冬季亚麻杂草种类危害及防除研究

本文调查研究了州内亚麻种植地区的田块杂草种类、分布和发生规律。查清杂草共有101种，隶属25科，发生危害重的有7科26种，占25．74％；双子叶杂草77种，占76．23％，单子叶杂草22种，占21．78％，蕨类杂草2种，占1．98％。一年生杂草42种，占42．58％，越年或一年生杂草29种，占28．7l％，多年生杂草30种，占29．7l％。杂草随亚麻的播种而生长，至枞形期达最高峰，88—1231株／m^2。防治上在亚麻枞形期（株高5—10cm）、杂草2—3叶期选择50％敌草隆＋5％精喹禾灵或50％敌草隆＋56％二甲四氯钠盐，兑水喷雾，防除效果达90％以上。     

移栽棉田化学除草技术

移栽棉田化学除草技术韩学俭（陕西省农科院植保所７１２１００）棉田杂草有８１种，分属２８科。其中分布面广，发生量大的杂草有４０种左右。马唐是棉田主要恶性杂草，其发生量占棉田杂草总量的３４．７％～７５．４％。其次为旱稗、牛筋草、狗尾草等。棉田常见还有鳢肠...     

菏泽地区棉田杂草调查初报

运用倒置“W”9点取样法,对菏泽地区棉田杂草调查结果表明,该地区棉田杂草有12科26种,其中禾本科杂草占30．8％,阔叶杂草占61.5％,莎草科占7．7％。相对多度10以上的杂草依次有马齿苋、牛筋草、马唐、铁苋菜、碎米莎草、反枝苋、香附子等7种,其中,马齿苋、牛筋草、马唐、铁苋菜4种杂草的相对多度分别为55．12、51．84、45．7、35．37,是当地棉田杂草的优势种。     

黑龙江省北部大豆田杂草调查

采用与传统的五点取样法不同的倒置“Ｗ”９点采样法,对黑龙江省北部豆麦轮作区大豆田杂草发生危害情况进行了调查。结果表明,该地区大豆田杂草有１７科４１种。其中阔叶杂草１４科３５种,占８５．４％,禾本科４种占９．８％,鸭跖草科１种,木贼科１种,种占２．４％。相对多度达１０以上的杂草依次为,稗草、鸭跖草、间荆、铁苋菜、香薷、反枝苋、藜、卷茎蓼、苍耳等９种。其中前７种相对多度达２０以上,可视为当地大豆田的优势杂草。     

漳州市农田杂草种类,组合（群落）及为害的调查报告

一、粮油作物杂草种类、组合及为害1、小麦杂草我市小麦主要杂草有13科21种，其中以酸模叶蓼、看麦娘、碎米荠、繁缕、小藜、鳢肠为主要杂草。恶性杂草以酸模叶蓼和看麦娘为主，最高为害级为三级，为客指数27、6和26.7。频度在90％-100％，密度以看麦娘最高，每平方尺38．8株．常见杂草组合为：看麦娘-酸模叶蓼-小藜，或酸模叶蓼-看麦娘-鳢肠（或碎米荠）。2、水稻杂草早稻主要杂草有19种，分属13科，主要种类有稗草、异型莎草、空心莲子草、鸭舌草、矮慈菇。四字草、节节莱。其中以种草、空心莲于草为恶性杂草，为害指数在8—26．7。典型杂…     

冬季亚麻杂草种类危害及防除研究

本文调查研究了州内亚麻种植地区的田块杂草种类、分布和发生规律.查清杂草共有101种,隶属25科,发生危害重的有7科26种,占25.74%;双子叶杂草77种,占76.23%,单子叶杂草22种,占21.78%,蕨类杂草2种,占1.98%.一年生杂草42种,占42.58%,越年或一年生杂草29种,占28.71%,多年生杂草30种,占29.71%.杂草随亚麻的播种而生长,至枞形期达最高峰,88-1231株/m2.防治上在亚麻枞形期(株高5-10cm)、杂草2-3叶期选择50%敌草隆+5%精喹禾灵或50%敌草隆+56%二甲四氯钠盐,兑水喷雾,防除效果达90%以上.     

实施稻田无草害工程 促进水稻生产持续发展

（一）稻田草容与化学除草现状水稻是浙江省的主要粮食作物，每年播种面积213．3万公顷左右。近年来，随着抛秧、直播等轻型栽培技术的推广，稻田草害趋于严重，不利于水稻生产发展。据调查，全省稻田杂草有42科155种，其中造成！级危害的面积占种植面积的46％，一般因草害而造成的产量损失占10％～30％，严重田块达30％以上。又据近10年统计，浙江省粮食作物因遭受病虫草鼠危害，经防治后每年仍要损失9亿公斤，约占粮食总产量的6％，其中因草害而引起的损失要占1／3左右。近几年，浙江省稻田化学除草工作发展较快，技术普及率约占稻田面积…     

新疆兵团主要植棉区机采棉田杂草调查

采用倒置“W”九点取样法对新疆兵团北疆、东疆主要植棉师蕾期、铃期棉田杂草进行调查。结果表明：北疆第六师、东疆第十三师机采棉田杂草主要有16科31种，其中禾本科杂草占16.1%，阔叶杂草占80.7%，莎草科杂草占3.2%；1年生杂草占64.5%，多年生杂草占35.5%。北疆第六师蕾期棉田优势杂草为龙葵、野西瓜苗、田旋花、灰藜，铃期优势杂草为龙葵、田旋花、灰藜。东疆第十三师蕾期棉田优势杂草为灰藜、反枝苋、狗尾草，铃期优势杂草为龙葵、灰藜、反枝苋、田旋花。不同地区、不同生育时期棉田优势杂草有所差异。研究结果将为新疆兵团机采棉田杂草的科学可持续防控提供重要依据。     

龙门县农田草害种群组成危害程度及防除策略

通过调查发现，龙门县水稻杂草有15科40种，柑桔杂草有16科53种，花生杂草有8科30种，蔬菜杂草有12科35种。危害水稻的优势种是四叶萍，亚优势种是鸭舌草和黑藻；危害柑桔的优势种是马兰和马唐，亚优势种是狗尾草和狗牙根；危害蔬菜、花生的优势种因海拔、生态环境不同差异较大。根据调查结果，对农田草害造成的粮油损失进行估算，并提出了针对性的防除策略。     

华南地区大豆田杂草种子库特征与化学防除的研究

针对华南地区大豆田杂草防除问题,采用种子库诱萌法和田间药效试验法,研究田间杂草种子库的预测方法,筛选最佳化学防除方案.结果表明:杂草种子库共有杂草7科10属,主要分布在0～ 10 cm的土层,总出草量为6 861株·m-2.田间实际出草种类为6科9属,实际出草量平均为208株·m-2,占土壤杂草种子库总量的3.03％;6种除草剂都具有良好的防除效果,其中7.5％禾阔灵乳油的防除效果最佳,能有效防除禾本科杂草、莎草科杂草以及阔叶杂草,药后45 d鲜重防效仍达到70.7％～72.4％,可使大豆增产20.5％～ 34.5％.     

3种喷雾助剂对东北春大豆除草剂减量增效的影响

为降低除草剂使用量,提高东北春大豆杂草防除效果,在常用土壤封闭处理剂和茎叶处理剂减量25%的基础上,分别添加3种喷雾助剂(有机硅类助剂施倍丰、表面活性剂类助剂激健、植物油类助剂速捷),比较杂草防除效果和大豆生物学性状、产量、收益等指标,探明3种助剂对除草剂减量的作用影响。结果表明:3种喷雾助剂对杂草总防效优异,鲜重防效、株防效均高达90%,添加3种喷雾助剂的减药处理与常规不减药处理比较没有显著差异。施倍丰对禾本科杂草、阔叶杂草的防效最好,对2类杂草的最高鲜重防效和最高株防效均达到90%以上;速捷对禾本科杂草的鲜重防效最高,达94.2%,但株防效最低,为86.7%,对阔叶类杂草的鲜重防效和株防效约为86%;激健对禾本科杂草防效与施倍丰相当,株防效和鲜重防效约为90%,激健对阔叶类杂草的鲜重防效和株防效比速捷略低,防效约85%。3种喷雾助剂对大豆株高、荚数、百粒重等生物学性状及产量、收益与常规不减药处理比较没有显著差异。激健对产量的影响最大,能增产4.47%,增效3.43%,其次是施倍丰,增产1.6%,增效2.12%,速捷没有增产增效作用。结果表明除草剂使用中添加喷雾助剂能达到减量增效的作用,本研究结果可以为推广除草剂减施技术提供方法参考。     

不同耕作模式对玉米田杂草发生规律的影响

在免耕、旋耕和翻耕玉米田试验区调查杂草种类和出苗数量,并在玉米生长中后期调查杂草种类、株数和鲜重。结果表明,不同耕作模式玉米田杂草发生规律有明显差异。免耕、旋耕和翻耕玉米田禾本科杂草高峰期都在播种后5周发生;阔叶杂草发生高峰期不同,免耕田为播种后1周,旋耕和翻耕田均在播种后2周。杂草种类不同,玉米生长中后期,免耕田有8种杂草,旋耕田有10种,翻耕田有12种;杂草发生总量不同,免耕田杂草总量最多,旋耕田居中,翻耕田最少;杂草单株鲜重不同,免耕田杂草单株鲜重最低,旋耕田居中,翻耕田最高。     

Comparative overwintering host range of three Adelphocoris species (Hemiptera: Miridae) in northern China

In northern China, Adelphocoris suturalis, Adelphocoris lineolatus and Adelphocoris fasciaticollis (Hemiptera: Miridae) are common pests of cotton and several other crops. These species have vastly diverse geographic distribution, seasonal dynamics and abundance, the underlying causal factors of which are poorly understood. In this study, the importance of a broad range of plant species as overwintering hosts for each Adelphocoris sp. was compared. Nymphal emergence from a total of 126 plant species was monitored at two distinct locations. The eggs of A. suturalis successfully eclosed from un-plowed cotton field soil and 115 plant species, primarily pastures, weeds and agricultural crops. The eggs of A. lineolatus successfully eclosed from 40 plant species, mainly pastures and weeds. Finally, A. fasciaticollis overwintered on 35 plant species, primarily tree species, weeds and agricultural crops. In conclusion, the most common and widely distributed mirid species, A. suturalis, overwintered on a comparatively broader range of plants compared to the other two species. These observations help to understand the differences in geographical distribution and abundance of the three Adelphocoris species, and constitute the basis for forecasting and pest management protocols for Adelphocoris spp. in China.     

普洱市小粒咖啡病虫害种类调查分析

对云南省普洱市小粒咖啡主要栽种区病虫害及荫蔽树种类、杂草和荫蔽树与咖啡病虫害的关系进行调查研究。结果发现普洱市小粒咖啡害虫有13种,病害有7种,常用荫蔽树有17种。文中还分析杂草和荫蔽树与咖啡病虫害关系,就普洱市咖农的管理技术提出建议。     

河口低热河谷区辣木林四季杂草调查研究

对河口低热河谷区辣木林四季杂草种类、群落组成进行调查。结果表明,该辣木林有杂草73种,隶属22科65属,其中外来入侵种19种,占杂草总数的26.0%。通过分析四季主要杂草的优势度得出,春、夏、秋季优势杂草主要是菊科的鬼针草(Bidens pilosa),禾本科的马唐(Digitaria sanguinalis)、十字马唐(Digitaria cruciata)、光头稗(Echinochloa colona)、牛筋草(Eleusine indica)等组成;冬季优势杂草主要有菊科的鬼针草、小飞蓬(Conyza canadensis)、鼠麴草(Gnaphalium affine)、野茼蒿(Gnaphalium affine)组成。其中,鬼针草为常年优势杂草,在四季杂草组成中外来入侵杂草优势明显。     

Potential allelopathic influence of certain pasture weeds

Laboratory and growth chamber research was conducted to determine the potential allelopathy of tissue harvested from certain weeds commonly found in pastures. Results of bioassays indicated that the weeds dogfennel and mayweed chamomile are potentially allelopathic to alfalfa and Italian ryegrass seedlings. Leaf-tissue extracts from the two weed species reduced seedling growth more than stem and root extracts. In most experiments alfalfa seedlings were influenced more than Italian ryegrass seedlings and seedling growth was influenced more than seed germination. Leaf tissue from the weed species mixed into potting soil at a concentration as low as 0.25% (w/w) significantly reduced alfalfa and Italian ryegrass plant development and foliage production. Extract and tissue concentration used in this research were estimated to be similar to concentrations expected to occur within the pasture ecosystem and below concentrations that would result in hypertonicity in the bioassays.     

Distribution of tobacco rattle virus and potato virus X in leaves,roots, and fruits and/or seeds of naturally-infected weeds

Weeds in tobacco rattle virus (TRV)-infested potato fields were examined for TRV and potato virus X (PVX) with the enzyme-linked immunosorbent assay. Questionable positive reactions were evaluated with immunosorbent electron microscopy. Of 615 weeds, representing 28 species, sampled over a two-year period, four species contained only TRV, three were infected only with PVX and eight had both viruses. Tobacco rattle virus was located only in the roots of five species and PVX was found only in the foliage of five species. Seeds and/or fruits of three species contained TRV while two contained PVX. Only one weed species,Solanum sara choides, contained both viruses in all plant portions tested. Potato virus X was not detected in weeds within a field planted with PVX-free potato seed.     

Shade reduces growth and seed production of Echinochloa colona,Echinochloa crus-galli,and Echinochloa glabrescens

Echinochloa species are problematic weed species in direct-seeded rice systems in Asia. Because of concern about the continuous use of single herbicides, cultural weed management strategies need to be developed to maintain the sustainability of direct-seeded rice systems. However, the design of such strategies requires an understanding of the differential responses of weeds to shade caused by crop interference. The effects of shade on growth and seed production of Echinochloa colona, Echinochloa crus-galli, and Echinochloa glabrescens were determined. Weeds of three Echinochloa species were grown continuously in full sunlight or in 50% or 25% of full sunlight, or started in full sunlight and transferred to 50% or 25% of full sunlight at 21 days after sowing. The results suggested that changes in shade regime did not affect the plant height of E. colona and E. glabrescens; however, shade reduced the height of E. crus-galli. Compared with the plants grown in full sunlight, 75% of continuous shade reduced E. crus-galli height by 22%. Shade reduced leaf, total shoot, and root biomass and seed production in all the weed species, if occurred during the early growth of the weeds. The weeds responded with increased leaf biomass ratio when grown in shade. Compared with full sunlight, continuous shade of 75% increased leaf biomass ratio by 90% in E. colona and this value was 25% in the other two species. The results of this study show that shade can reduce weed growth and seed production of Echinochloa species but it should not be considered as a stand-alone strategy to manage these weeds in rice. This highlights the need for the integration of other weed management strategies to achieve complete control of these species.     

Weed Allelopathy,Its Ecological Impacts and Future Prospects

Summary

The importance, characteristics, positive and negative impacts, and future role of weeds as an integral part of the natural and agroecosystems are evaluated and discussed. Interference between plants in nature and the importance of differentiating between competition and allelopathy are interpreted. Allelopathy as one component of weed/crop interference, allelochemicals from weed species and their possible mechanism of action are listed and discussed. Weed species with inhibitory action against cultivated crops, other weed species, and plant pathogens, as well as self-inhibitory (autopathic) species are reviewed. Stimulatory or inhibitory allelopathic effects of different crop plants, trapping and catching species, and the potential of allelopathic weeds in inhibiting or stimulating certain parasitic weed species are discussed and evaluated. Allelopathy as a mechanism and future strategy for agricultural pest control and farm management and the potential use and development of some allelochemicals as natural pesticides or plant growth regulators are also considered and discussed.     

除草剂混配施用对棉田常见杂草的防除效果

为了检验除草剂防除棉田杂草效果,以三氟啶磺隆、嘧草硫醚和精喹禾灵之间不同剂量的混配施用.试验表明：三氟啶磺隆和精喹禾灵两种混用及三氟啶磺隆、嘧草硫醚和精喹禾灵3种混用均对棉田杂草都有较好的防除效果.施药后7天杂草表现药害症状.施药后20天,三氟啶磺隆与精喹禾灵两种除草剂混用,随着三氟啶磺隆用量的增加对禾本科杂草的防效由89.2％增加到95.3％,对阔叶类杂草的防效由86.3％增加到94.9％,总体株防效由87.8％增加到95.2％;三氟啶磺隆与精喹禾灵、嘧草硫醚混剂3种除草剂混用,在精喹禾灵用量相同的条件下,增加三氟啶磺隆或嘧草硫醚的用量,对禾本科杂草、阔叶类杂草、杂草总体株防效均提高.施药后40天的株防效和鲜重防效均80％以上,说明混配药剂的持效期较长.