几种除草剂在燕麦田的应用效果

通过9种除草剂1,0个处理,对3个燕麦品种进行3次重复试验,初步筛选出异丙甲草胺＋苯达松茎叶喷雾对燕麦等禾本科杂草具有理想的防除效果。     

野燕麦生防真菌燕麦叶枯菌的分离培养及致病性研究

１９９３年５月在江苏南京发现自然罹病的野燕麦植株，对其病原真菌进行鉴定、分离，并对其培养特性作了初步研究，结果表明，其病原菌为燕麦叶枯菌，该菌在ＰＤＡ培养基上产生灰白色中央隆起的粗糙形菌落，不产孢；在营养缺限型的燕麦粒培养基或水琼脂上的小麦秸秆表面可产生有性阶段子囊果和少量分生孢子。菌丝体接种整株幼苗或离体叶片试验表明，该菌只侵染野燕麦而不感染小麦，是一种潜在的防除野燕麦的真菌除草剂菌株     

不同剂量除草剂对皮、裸燕麦光合特性及产量形成的影响

试验采用单因素随机区组设计,研究两种茎叶除草剂(立清和麦喜)在三个浓度下对皮燕麦‘陇燕3号’和裸燕麦‘白燕2号’生产性能指标及不同生育期倒二叶气体交换参数的影响,并通过综合评价,筛选高效除草剂的种类和剂量,以探讨除草剂对燕麦光合生理特性的作用机理。结果表明,在除草剂适宜浓度范围内(立清675~2 025 mL·hm~(-2)、麦喜90~270 mL·hm~(-2)),与未施用除草剂相比,除草剂中、高浓度对燕麦子粒产量有明显促进作用,最高增幅达34.67%。两种茎叶除草剂对燕麦光合特性的影响为短期刺激效应,在皮、裸燕麦生长前期(分蘖期、拔节期)除草剂对叶片的叶绿素相对含量(SPAD)、净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)均有所抑制,对胞间CO2浓度(Ci)和水分利用效率(WUE)有所促进,且随着除草剂浓度的提高,各光合指标的变幅增大,在两种除草剂高浓度处理下,皮燕麦和裸燕麦生长前期的Pn值平均比对照低42.86%和50.65%,WUE高于对照99.47%和86.44%,开花期后这种影响则逐渐趋于缓和。通过对光合及产量指标的主成分分析,将13个单项指标转换为3个相互独立的综合指标,最终确定燕麦倒二叶Tr、SPAD、Pn及子粒千粒重可作为除草剂安全高效评价的参考指标,筛选出除草剂麦喜浓度在180 m L·hm~(-2)时效果最佳。     

不同配比除草剂燕麦除草研究初探

为了解决燕麦生产中日益突出的草害问题,通过对燕麦进行不同配比的除草剂应用试验,测得用药后各处理杂草鲜重和小区产量,并以此数据测算各处理杂草防效和产量挽回损失率,经方差分析评价各配比除草剂,选出多个较好的配方。其中二甲戊乐灵播后苗前处理和嗯草酮播后苗前处理对单子叶杂草、双子叶杂草的防效及小区产量挽回损失率均与人工除草对照无差异,同时又显著好于无药剂对照。     

兰州农药厂燕麦畏工业生产技术通过鉴定

野燕麦是我国西北、东北、西南、中原16省(区)的农田恶性杂草,受害而积约6000万亩,减产一般20～40％,严重的达60％以上,甚至毁种绝收。我省是受害严重的省(区)之一,危害面积达1300万亩以上,严重的500万亩,每年损失粮食达4—5亿斤。 为了防除农田野燕麦,甘肃省农科院植保所从1967年以来,先后从数十种除草剂的试验比较中,确定燕麦畏是防除农田野燕麦的优良内吸选择性除草剂,并提出了一套切实可行的应用技术。但是,由于当时燕麦畏国内尚不能批量生产,限制了它的推广应用。兰州农药厂根据农业生产需要,1983年开始试制燕麦     

南京市区野燕麦防除试验

1982～1984年,先后应用阿畏达(即燕麦畏,又名野麦畏)、禾草灵、燕麦敌1号和2号、绿麦隆等10种除草剂进行了野燕麦的防除试验,结果以阿畏达、禾草灵和燕麦敌一号防除效果较好。对40%阿畏达和36%禾草灵进行了不同剂量的试验,前者用量每亩0.1斤、0.15斤、0.2斤和0.25斤,防效分别为88.3%、94.9%、95.8%和99.1%,后者用量每亩0.1斤、0.2斤、0.3斤和0.4斤,防效分别为95.6%、99.6%、100%和100%。     

青海省春油菜田杂草发生危害与防除技术研究

调查研究了青海省春油菜田主要杂草种类、危害损失及春油菜田野燕麦、Bian蓄、苣荬菜等杂草的发生特点和杂草群落演替趋势;试验筛选了近20种对春油菜田野燕麦和一年生阔叶杂草有较好防除效果的化学除草剂及混配剂。     

燕麦畏与燕麦敌苗水期防除野燕麦技术的研究

野燕麦(Avana fatua L.)是我省农田恶性杂草,分布广适应性强、密度大、出苗不整齐。幼苗期与小麦不易区别,加之繁殖率高、种子随成熟随脱落,极难防除。野燕麦的大量滋生,严重影响了作物的生长发育,导致减产歉收。1967年以来,我们先后在河西走廊的玉门、武威、嘉峪关、永昌等地,应用燕麦畏(triallate)与燕麦敌(diallate)等除草剂,进行防除野燕麦的试验研究,最初几年在播后苗前讲行土壤处     

“八五”期间我省农田杂草科学研究和除草剂开发应用的商榷

一、“七五”期间取得的主要进展“七五”期间我省在杂草生物学、生态学研究和除草剂开发应用方面取得了较大的进展。先后完成了移栽稻田多年生杂草——扁秆蔍草的国家攻关课题研究,成功地引进了扫茀特、新马歇特、农得时、杀草丹等新型除草剂并筛选出一些高效、经济、安全的稻田一次性除草剂配方,完成直播稻田、棉田、果、桑、茶园杂草发生消长规律和化学防除系列配套技术的研究;在麦田方面,引进新的除草剂如骠马、燕麦畏、野燕枯、百草敌、使它隆、巨星等防除单双子叶杂草的除草剂。改进了绿麦隆的使用技术,采用施药和盖草结合,轮作换茬,少免耕交替等综合防除技术控制杂草,取得了较大的成绩;油菜田在解决禾本科杂草防除技术     

几种除草剂防除野燕麦的效果及其影响因素

近年来,苏北盐垦区麦田野燕麦扩展蔓延十分迅速,已严重威胁小麦生产。1983～1984年我场普查了13个分场、49个大队、177块条田的9735亩麦田,有野燕麦的麦田占53.7％,严重田块有野燕麦71.9株/米~2,最严重的田块有154株/米~2,小麦减产2～5成。近年来我场进行了进口与国产除草剂防除野燕麦试验、示范,现将试验示范结果总结如下: 一、野麦畀Avadex防治野燕麦的效果     

Real-time weed detection, decision making and patch spraying in maize, sugarbeet, winter wheat and winter barley

Information on temporal and spatial variation in weed seedling populations within agricultural fields is very important for weed population assessment and management. Most of all, it allows a potential reduction in herbicide use, when post‐emergence herbicides are only applied to field sections with weed infestation levels higher than the economic weed threshold; a review of such work is provided. This paper presents a system for site‐specific weed control in sugarbeet (Beta vulgaris L.), maize (Zea mays L.), winter wheat (Triticum aestivum L.) and winter barley (Hordeum vulgare L.), including online weed detection using digital image analysis, computer‐based decision making and global positioning systems (GPS)‐controlled patch spraying. In a 4‐year study, herbicide use with this map‐based approach was reduced in winter cereals by 60% for herbicides against broad‐leaved weeds and 90% for grass weed herbicides. In sugarbeet and maize, average savings for grass weed herbicides were 78% in maize and 36% in sugarbeet. For herbicides against broad‐leaved weeds, 11% were saved in maize and 41% in sugarbeet.     

EFFECTS OF CHEMICAL WEED CONTROL ON THE GROWTH PATTERNS OF CONIFER TRANSPLANTS

Summary. Studies were undertaken to determine the tolerance of three conifer species to repeated applications of several herbicides over a 2-year period and the degree of weed control required to obtain optimal growth.
The results indicated that: (1) 60% or more weed control was required to obtain optimal growth of Picea glauca (Moench) Voss and P. pungens Engelm., while Pinus sylvestris L. showed optimal growth with average weed control as low as 40%; (2) weed competition did not affect the percentage survival of any of the three species under irrigated nursery conditions; (3) absence of visual injury symptoms was not an indication of the tolerance of a species to a herbicide; (4) severe weed competition caused an overall reduction in growth with significant reductions in stem diameter and in height and fresh weight of shoots; (5) herbicidal toxicity caused reductions in height, fresh weight or stem diameter but not necessarily of all three; (6) initial survival was affected only by those herbicides that were highly toxic at the doses applied; and (7) significant differences in growth, due either to weed competition or to herbicidal toxicity were apparent, in most instances, after the 2nd year's growth.
The treatments that gave 70% or more control each year with no apparent growth retardation over the 2-year period of the three species tested were: single yearly applications of neburon 4 lb/ac or linuron 2 lb/ac, two applications each year of DCPA (dimethyl 2,3,5,6-tetrachloroterephthalate) 10 lb/ac and directed application of sodium pentachlorophenate 15 lb/ac.     

Critical periods of weed competition in cotton in Greece

Four experiments were conducted in central Greece during 1997 and 1998 to determine the late-season presence of weeds in cotton (Gossypium hirsutum L.) and the critical times for removing weeds. Experiments were conducted in natural, heavily infested cropland. The presence of weeds for more than 3 weeks after crop emergence caused significant reductions in crop growth and lint yields. However, weeds that emerged 11 weeks or more after crop emergence did not adversely impact yields. Total weed biomass increased with increasing time prior to weed removal. A weed-free period of 11 weeks after crop emergence was needed to prevent significant reductions in cotton height, biomass, number of squares, and yield. These results indicated that postemergence herbicides or other control measures should be initiated within 2 weeks after crop emergence to avoid significant yield reduction. For greater efficiency, soil-applied herbicides in cotton should provide effective weed control for at least 11 weeks. Curvilinear regression equations were derived to describe the relationship between critical periods of weed presence and cotton growth and fruit development.     

Interaction between glyphosate and various herbicides for broadleaved weed control

The effects of several herbicides for broadleaved weed control on glyphosate (n-phosphonomethyl glycine) phytotoxicity to wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and wild oats (Avena fatua L.) were studied in the greenhouse. In tank mixtures, dicamba (3,6-dichloro-o-anisic acid), 2,4-D (2,4-dichlorophenoxy-acetic acid) and bromoxynil (3,5-dibromo-4-hydroxy benzonitrile) reduced the phytotoxicity of threshold rates of glyphosate on all three species. With increasing rates of the herbicides for broadleaved weed control relative to a fixed rate of glyphosate, there was a general trend towards increased antagonism. Increasing glyphosate rates above the threshold level in mixtures containing a fixed rate of herbicides for broadleaved weed control overcame the antagonism. Both the inert and active ingredients of 2,4-D amine and ester appeared to be involved in the antagonism. There was no reduction in glyphosate phytotoxicity on the annual grasses when 2,4-D or bromoxynil were sprayed sequentially at various times in relation to glyphosate. When droplets of bromoxynil and glyphosate were placed side by side on a leaf, glyphosate phytotoxicity was not reduced, whereas when the two herbicides were mixed and applied as one droplet, considerable reduction in glyphosate phytotoxicity occurred. These results suggest that the reduction in glyphosate phytotoxicity caused by tank mixing with herbicides such as 2,4-D, bromoxynil and dicamba may be due to a physical or chemical incompatability within the tank mixture rather than to a biological interaction in the plant.     

Weed flora distribution in Greek cotton fields and its possible influence by herbicides

A weed survey methodology was used for 2 years in three provinces in Greece to determine the abundance and spatial distribution of weeds in cotton (Gossypium hirsutum L.) fields. Based on a stratified random sampling procedure, the most frequently occurring weeds were counted in 150 cotton fields. The field surveys were conducted late in the growing season; hence, the weed populations consisted of species that had been present during the critical competitive period for the crop and may have contributed to yield losses.Solanum nigrum was the most abundant weed in the surveyed fields of the southern province, followed byCyperus rotundus, Convolvulus arvensis, Xanthium strumarium, Chrozophora tinctoria andCynodon dactylon, in descending order. The ranked weed flora in the fields of the northern province was differentiated, suggesting the geographical distribution of weed species. The weedsDatura stramonium andS. nigrum were recorded in high abundance and followed byAmaranthus spp.,Abutilon theophrasti, Portulaca oleracea, Chenopodium album andXanthium spinosum, in descending order. Although the use of preplant incorporated herbicides is the dominant practice in cotton cultivation, certain weeds continue to spread in increasing densities. http://www.phytoparasitica.org posting July 26, 2005.     

THE DEVELOPMENT OF HERBICIDES FOR POTATOES

Summary. Since 1961 the Weed Research Organization has been testing and developing herbicides for weed control in potatoes. Inthe three experiments which are reported, herbicides were compared with other forms of weed control. The first experimentin 1961 was exploratory and compared yields following hand-weeding versus no weed control versus several promising herbicides. The highest yield was produced by the hand-weeded crop. Several herbicide treatments applied before crop emergence gave useful selective weed control.
Assuming weed control to be necessary, selected herbicides were then compared in 1962 and 1963 with conventional mechanical cultivations. In both years successful weed control by herbicide resulted in a higher yield of potatoes than did mechanical cultivation although the soil-acting chemical used in 1962 caused some crop damage. The 1963 experiment included triangular planting patterns, at normal and high plant densities. Increases both in gross and marketable yield were obtained at normal plant density with the triangular arrangement as compared with the row crop. The high plant population resulted in the largest gross yield but a lower yield per plant and smaller average tuber size.     

Dinitroaniline Herbicide Cross-Resistance in Resistant Setaria italica Lines Selected from Interspecific Cross with S. viridis

Breeding of herbicide-resistant foxtail millet (Setaria italica (L.) Beauv.) is desirable in modern agriculture because no selective herbicide is available for this crop. Trifluralin-resistant millet lines obtained from a interspecific cross between a resistant green foxtail (Setaria viridis (L.) Beauv.) and a foxtail millet cultivar were tested for response to five dinitroaniline herbicides in greenhouse and field experiments. The results in the greenhouse study showed that the resistant type was cross-resistant to all tested herbicides. ED₅₀ values indicated that the highest resistance was obtained with trifluralin, the resistant biotype being seven and 33 times more resistant than the parent cultivar at the emergence and seedling stages, respectively. However, the doses recommended for efficient weed control resulted in some detrimental effects on emergence and growth in the field. Strategies for use of this resistance to control weeds in millet fields are proposed. © 1997 SCI.     

CONTROL OF REGENERATION IN ROOTS OF THE DEEP-ROOTED WEED CHONDRILLA JUNCEA L.

Summary. A system was developed for testing the ability of herbicides applied to the shoots of the deep-rooted weed Chondrilla juncea to inhibit the regeneration of buds on serial sections along the root. Auxin herbicides known to inhibit regeneration when applied directly to root sections and with a potential for translocation or slow metabolic conversion to an active auxin were selected for testing. The most effective herbicides tested were picloram, N -(diethylaminomethyl)-2,4-dichlorophenoxyacetamide and 2,4-dichlorophenoxy-acet- O -methylhydroxamic acid. Each compound reduced bud formation along 40 cm of root. The inhibition of regeneration by the sodium salt of 2,4-D was decreased at temperatures above 25°C. The growth retardants chlormequat chloride, chlorphonium chloride and B-995 were tested as inhibitors of regenerated-bud growth and emergence when applied to shoots; only B-955 was inhibitory. Amitrole and tris-(laziridinyl) phosphine oxide inhibited bud formation and growth.
Suppression de la régénération par les racines de Chondrilla juncea L., mauvaise herbe à encrainement profond.     

稻田眼子菜的生物学特性与化学防除

眼子菜(Potamogeton tepperi A.Benn.)是我省稻田中普遍发生的多年生恶性杂草,为害严重,人工很难除尽。本文是1972—1973年的研究结果。对眼子菜的形态特徵,特别是根茎与茎芽,作了详细的观察和描述。通过研究其分布与为害、发生周期、繁殖与蔓延、各生育期的特点等生物学特性,明确了支茎初发绿叶时,开始进入光合营养期,此时植株幼嫩,抗药力弱,为化学防除的有利时期。试验确定了扑草净、利谷隆、敌草隆、西草净等除草剂在我省各类稻作区安全、高效的用量范围以及混用方法。以昆明地区为例,模拟分析药性、草情、苗情、环境特点的相互关系,提出栽秧后20—40天为我省施药适期范围,以眼子菜由红叶期转入绿叶期时为指标,并经实践验证,这是可靠的。因地制宜地掌握用药量和施药适期,管好田水,可获得安全、高效、经济与省工、增产的效益。在全省已大面积推广应用,深受群众欢迎。     

Efficacy of chemical weed control in spring cereals in Finland

A national survey was conducted in Finland from 1982 to 1984 to determine the main weed species in spring cereals and the efficacy of herbicides on Finnish farms. The most common dicotyledonous weeds producing the highest biomass in spring cereals were Chenopodium album L., Galeopsis spp. L., Stellaria media (L.) Vill. and Lapsana communis L. The main grass weed was Elymus repens (L.) Gould. The average reduction of weed biomass by herbicide treatment was 75%. More reliable efficacy was obtained with herbicide mixtures than with MCPA alone.