Effects of soil solarization on soil-borne populations ofPythium aphanidermatum andFusarium solani and on the potato crop in Tunisia

Summary Soil solarization by mulching with polyethylene for 60 days during summer in Tunisia, was effective in reducing dramatically to a depth of 30 cm inoculum levels ofFusarium solani (Fs) from 3,000 to 450 propagules gram⁻¹ of dry soil. Population densities ofPythium aphanidermatum (Pa) were reduced from 1,700 and 3,000 to 0.5 and 1 propagule gram⁻¹ of dry soil in the top 15 cm and at 1–30 cm depth, respectively. After a subsequent autumn potato crop, populations ofPa remained very low in the previously solarized soil whereas propagule density in non-solarized soils was similar to the initial density. Also, inoculum level ofFs increased by 40% in nonsolarized soils while it remained unchanged in solarized soils, suggesting microbial processes that prevented soil reinfestation. All the annual weeds were eradicated by solar heating but not the perennial weedConvolvulus arvensis. Potato plant growth and yields were improved in solarized plots.     

南方亚麻田杂草防治药效试验及应用技术

南方冬春季种植的亚麻，田间主要杂草有看麦娘、牛繁缕、man草及碎米荠。试验表明：72%郁尔乳油每666.7m^2用量130ml，在亚麻播后发芽前封土处理，其鲜重防效达84.7%；17.5%快刀乳油、10.8%高效盖草能乳油及5%禾草杀星乳油每666.7m^2用量60ml，在亚麻出苗后20～30天喷雾，其鲜重防效分别为98.1%、87.1%和92.7%。上述药剂对亚麻安全无药害，一次用药能完全控制亚麻全生育期的杂草危害。     

内蒙古牙克石市油菜高产栽培技术

油菜是牙克石市主要栽培的作物,提高油菜的产量和品质对促进当地农业的发展和提高人们的生活水平有着重要的作用。经过多年的生产实践和实地调查,并参考国内相关的文献资料,加以整理分析,提出了油菜高产栽培技术。应尽量选择夏翻地播种油菜;如选择春秋翻地播种,首先要保证有足够底墒、杂草基数低、整地质量好的地块。选择青杂2号、青杂3号、青杂5号等优良的品种并进行清选和药剂处理;提出了适宜的播种期和最佳密度,合理的肥料配方;田间科学管理措施,病虫草害的综合防治技术等成套的综合高产栽培技术。此项技术经过在生产上应用,表现出油菜前期长势好、病虫害轻,产量和品质都有明显的提高,获得了较好的效果。     

小麦田除草剂应用技术

通过对麦田杂草生长状况以及影响麦田除草剂使用因素的剖析,针对性地提出了解决对策和途径,包括除草剂类型的选择,最佳防治期的选择,根据常见麦田的杂草选择何种化学除草药剂,除草药剂量的使用,提高除草剂喷施质量的要求等,并结合近几年我国小麦田的优势杂草种类,主要应用的除草剂分析了目前国内麦田杂草的抗药性现状及防治对策。     

Interactions of fungicide-herbicide combinations against plant pathogens and weeds

The fungicide cyproconazole and four herbicides, DNOC, dicamba, ioxynil and bromoxynil, were tested singly and in mixtures against Rhizoctonia cerealis (in vitro and on wheat) and against Pseudocercosporella herpotrichoides (in vitro, as well as against two weeds, Avena fatua and Sinapis alba. Cyproconazole showed very strong fungicidal acitivity against both fungi. DNOC was inhibitory to the fungi in vitro but had little effect on the disease; dicamba had low activity against the fungi in vitro but prevented the disease on wheat. Ioxynol and bromoxynil were moderately fungitoxic both in vitro and against the disease. Cyproconazole-herbicide mixtures were synergistic in their action against both fungi in vitro and against the disease. The level of synergism depended on the relative proportion of fungicide and herbicide components in the mixtures. Mixtures of herbicides with cyproconazole against weeds were at best additive in their activity.     

小麦田阔叶杂草的生态经济杀除阈期研究

在麦田阔叶杂草达180－200株／m^2的情况下，进行了阔叶杂草的生态经济杀除阈期的研究，结果表明：苗后杂草干扰的相对时间（x)与相对产量（y)呈二次logistic曲线关系，表达式为：y=109.778/(1 exp(0.0071x-2.3281)）。苗后杂草的相对出苗时间（x）与小麦的相对产量（y)之间也呈二次logistic曲线关系，其表达式为：y=103.36(1 exp(-0.02x^2 0.0057x-1.5322)。根据上述两个模型进一步求出麦田阔叶杂草的生态经济杀除阈期约在小麦苗后的89－179天。此期间保持无草，有利于极大限度地控制杂草对小麦的危害。     

15%麦极WP对日本看麦娘等麦田恶性禾本科杂草的防治效果

采用盆栽方法,研究了15%麦极WP对日本看麦娘、野燕麦、雀麦和节节麦4种麦田恶性禾本科杂草的防治效果.结果表明:麦极300～450g/hm2处理能有效控制2～6叶期的日本看麦娘和野燕麦,但对节节麦和雀麦防效不大.经济用量为300g/hm2,对野燕麦和日本看麦娘的防治效果可分别达到100%和93.2%以上.     

使它隆乳油对小麦田阔叶杂草的药效试验

以200g/L使它隆乳油防治猪殃殃、荠菜、大巢菜、播娘蒿等常见的小麦田间一年生阔叶杂草,结果表明,此浓度药剂对这些小麦田间杂草有较好的防治作用,对不同的杂草防治效果略有不同。药后45d,对猪殃殃、荠菜、大巢菜、播娘蒿等的株防效可达81．58％～96．43％,鲜重防效达90．00％～97．94％。对小麦安全性好,增产效果显著。     

湿润直播稻田杂草出苗动态与发生规律

 1996～1997年在浙江嘉兴调查了湿润直播稻田杂草出苗动态和发生规律,并比较了直播与移栽,早稻、单季晚稻与连作晚稻直播,翻耕与免耕直播间杂草发生差异。湿润直播稻田杂草以稗草、千金子、异型莎草、节节菜、陌上菜为主,其次有通泉草、丁香蓼、水芹。禾本科、莎草科和阔叶杂草种类数分别占25.0%、18.8%和56.2%,出苗数量分别占11.2%、11.6%和77.2%。单季晚稻直播田稗草、千金子发生重于其他直播田,直播田稗草和千金子数量明显高于移栽田。直播田杂草于播种后3～4 d陆续出苗,1～3周达到高峰。连作晚稻直播田播后6～8周出现明显的第二个出苗高峰。以阔叶杂草为绝对优势的翻耕直播田杂草发生重于免耕田。直播田杂草数量自然消长呈现与出苗动态相同的趋势。直播田杂草发生以稗草、千金子、丁香蓼较早,节节菜、陌上菜、通泉草次之,异型莎草和水芹较迟。稗草、千金子及其他几种主要杂草出苗高峰均呈单峰状态,而节节菜、陌上菜在连作晚稻直播田的出苗则为双峰。     

沿江圩区农作物病虫草害演替及综合治理对策

沿江圩区主要农作物病虫草害演替呈现以下特点 :种类增加 ,不断出现新的病虫为害 ;危害期拉长 ,发生程度加重 ;突发性病虫暴发成灾 ;螟虫危害趋于复杂化等。为此制定了近期与长远期综合治理措施 ,及时有效地控制其危害