灭幼脲Ⅰ号及其类似物对粘虫生长发育的毒性研究

灭幼脲Ⅰ号及其类似物是一类取代苯酰苯基脲类杀虫剂,又称几丁质合成抑制剂。据报道用敌米灵(Dimilin)处理大白菜粉蝶幼虫后,其内表皮中放射性标记酪氨酸的结合受到抑制,从而阻碍了几丁质的合成。多种昆虫组织培养的生物化学研究,也发现     

温度和湿度对白僵菌孢子粉贮藏期和寄生力的影响

白僵菌作为微生物杀虫剂,在我国已广泛应用。本文仅报道了白僵菌孢子粉在不同温度和湿度条件下对其贮藏期和寄生力的影响。一、材料与方法 (一)以吉林玉米螟白僵菌9号、湖南叶蝉白僵菌751号和广东省新会松毛虫白僵菌为供试菌株,采用PDA 0.3％蛋白胨培养基,25℃培养20天,形成孢子后收取表面孢子层,经干燥研碎团块120目过筛取孢子粉,装入称量瓶内,铜纱包扎,分放盛有不同饱和盐类的干燥器中贮存。     

玉米青枯病病原菌的分离及其致病性测定技术的研究

 在1985~1995年期间,先后对国内16个省、市、区的1394份玉米青枯病株进行分离,腐霉的分离频率为63.8%,而镰刀菌则为36.4%。两菌在各省市区的分离频率不尽相同。深入研究的结果表明,培养基种类、分离部位、不同病级的病株或病株分离(采集)的季节对分离结果有直接影响。#br#根据Koch氏法则,从病株上分离的腐霉和镰刀菌必须回接在感病的玉米株上,测定其致病性。接种结果表明,腐霉具有致病性,应是玉米青枯病的病原菌,而镰刀菌则不是。研究结果还表明,接种方式、玉米生育期、接种的菌量、盆土含水量对致病性测定的成败具有重大影响。     

OBSERVATIONS ON THE RELATIONSHIP BETWEEN THE ADSORPTION OF DIURON AND THE NATURE OF THE ADSORBENT

Summary. A series of adsorption experiments was carried out in order to determine if there was significant competition for adsorption sites between diuron and water. Adsorption of diuron was much lower on hydrophilic materials such as cellulose, chitin, aluminium oxide and a soil mineral fraction than on the less hydrophilic ion exchange resins, lignin, carbon and a soil organic fraction. Methylation with methanolic HCL or diazomethane increased adsorption by the soil organic material, but methylation with dimethyl sulphate did not.
The soil mineral fraction adsorbed considerably more diuron from petroleum spirit solution than from aqueous solution, but the organic matter preparation adsorbed more from aqueous than from petroleum solution.
It was concluded that there is competition between water and diuron for adsorption sites and that diuron is a more effective competitor at soil organic matter surfaces than at soil mineral matter surfaces.
Observations sur la relation entre l'adsorption du diuron el la nature de l'adsorbant     

三唑酮、三唑醇对小麦纹枯病菌形态和生理的影响

 小麦纹枯病菌(Rhizoctonia cerealis)在加入三唑酮(Triadimefon)或三唑醇(Triadimenol)的培养液中生长时,菌丝形态和生理发生明显的改变。菌丝畸形,表现为细胞肿大,细胞分隔处菌丝缢缩;药剂处理后,等量菌丝的麦角甾醇含量下降,1、5μg/ml的三唑酮和三唑醇处理,麦角甾醇含量比对照减少45.155.9%和27.5、48.9%;菌丝在药剂处理后,电解质渗漏增加,5μg/ml药剂处理一小时后,三唑酮组的菌丝之细胞电解质渗漏达2.58%,三唑醇组的渗漏为2.19%,空白对照组仅为0.65%。本研究结果表明,三唑酮、三唑醇对小麦纹枯病菌具有直接的伤害作用。     

黄土高原人工草地的土壤水分动态及水土保持效益研究

通过９年观测，黄土高原人工草地土壤水分的季节性变化可划分为三个阶段，在此基础上模拟不同人工草地土壤水分的变化规律；随着牧草生育期的延长至第９年，人工草地土壤水分恢复程度逐渐减弱；沙打旺生存能力极强，能够高效地利用深层土壤贮水；用数学模型可以模拟不同人工草地的水土流失，将植被因子引入水土流失方程，可以定量描述对水土流失的影响；反映植被、土壤等因子与水土流失关系的复合因子Ａ￣１值，基本上代表不同人工草地水土流失状况。     

THE EFFECTS OF SUB-LETHAL DOSES OF MCPA ON THE MORPHOLOGY AND YIELD OF VEGETABLECROPS

Summary. The effects of sub-lethal doses of MCPA-sodium on the morphology and yield of red beet, turnip and onion and on the morphology of spinach were studied in field and glasshouse experiments. Epinastic responses of beet were seen at 0.003 lb/ac a.c., but no serious formative effects or yield reductions occurred below 0–07 lb/ac and plants were only killed by doses above 0–1 lb/ac. Spinach was affected at 0–06 lb/ac, the lowest dose used, but the plants were not killed at 0–33 lb/ac. Epinasty in turnip occurred at 0–002 lb/ac, and at 0–01 lb/ac many of the roots were abnormal, while spraying with 0–1 lb/ac and above resulted in severe distortion or death of the plants. Onion was the least affected of all the crops studied. When a welting agent was included in the spray epinasty occurred at 0–3 lb/ac, but there were no serious formative effects or yield reductions below 1–0 lb/ac. The symptoms of injury in onion were often transitory because the affected parts were replaced as the bulb developed.
Effets de doses sub-léthatles de MCPA sur la morphologie et If rendement des cultures légumiéres. V. Betteraves, Epinards, Navets et Oignons     

EFFECT OF TEMPERATURE ON THE ACTIVITY AND PERSISTENCE OF AMITROLE AND 2,4-D

Summary. One leaf of each of several tomato plants 5–6 weeks old maintained at 55, 70 or 85° F was dipped in 0.05 M amitrole or 0.005 M 2,4-D solution. The treated leaf was removed 1 week later. Scions taken from untreated plants were grafted to the treated plants at intervals up to 4 months after treatment.
Amitrole-treated plants maintained at 55° F were killed within 1 month but those at 70 and 85° F recovered.
Plants treated with 2,4-D showed typical symptoms when maintained at 70 and 85° F but no symptoms at 55° F. Scions grafted on plants maintained at 55, 70 and 85° F for 60 days after 2,4-D treatments exhibited typical symptoms. Grafts made more than 60 days following the 2,4-D application did not exhibit symptoms except a slight malformation on the plants held at 55° F.
New growth on the scions grafted up to 103 days after amitrole treatment on plants which had been maintained at 70 and 85° F exhibited typical amitrole symptoms (i.e. white foliage) but scions grafted after this lime did not. New shoots developing from buds on the treated plants also produced green growth 115 days after treatment but produced white foliage prior to that time.
Effet de la température sur l'activi'ité et la persistance de l'aminotriazole et du 2,4-D     

水稻白叶枯病发生流行预测的研究

 作者应用多重回归法和噬菌体技术对水稻白叶枯病的发生流行趋势的预测作了研究。结果表明:(1)根据始病前两旬降水量≥ 0.1毫米日数和越冬期(12月至2月)三个月的日平均气温,可以预测田间始病期,(2)在水稻生育期内测定稻田水中噬菌体量,并根据病害流行前两旬连续三次测定噬菌体累计量、降水量和降水量≥ 10毫米日数等可预测水稻后期病害的流行趋势。同时分析了影响病害流行的主导因素(降水量≥ 10毫米日数和噬菌体量)及建立了多重回归预测模式。     

温度和湿度对巴西豆象生长发育的影响

作者利用豇豆(Vigna unguiculata L.)种子作饲料,在20、24、28、32、36℃五种温度和相对湿度90%条件下对巴西豆象(Zabrotes subfasciatus Bohema)进行研究,结果表明巴西豆象未成熟期发育起点为15℃,生长发育繁殖最适温区为28—32℃。此外,还考察了湿度因子对巴西豆象生长发育和繁殖的影响。     

棉红蜘蛛为害对棉花生长发育和产量的影响及其防治指标的研究

作者从1978—1983年对棉红蜘蛛的为害进行研究。结果表明,棉花苗期受害后,棉株高度降低,果枝数和青铃数减少。蕾铃期受害后,青铃数明显减少。棉株受害后影响产量。为害指数(x)与减产率(y)的关系式为:苗期y=10.40x±1.21(0≤x≤2.36),蕾铃期y=12.53x±1.5(0≤x≤2.5)。在田间调查时,可根据红斑株率(n)与红斑株平均为害指数(m)的关系式m=0.2165+0.00889n±0.14推算出减产率。利用y=10.40x±1.21,y=12.53x±1.5和m=0.2165+0.00889n±0.14,结合当地棉花的生产水平,可确定以红斑株率表示的防治指标。红斑株率易于调查和推广应用。     

芦笋小管蚜种群的光温效应

温度是影响芦笋小管蚜种群的主要因素之一。１－４龄阪雌蚜的发育起点温度依次为３．２２１、５．６３１、４．８０４和１０．８５７℃。有效积温依次为７１．５５６、５２．７６０、５２．５３７和４５．５６２日度。供试温度中２４．５２℃对蚜虫最有利。在此温度下ｒｍ、ｂ、λ的值最大，而ｄ则最小。孤雌蚜４个龄期，在２４．５２℃，完成１个龄期２天左右，若虫期共８．９８天。孤雌蚜的繁殖能力极强，条件适宜时，１头雌蚜一生     

丙酸和丙烯酸类化合物对白背飞虱取食行为的影响

在害虫的防治中连续及加量的喷施剧毒杀虫剂,造成了环境污染,提高了农业生产成本,也导致害虫的再度猖獗。因此,人们都在寻找既能控制害虫种群的发展,又能减轻对环境的污染和降低成本的昆虫拒食剂。近年来,有关拒食剂的研究报道不断增多。李芳等(1988)报道丙酸与丙烯酸类化合物对刺吸式口器的桃蚜(Myzus persitae)具有一定的拒食作用。刘光杰等(1992)报道呋喃丹的亚致死剂量对我国水稻主要害虫白背飞虱(Sogatella furcifera Horvath)具有拒食作用。因此,作者选用4种丙酸类化合物研究对白背飞虱的拒食作用。     

THE EFFECTS OF SUB-LETHAL DOSES OF MCPA ON THE MORPHOLOGY AND YIELD OF VEGETABLE CROPS

Summary. The effect of sub-lethal doses of MCPA-sodium on the morphology, growth and yield of carrots and parsnips was studied in twenty replicated field experiments. Slight epinasty was produced in carrots by doses as low as 0.002 lb/ac a.e., but formative effects were not usually seen below 0.01 lb/ac. Crop weight was only reduced by doses greater than 0.1 lb/ac, but abnormalities rendered a proportion of the roots unmarketable at doses below 0.05 lb/ac. Small plants were sometimes killed by 0.3 lb/ac, but larger plants survived treatment with up to 0.5 lb/ac. Tests on carrots which were unmarketable on grounds of appearance failed to reveal any effect of MCPA on flavour, sweetness or texture of the roots. The effects of MCPA on parsnips were similar to those on carrots, but the expression of injury symptoms was generally less marked.
Les effets de doses sub-létales de MCPA sur la morphologie et le rendement des cultures légumières III. Carottes et panais     

预测预报准确度评估方法的研究

探讨了预测准确度的概念和评估的要素，在评述现行的几种计算公式的基础上，提出一种改进方法     

THE INFLUENCE OF SIZE OF SPRAY DROPLETS ON THE HERBICIDAL ACTIVITY OF DIQUAT AND PARAQUAT

Summary. Single droplets ranging in size from 250 to 1000 μ diameter and concentrations of diquat and paraquat over the range 0–09–0.75% ion were examined for herbicidal activity. Size of droplet and concentration of herbicide in the droplet were shown to have a marked influence on activity. An increase in droplet size above 250 μ increased herbicidal efficiency. An optimum was reached between 400 and 500 μ while activity fell off with a further increase to 1000 μ.     

THE EFFECTS OF SUB-LETHAL DOSES OF MCPA ON THE MORPHOLOGY AND YIELD OF VEGETABLE CROPS

Summary. The effect of sub-lethal doses of MCPA-sodium on the growth, yield and marketability of summer cabbage lettuce was studied in seventeen replicated field experiments.
Initial epinasty was produced by doses as low as 0.002 lb/ac a.e., and formative effects of the leaves developed at doses below 0.01 lb/ac. In plants treated at early or intermediate growth stages, two distinct types of formative effects occurred, With doses in the range 0.0025-0.03 lb/ac, a zone of characteristic abnormal leaves developed. This reduced the marketability of the crop and the maturity was delayed, but the weight per plant at harvest was not affected. At higher doses these a abnormal leaves were not evident but the whole plant became distorted, growth was suppressed and few marketable plants were produced. In plants treated at the hearting stage, plant weight and maturity were not affected, but the marketability was reduced at doses of 0.01 lb/ac and above. The effects produced by MCPA in cos and curly crisp lettuce were compared with those produced in cabbage lettuce.