噻虫啉(RR=3.9~7.1)处于敏感至低水平抗性水平;对醚菊酯(RR=1.3~4.9)处于敏感水平。此外,褐飞虱对噻虫嗪、噻嗪酮抗性上升明显,同时褐飞虱对吡虫啉抗性也有上升的趋势。【结论】仍需暂停吡虫啉、噻嗪酮在水稻上防治稻飞虱,严格限制吡蚜酮在水稻上的使用次数;醚菊酯可作为吡虫啉、噻嗪酮和吡蚜酮的替代药剂或轮换药剂。     

褐飞虱成虫不同密度和取食时长胁迫下水稻植株的生理生化响应

【目的】探索褐飞虱Nilaparvata lugens不同密度与取食时长胁迫下水稻植株生理生化响应。【方法】在褐飞虱成虫3个密度(2,4和8头/株)与4个取食时长(6, 24, 48和96 h)的组合处理后，应用生物化学分析方法检测水稻植株中叶绿素(chlorophyll, Chl)与总蛋白(total protein, TP)含量，脂氧合酶(lipoxygenase, LOX)、总超氧化物歧化酶(total superoxide dismutase, T-SOD)、过氧化物酶(peroxidase, POD)与多酚氧化酶(polyphenol oxidase, PPO)活性。【结果】与对照组(未接种褐飞虱成虫)相比，取食6 h时，低密度(2头/株)褐飞虱成虫引起水稻植株中Chl含量显著降低，TP含量和PPO活性显著升高；高密度(8头/株)褐飞虱成虫引起水稻植株中Chlb和总Chl含量、TP含量及LOX和POD活性显著升高。与对照组相比，取食24 h时，低密度褐飞虱成虫引起水稻植株中Chl含量和PPO活性显著降低，LOX, T-SOD和POD活性显著升高，高密度褐飞虱成虫引起水稻植株中...     

2007年广西早稻田褐飞虱发生动态及虫源分析

褐飞虱Nilaparvata lugens(Stal)是我国水稻上的重要害虫,近年来在全国连续大暴发,给我国水稻生产造成严重的损失。广西是境外虫源迁入我国的第一站,分析其早稻田褐飞虱的种群动态和迁飞规律,对全国褐飞虱的预测预报和防治工作意义重大。采用田间系统调查与雌虫卵巢系统解剖的方法研究了2007年南宁地区早稻田的褐飞虱发生动态和世代种群特征,分析全区灯诱数据确定迁入高峰期,并运用美国NOAA网站的HYSPLIT平台对2007年广西褐飞虱早期的6段迁入高峰期进行了数值模拟和虫源地分析。结果表明:(1)2007年广西南宁地区褐飞虱在晚熟品种田的发生虫量明显高于早熟品种田,发生、危害期明显延长,为我国北方其他稻区的褐飞虱的迁入积累了充足的虫源基数。(2)确定了南宁地区的早稻田褐飞虱各发生世代的虫源性质。第2代属于大部迁入型;第3代前期属于本地繁殖,部分迁入型,后期属部分迁出型;第4代属于大部分迁出型。(3)4月下旬-5月上旬,虫源地主要分布在越南、老挝中部的地区(18°-20°N);5月中下旬,虫源地主要分布在越南、老挝较北的地区(20°-22°N),部分来自我国海南省和雷州半岛;而6月上旬桂北地区大规模迁入的虫源地主要分布在越南东北部、广西西南部;低空急流为广西褐飞虱大规模迁入提供了运载气流,而当时的降雨是迫使褐飞虱集中降落的主要原因。     

“秕谷草-伪褐飞虱-中华淡翅盲蝽”载体植物系统的可行性

为明确用于防治稻飞虱的“秕谷草-伪褐飞虱-中华淡翅盲蝽”载体植物系统的可行性,本文开展了靶标作物水稻、载体植物秕谷草和靶标害虫褐飞虱、替代猎物伪褐飞虱组合对中华淡翅盲蝽成虫形态、种群增长参数、产卵选择性和取食选择性的影响研究.结果表明: 中华淡翅盲蝽水稻种群(取食褐飞虱卵)的雌雄成虫个体均显著大于秕谷草种群(取食伪褐飞虱卵).取食褐飞虱卵的中华淡翅盲蝽种群增长参数单雌产卵量、净增长率、内禀增长率、周限增长率明显高于取食伪褐飞虱卵的种群,但取食伪褐飞虱卵也有较高的种群增长能力,足以扩繁种群.对于靶标作物水稻和载体植物秕谷草,无论是水稻种群还是秕谷草种群均偏好在水稻上产卵.同时,2个种群的雌虫、雄虫和若虫对褐飞虱卵和伪褐飞虱卵捕食量没有显著性差异.在上述研究基础上,讨论了在田间建立“秕谷草-伪褐飞虱-中华淡翅盲蝽”载体植物系统的可行性.     

华北棉区第三代棉铃虫的经济阈值

1980—1982、1984—1985年在河北省饶阳县的不同土壤肥力水平、不同棉花品种上进行了模拟为害和自然为害试验,旨在确定第三代棉铃虫 Heliothis armigera(Hubner)虫口密度与棉花产量之间的关系.结果表明,棉花对于第三代棉铃虫为害的补偿能力较弱.较好的土壤肥力亦不能促使棉株完全补偿三代期间的受害损失.每亩皮棉减产斤数Y与第三代百株累计卵量E₃的关系为:Y=-0.2801+0.0643E₃.根据防治的直接收益与直接代价,算出了第三代棉铃虫的经济阈值为百株累计卵量35粒,这一阈值可适用于不同肥力水平的地块.     

Population Dynamics of Meloidogyne incognita and Rotylenchulus reniformis Alone and in Combination,and Their Effects on Sweet Potato

Meloidogyne incognita (Mi) and Rotylenchulus reniformis (Rr) interactions on sweet potato were studied in naturally and artificially infested field plots for 3 years. In a naturally infested field, early season counts of Mi or Rr were positively correlated with later counts of the same nematode, but negative correlations were found between early Mi and subsequent Rr, and early Rr and subsequent Mi counts. In field plots fumigated with methyl bromide and then infested with low levels of Rr, Mi, and Rr + Mi, final population densities of Mi juveniles were reduced by Rr, but Rr was not affected by Mi. In field plots with a high natural population density of Rr, artificial infestation with high levels of Mi in both fumigated and nonfumigated treatments inhibited Rr, while the final Mi juvenile population density was not affected. Results indicate that a competitive interaction exists with each species capable of inhibiting the other and becoming the dominant population. The nematodes had no apparent effect on yield at the inoculum densities used, either alone or mixed. Both nematodes increased cracking of sweet potatoes, but mixed populations did not differ in incidence of cracking from either Rr or Mi alone.     

Spatial patterns and infestation processes in the horse chestnut leafminer Cameraria ohridella: a tale of two cities

Spatial patterns of the horse chestnut leafminer Cameraria ohridella Deschka & Dimic (Lepidoptera: Gracillariidae) population density was analysed in the cities of Bern and Brussels in order to explore its spatial population dynamics. The surveys were carried out in Bern in 1998 and 2000 and in Brussels in 2001 to assess population density in relation to local characteristics. In Brussels, population density was also measured using pheromone traps distributed over the city and collected twice per moth generation. A quantitative relationship was found between local population density (measured by pheromone traps and survey observations) and the amount of leaves left on the ground the previous fall. Several other factors were related to observed infestation levels: the occurrence of the pathogen Guignardia aesculi was inversely related to infestation by C. ohridella in Bern in 1998 and 2000, the number of horse chestnut trees within 800 m distance was positively related to infestation level in Bern in 2000, and the proportion of green areas within 100 m and the number of other horse chestnut trees within 2000 m were positively related to infestation levels in the 2001 Brussels survey. The pattern of infestation levels as a function of distance to potential population reservoirs suggested that C. ohridella re‐invades areas where overwintering leaves have been cleaned from refuge areas such as parks or urban forests. Our results indicate that the removal of leaves is a feasible first aid control measure to reduce moth population densities. However, leaf removal may not reduce moth densities when done improperly. In places where proper leaf removal is not feasible, other control measures are needed.     

华北棉区第二代棉铃虫的经济阈值

1980—1983年在河北省饶阳县及安徽省濉溪县的不同的土壤肥力类型、不同的棉花品种和不同的栽培管理条件下进行了模拟为害和自然为害的试验,旨在确定第二代棉铃虫Heliothis armigera(Hübner)数量与棉花Gossypium hirsutum L.产量和质量的关系。试验结果表明,棉花对于第二代棉铃虫为害的补偿力很强,这种补偿力随着土壤肥力的提高而增强。棉花品种、年份以及栽培管理方法对补偿力的影响属于次要。通过组建的一个静态模型,收进了二代棉铃虫防治的直接收益与代价以及间接收益与代价,算得高、低肥力地的第二代经济阈值,百株累计卵量分别为332粒和34粒。产量水平在80—90斤的中等偏低肥力地,其阈值可定为60粒。     

Determining an economic injury level for the persea mite,Oligonychus perseae,a new pest of avocado in Israel

The persea mite, Oligonychus perseae Tuttle, Baker & Abbatiello (Acari: Tetranychidae), a pest of avocado, was first discovered in Israel in the autumn of 2001. It has since spread to most avocado growing areas in Israel. To establish an economic injury level (EIL), based on the percentage of leaf area damaged (PLAD), we conducted an extensive field study. For three consecutive seasons we created distinct pest infestation levels on the Hass avocado cv., by applying acaricides (spirodiclofen and abamectin) at 50, 100, and 250 mites per leaf levels, along with non‐sprayed controls in a replicated block design. At harvest time we evaluated the level of leaf damage and fruit yields across treatments. In two out of the 3 years, trees sprayed at 50 and 100 mites per leaf levels had similar PLAD values, differing from trees treated at the 250 mites per leaf level and the non‐treated control, the latter pair also being similar. Over the 3 years, mean yield attained at the two higher infestation levels was reduced by 20% in comparison to the mean yields recorded for plots sprayed at the lower thresholds. Accordingly, we suggest that scouts adopt an action threshold (AT) of 50–100 mites per leaf. Future research is needed to refine this AT. Mean annual cumulative mite days (CMDs) of the two higher levels was ca. 13500 ± 700 per leaf. Using the linear regression equation PLAD = 0.0009CMDs + 2.42, describing leaf damage as a function of CMDs, we estimated an EIL of ca. 15 PLAD.     

Spatial Analysis of Heterodera glycines Populations in Field Plots

Spatial heterogeneity in nematode population densities presents an obstacle to the precise determination of infestation levels. Three field plots were intensively sampled for soybean cyst nematode (Heterodera glycines Ich.) cysts before and after spring cultivation to quantify the spatial attributes of the population. Population density strata were detected running parallel to plant rows. Highest population densities before cultivation were found in the plant row and the middle furrow, Population density in the plant row averaged 26% higher and 4% lower than the whole-plot mean before and after cultivation, respectively. Cysts containing fewer than 25 eggs were not stratified, indicating that most were produced before the previous season. Sample population counts were fit to the negative binomial distribution model before cultivation, but distributions differed among plots. The Neyman type A and negative binomial distributions both fit the data after cultivation disturbed the soil. Population clusters 1-3 m long were detected in plant beds before cultivation. Heterogeneity in population density increased with plant row length after cultivation. Optimum plot length for minimal spatial heterogeneity in four-row mechanically tended field plots was estimated at 6 m after trimming plot ends.     

Economic injury levels for western flower thrips (Thysanoptera: Thripidae) on greenhouse cucumber

Low, medium and high densities of western flower thrips, Frankliniella occidentalis (Pergande), were established in three greenhouses at the Greenhouse and Processing Crops Research Centre, Ontario, Canada, in 1996 and 1998 to develop economic injury levels for thrips on greenhouse cucumber. Thrips densities were monitored weekly using yellow sticky traps and flower counts. Fruit was harvested twice a week, graded for size, weighed, and rated for thrips damage using three damage categories. Significant yield reduction was detected 4 wk after severe fruit damage was observed in the high and medium thrips density treatments in 1996 and 7 wk in 1998. Percentage of severe damaged fruit (P(F3)) has significant linear relationships with the adult thrips density (x) that was sampled by sticky traps 1 wk before harvest (P(F3) = -0.2533 + 0.0828x) and that was sampled by flower counts 2 wk before harvest (P(F3) = -0.2025 + 0.5490x). Based on the regression equations, economic injury levels, expressed as adult thrips per sticky trap per day or adult thrips per flower, were calculated for various combinations of control costs, yield potential and fruit prices. The economic injury levels for F. occidentalis ranged from 20 to 50 adults per sticky trap per day or 3 to 7.5 per flower as determined under average greenhouse production conditions in Ontario, Canada.     

Sequential sampling plans for western flower thrips (Thysanoptera: Thripidae) on greenhouse cucumbers

The development of cost-effective and reliable sampling programs for the management of western flower thrips, Frankliniella occidentalis (Pergande), on greenhouse cucumbers is important for getting growers to adopt economic injury levels and economic thresholds. The objectives of this study were to develop two sequential sampling plans. A fixed-precision sequential sampling plan was designed for estimating F. occidentalis adult density at a fixed-precision level on cucumber flowers. Also, a sequential sampling plan for classifying thrips population levels as below or above economic thresholds was developed to assist in decision making for the timing of pesticide applications. Both sequential sampling plans were validated using a resampling simulation technique on nine independent data sets ranging in density from 1.25 to 12.95 adults per flower. With the fixed-precision sampling plan, average means obtained in 100 repeated simulation runs were within the 95% CI of the estimated mean for all data sets. Appropriate levels of precision for the different population densities were recommended based on the simulation results. With sequential sampling for classifying the population levels of thrips in terms of an economic threshold, it has the advantage of requiring smaller sample sizes to determine the population status when the population densities differ greatly from the critical density (i.e., economic threshold). However, this plan needs a great number of samples when population density is close to the critical density. In this case, use of a combination of both sampling plans is recommended.     

Economic thresholds for Aphis gossypii (Hemiptera: Aphididae) on Citrus clementina

Different levels of Aphis gossypii Glover were maintained on clementine trees by means of isolation inside mesh cages. Clementine yield loss was correlated with the number of aphids per square meter of canopy, obtaining the corresponding formula. Starting from this formula, the economic injury level (EIL) was calculated as follows: [218,333C + 11,130.6 VP0K]/[57.08 VP0K - 100C] = EIL (aphids/m2), where C = total insecticide cost per hectare, V = fruit price per kilogram, P0 = yield per hectare of a minimum pest level orchard, and K = reduction of injury due to treatment. Starting from the EIL, the economic threshold, the environmental EIL, and the environmental economic threshold were obtained. Formulae relating the number of aphids per square meter with other simpler indices expressing these thresholds (percentage of infested shoots, infested shoots per 0.25 m2 ring, index of infestation, percentage of occupied rings, and number of weekly captured aphids in a yellow trap) also were calculated.     

种群密度与施肥对垂穗披碱草刈割后补偿作用的影响

 以甘南亚高山草甸常见牧草垂穗披碱草(Elymus nutans)为对象,通过考察种群密度、施肥与刈割处理等对植物生长和生殖的影响效应,比较了垂穗披碱草在5个密度及2个施肥实验处理条件下对4种刈割处理的补偿性反应特点。结果表明,在所有密度及施肥处理条件下,早期轻度刈割处理 (分蘖期刈割,留茬4 cm) 都有利于植物的补偿作用,后期重度处理 (拔节期刈割,留茬2 cm) 可显著降低植物的地上部分生物量及生殖部分干重 (穗重)。在不施肥情况下,刈割对垂穗披碱草的影响程度随种群密度而加大,在低密度处理中早期轻度刈割的植物发生了超补偿。可以认为,低密度种群中植物具有较多的分蘖是植物在刈割后表现出较高补偿能力的一个重要生物学原因。实验还发现,施肥可提高植物个体的分蘖能力和秆叶再生能力,因而总体上可增强植物的补偿能力,并且在中等密度条件下垂穗披碱草的补偿能力较强,尽管没有发生超补偿现象。不过,施肥主要是有利于植物地上营养器官的补偿,生殖器官的补偿程度较小一些。试验结果对科学管理人工草场具有一定的指导意义。