麻黄田杂草种类调查及防除

经过4年对麻黄田杂草种类调查明确,在甘肃麻黄田常见杂草有39种,隶属于18个科,赖草、画眉草、蓄、荠菜、独行菜、反枝苋、狗尾草和藜最为常见。5月上旬至6月下旬为杂草发生高峰期。可通过药剂土壤处理、茎叶喷雾防治和人工拔除控制麻黄田杂草。     

中藏药田草害调查及防除对策

3年中藏药田杂草调查结果表明,青海中藏药田杂草有100多种,其中野燕麦、旱雀麦、早熟禾等禾本科杂草和扁蓄、委陵菜、野艾蒿、藜等阔叶杂草最为常见。4月下旬至6月下旬为杂草发生高峰期。可通过药剂土壤处理、茎叶喷施防治和人工除草控制中藏药田杂草。     

黑龙江垦区杂草稻分布与发生

近几年黑龙江省农垦地区寒地水稻移栽面积迅速扩大,至2008年已经超过100万hm^2,化学除草面积覆盖率达到100％。但杂草稻由于与水稻生物学特性相近,药剂难以防除,危害面积越来越大。杂草稻有长芒、短芒和无芒,多为长芒。芒色有红色和白色两种,数量相当。种皮颜色有黑色、褐色、赤褐色、黄色,多为赤褐色。叶色有绿色和褐色,多为绿色。杂草稻在1—3cm水层下出苗率高于栽培稻。杂草稻具有较强的越冬能力。     

安徽省广德县油菜田杂草发生规律及危害现状调查

油菜播后7～10 d即可见草,禾本科杂草出草速度较阔叶草快而整齐,禾本科杂草出土高峰期在10月中旬至11月初,阔叶杂草在10月下旬至11月上旬。经化除后老鹳草取代稻槎菜上升为主要阔叶类杂草。     

麦田冬前除草注意“三要”

1、时间要适当。10月下旬到11月中旬是冬小麦田杂草的出苗高峰期,出苗数占总数的95％以上,翌年3月下旬到4月中旬,还有少量杂草出苗。冬前杂草处于幼苗期,植株小,组织幼嫩,对药剂敏感,是防除的有利时机。喷药应选择天气晴朗、无风,日平均气温在10℃以上时喷药;     

湖南省棉田杂草调查

对湖南省棉花主产区棉田杂草的种类、发生规律及化学除草情况进行了调查。结果发现, 湖南省棉田常见杂草包括12科, 28种, 其中禾本科杂草占25.00%, 阔叶杂草占67.86%, 莎草科占7.14%; 一年生杂草占78.57%, 多年生杂草占21.43%。相对多度10%以上的杂草有7种, 其中马唐、牛筋草、千金子、铁苋菜、小飞蓬5种杂草为湖南省棉田杂草的优势种, 相对多度分别为37.79%、33.64%、29.15%、26.23%、23.83%。杂草发生呈现3个高峰期, 分别为5月下旬, 6月中下旬, 7月下旬至8月初, 杂草防除主要采用苗前土壤处理和苗后茎叶处理相结合的化学防除方法。     

山东省麦田杂草发生及其化学防除策略研究

经79个代表性县、市调查,山东省麦田杂草主要有22种,隶属13科,21属。其中以十字花科、石竹科、紫草科、藜科杂草发生危害普遍。各农区麦田杂草种类、优势种组合及区域分布特点有一定的差异。总的趋势是由南向北随纬度的推移,耐湿的杂草渐减,耐寒、抗旱杂草增多;由渤海农区向湖东农区推移,耐盐碱杂草递减,喜肥湿杂草渐多。冬麦田杂草有秋、春两个发生高峰期,以春季发生数量大,危害重。化学防除适期以冬小麦返青至拔节期为宜。化防药剂除继续推广2,4-D丁酯外,高效、低毒、安全性好的新一代除草剂阔叶散、阔叶净、甲黄隆等可在我省大面积推广。     

棉田几种除草剂的使用技术与经济效益

一、棉田杂草种类及危害 喀什地区棉田,主要杂草有芦苇、稗草、狗尾草、灰黎、田旋花、苍耳、苦苣菜、苦豆子、草木栖及辣酱草等。稗草和灰黎在棉田出土危害有两个高峰期:第一个高峰期为4月下旬至5月中旬;第二个高峰期在6月底至7月下旬。芦苇出土危害一般在4月底至秋后。棉田杂草对棉花的生长、发育、产量及经济品质危     

贵州地区冷季型草坪中杂草的发生特点及综合治理技术

1997－2000年调查了贵州地区冷季型草坪中杂草的种类及危害。定期调查草坪杂草发生消长状况表明,贵州地区冷季型草坪杂草发生了2个高峰期,每个高峰期都有占绝对优势的杂草品种,提出了综合防治措施。     

夏季果园除草妙法

夏季是杂草发生的高峰期,此时由于雨水多,气温高,有利于杂草的发生.果园杂草主要种类有香附子、白茅、鸭跖草、莲子草、牛筋草等.     

A model of the cost of delay in spraying weeds in cereals

Using a previous model as a base, data derived in field trials in wheat ( Triticum aestivuort L.) and bailey ( Hordeum vulgare L.) were assessed to estimate the yield penalty, and resulting reduction in economic benefit, from progressive spraying of herbicides up to late crop tillering. Compared with early post-emergence application, yield penalties from delayed spraying began at early tillering. For median values of weed-free yield and weed density in the data set. the loss in potential yield increase when spraying at late tillering compared with early post-emergence was 71%, Crops with higher weed-free yield potential and with greater initial weed density showed a proportionately (as well as absolutely) larger yield penalty from a moderate delay in spraying, indicating an earlier and more intense onset of competition with weeds.     

Weed competition in spring-planted strawberries

Annual weeds germinating after planting strawberry (Fragaria chiloensis (L.) Duch. cv. Cambridge Favourite) in late March had no effect on crop growth if removed by late May. Dense weed cover thereafter severely inhibited stolon growth, virtually eliminating it if allowed to remain beyond mid-August. Shading by weeds inhibited leaf production and caused etiolation of existing leaves. New leaves appeared shortly after weed removal and few plants died unless weed cover persisted for most of the growing season. Further weed germination was allowed on some plots. Although not removed until late autumn, these weeds only had adverse effects on crop growth where initial weeding had occurred before mid-June. In one experiment, delaying weed removal until 6 July, 31 August or 2 November in the first year reduced fruit yield in the second (weed-free) year by 34%, 54% and 67% respectively. In a later experiment, competition from weeds until July or later in the first growing season gave fruit yields similar to those in the first experiment, but totally weed-free plots and those kept clean after weeding in mid-June produced less fruit than plots which remained weedy between mid-June and mid-August. It is suggested that competition from uncontrolled stolon growth in this experiment severely inhibited crown and hence truss production on plots which did not suffer weed competition. Unless left untouched until early September, weeds had less adverse effect on truss production than the stolons which they displaced. The results are interpreted in relation to improving the efficiency of weed control techniques.     

出芽短梗霉菌菌株PA-2的除草活性及对作物的安全性

从青海省平安县发病杨树叶片上分离得到菌株 PA-2,其发酵滤液对多种阔叶杂草表现出较好的除草活性。对该菌株的培养特征和16S rDNA基因序列分析后,确定其为短梗霉属出芽短梗霉菌Aureobasidium pullulans。盆栽试验表明,其发酵滤液对供试阔叶杂草猪殃殃、藜、冬葵、酸模叶蓼及禾本科野燕麦的鲜重防效分别达到87.25%、78.46%、82.25%、62.11%、80.27%。作物安全性试验结果表明,其发酵滤液对小麦、蚕豆、青稞很安全,对油菜、豌豆有轻微影响。综上所述,菌株 PA-2具有作为微生物除草剂的开发潜力。     

Radar Studies of Insects

Abstract

Yield and weed growth in dry-seeded rice (Oryza sativa L.) were unaffected by method of seeding. Weeds depressed rice yields by 95%. Fourteen weed species were found growing in association with dry-seeded rice at maximum flowering of the weeds. Echinochloa colona (L.) Link and Leptochloa chinensis (L.) Nees were the major weeds. A dramatic change in the weed flora was observed in transplanted rice planted immediately after the harvest of the dry-seeded crop. Only five species grew in association with the transplanted crop. Monochoria vaginalis (Burm.) Presl. dominated. E. colona and L. chinensis were present in transplanted rice but were only minor weeds. The number of weeds in the transplanted crop was less than 50%, and weighed only 5% as much as those in the dry-seeded crop. There was no carryover of the weed control treatments from the dry-seeded crop to the transplanted crop.     

广东省稻田杂草控制效果及影响因素

为了解常规管理条件下对广东稻田杂草的控制效果及其影响因素,于2015年对粤东、粤西、粤北地区及珠江三角洲的早、晚季稻田杂草进行了调查分析。结果表明:在常规控制措施下稻田中综合草害指数与水稻产量呈负相关,推荐剂量的除草剂不能有效控制稻田杂草的危害,特别是在早季需要辅以人工措施对稻田杂草进行管理。稻田杂草对除草剂产生了不同程度的抗药性。化学除草剂成本低,水稻种植者目前仍可以通过更换除草剂品种和加大剂量对杂草进行控制。化感抑草品种的推广需要在品质和产量上进一步满足生产的需要。在杂草耐药性增加、环境和政策要求减少化学除草剂投入的双重压力下,选育具有化感抑草效果的水稻品种,结合农艺措施,应该成为今后稻田控草的发展方向之一。     

辽宁省果园杂草发生情况调查

采用倒置W九点取样法调查辽宁省果园杂草,结果明确辽宁省果园杂草有24科72种,其中阔叶杂草占73.61%,禾本科占15.28%,其他杂草占11.11%;一年生杂草占80.56%,多年生杂草占19.44%。相对多度达10%以上的杂草依次为鹅观草、藜、鸭跖草、三叶鬼针草、小飞蓬、刺儿菜、铁苋菜。其中鹅观草和藜相对多度在15%以上。     

Weed flora of water rice in the Red River Delta,Vietnam

The occurrence of weeds in water rice was surveyed in the Red River Delta, Vietnam during spring and summer rice-growing seasons in 1995 and 1996. Sixty different weeds from 19 plant families were recorded. The most important plant families as weeds of rice were Poaceae and Cyperaceae. The most important weed however was Rotala indica (Willd.) Koehne (Lythraceae) followed by Echinochloa crus-galli (L.) Beauv. and Cyperus difformis L. A brief comparison of this rice weed flora and those of Australia and California was made.     

丁草胺、乙氧氟草醚对杂草的毒力及混配的协同增效作用

测定了丁草胺、乙氧氟草醚对稗草Echinochloa crusgalli （L.） Beauv及以刺苋Amaranthus spinosus L.、繁缕Stellaria media （L.） Cyr.为代表的阔叶杂草的毒力,并证实将两者混配成丁乙水乳剂对稗草及阔叶杂草具有明显的协同增效作用,其中,质量比为14∶1混剂的共毒系数（CTC）分别为164.0和288.5。田间试验亦证明混剂能提高药效,扩大杀草谱,延长持效期,具有较显著的除草作用。     

Herbicidal efficacy and selectivity of pyribenzoxim in turfgrasses

Three field trials were conducted from 2003–2004 at Utsunomiya University, Japan, to evaluate the safety and herbicidal activity of pyribenzoxim (benzophenone O -[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxybenzoyl]oxime) in turfgrass. Pyribenzoxim showed a high level of safety in bentgrass ( Agrostis palustris Huds.) and zoysiagrass ( Zoysia matrella ) ≤ 300 g ai ha⁻¹ and it controlled various major grass weeds, including annual bluegrass ( Poa annua L.), large crabgrass ( Digitaria sanguinalis L.), and green foxtail ( Setaria viridis L.), and broadleaf weeds, including common dandelion ( Taraxacum officinale Weber), horseweed ( Erigeron canadensis L.), shepherd's-purse ( Capsella bursa-pastoris (L.) Medic.), common chickweed ( Stellaria media L.), common lambsquarters ( Chenopodium album L.), creeping woodsorrel ( Oxalis corniculata L.), and common dayflower ( Commelina communis L.) by fall or spring application. In comparison with bispyribac-sodium (sodium 2,6-[bis(4,6-dimethoxy-2-pyrimidin-2-yl)oxy]benzoate), pyribenzoxim showed a higher safety level in bentgrass and a stronger herbicidal activity on grass weeds; in particular, annual bluegrass and large crabgrass.     

A COMPARISON OF THE GROWTH AND COMPETITION BEHAVIOUR OF SEEDLINGS AND PLANTS FROM RHIZOMES OF AGROPYRON REPENS (L.) BEAUV. AND AGROSTIS GIGANTEA ROTH

Summary. Seedlings and plants derived from single-node rhizome fragments of Agropyron repens and Agrostis gigantea were grown in au unheated glasshouse, separately or together with wheat ( cv. Kolibri), in sandy loam soil in well-spaced pots, adequately watered and moderately fertilized. Samples of crop and weeds were taken for growth analysis in mid- May, late June and early August (when the wheat was ripe).
On average, wheat decreased the weight of weed shoots by 84% and of rhizomes by 77%, but the weeds decreased the weight of wheat shoots by only 7% and of grain by 13%. Without wheat, seedlings of both weed species had, by late June, grown as much as plants from rhizomes, but with wheat, the weed seedlings were throughout most of the experiment more susceptible to competition than were plants from rhizomes. There was no simple relationship between the final dry weights of the weeds and the amount they decreased wheat yield: although Agropyron seedlings in competition with wheat were much lighter than Agrostis from rhizomes, they decreased grain yield of wheat as much, suggesting that they competed more intensely for a limiting factor, possibly nitrogen.
It is concluded that the faster initial growth rate of wheat seedlings relative to the weeds from rhizomes and a larger initial seed reserve relative to the weed seedlings enabled the wheat to dominate the weeds.
Comparaison de la croissance et comportement compétitif de plantules et de plantes issues de rhizomes d'Agropyron repens ( L.) Beauv. et d' Agrostis gigantea Roth