三角坐标图法在农药水分散粒剂配方研制中的应用

介绍了一种快速筛选农药水分散粒剂最佳配方的实用方法,该方法以3种变量的含量为坐标建立三角坐标系,选用重要且快速简单的质量评价指标为试验指标,适用于农药配方研制中两种或3种助剂的配比研究,可以提高水分散粒剂配方筛选的科学性和效率。室内以质量分数为43％的戊唑醇水分散粒剂配方为例,运用三角坐标图法对分散剂、润湿剂进行了最佳配比和含量的筛选和验证,取得了理想的结果。     

丁草胺与苄嘧磺隆混剂最佳配比的研究

在室内对我国广大水稻产区广泛应用的丁草胺与苄嘧磺隆进行了最佳配比研究。结果表明，丁草胺与苄嘧磺隆混用，配比在16-23：1之间选用为宜。     

7种杀菌剂对绿豆根腐病菌的毒力测定及增效混剂配比筛选

以绿豆根腐病主要致病菌尖孢镰孢菌和立枯丝核菌为供试靶标病菌,测定了7种杀菌剂对供试病菌的室内抑菌毒力,在此基础上进行了混配增效药剂筛选实验。结果表明,多菌灵和氟菌唑对尖孢镰孢菌的EC50分别为43.336μg/mL和1.501μg/mL;福美双和氟菌唑对立枯丝核菌的EC50分别为66.38μg/mL和0.128 μg/mL。二元混配增效药剂筛选结果显示,福美双和氟菌唑按照6：4体积比混配对两种供试病菌的室内抑菌增效作用显著,为最佳增效配比。     

伊维菌素和丁氟螨酯复配最佳配比筛选及田间药效评价

本研究采用药膜法测定了伊维菌素、丁氟螨酯对朱砂叶螨的室内毒力。采用共毒因子法、共毒系数法对最佳配比进行筛选并加工成5%伊维菌素·丁氟螨酯水乳剂进行田间防效试验。结果显示:伊维菌素∶丁氟螨酯=1∶1时,共毒系数(CTC)高达265.66。伊维菌素·丁氟螨酯配比的数学模型为Y=-1.3787 X2+79.264 X-881.41,R2=0.9154,理论最佳配比为1∶1,CTC=257.77。田间防效显示:5%伊维菌素·丁氟螨酯水乳剂药效良好,有效成分用量为25~50mg/L时,药后3、10、20d防效均高于80%。     

贵州易旱坡地黔兴201玉米高产氮磷钾配比研究

为了解决贵州地区玉米高产施肥问题,以黔兴201玉米为研究对象,采用L9(34)氮磷钾三因素三水平试验方法,设计了不同的氮磷钾配比,通过在贵州平坝地区田间试验研究玉米的营养特性和施肥效应,以筛选出最佳氮磷钾配比.结果表明:氮肥360 kg/hm2、磷肥225 kg/hm2、钾肥105 kg/hm2印氮磷钾比例为1:0.6...     

溴嘧草醚与胺苯磺隆混配制剂对油菜田杂草的室内防除效果筛选研究

溴嘧草醚(代号:ZJ0777)为化学结构新颖的油菜田专用除草剂,为扩大其杀草谱,提高除草活性,我们以日本看麦娘(Alopecurus aequalis)和小藜(Chenopodiumalbum)等为试验靶标进行了与胺苯磺隆(Ethametsulfuron)混用的室内防除效果配方筛选研究,并采用共毒系数法和等效线法对二者混用的联合作用进行评价。结果表明,两者混用后表现相加或增效作用,最佳配比为溴嘧草醚∶胺苯磺隆质量比为1:0.2。     

石灰在山药贮藏防病中的应用研究

[目的]山药贮藏过程常受病原物侵染危害而造成一定损失,但目前对其病害防治主要依靠化学农药.为减少化学药剂对环境的污染,提高食品安全,探究了石灰对山药贮藏期间病害的防治效果.[方法]选取潍坊市主栽品种大和长芋山药为研究材料,室内接种青霉菌后,分析了石灰与黏土的9个不同配比对青霉菌的抑制活性,同时进行了冷库贮藏试验.[结果]室内接种测定和冷库试验结果均显示熟石灰和黏土按照2﹕5的配比处理山药的防效最好,对筛选出的石灰泥最佳配比进行冷库贮藏中试试验,发现贮藏3个月后山药没有生霉腐烂,但端部切口处需切掉厚度约2～3 cm后才会出现白色组织.[结论]石灰和黏土按照2﹕5的比例处理山药能有效减少贮藏期间的腐烂损失,对山药产业的绿色发展具重要意义.     

甲维盐·氯虫苯甲酰胺组合物对草地贪夜蛾室内毒力测定及田间防治效果

为筛选出甲维盐与氯虫苯甲酰胺复配防治草地贪夜蛾的最佳配比,采用浸虫法测定了甲维盐、氯虫苯甲酰胺及组合物对草地贪夜蛾的室内毒力,并基于最佳增效配比进行了田间防治效果评价试验。结果表明,甲维盐和氯虫苯甲酰胺复配组合在二者质量比介于2∶8～7∶3范围内表现增效作用,以3∶7时增效作用最大,共毒系数CTC为173。基于该比例加工获得10%甲维盐·氯虫苯甲酰胺水分散粒剂,并以此开展田间防治草地贪夜蛾效果评价,结果表明,施药浓度高于有效剂量37.5 g/hm~2时,药后3、14 d对草地贪夜蛾的防效分别达到88%和84%以上,表现出良好的速效性和持效性。甲维盐和氯虫苯甲酰胺以质量比3∶7混配是防治草地贪夜蛾的良好配方。     

草甘膦铵盐、氯氟吡氧乙酸异辛酯及其混剂对空心莲子草生理指标的影响

以室内盆栽筛选结果为基础,以草甘膦铵盐及氯氟吡氧乙酸异辛酯单剂为对照药剂,研究了增效配比草甘膦铵盐-氯氟吡氧乙酸异辛酯(4∶ 1,有效成分质量比)对空心莲子草Alternanthera philoxeroider净光合速率、胞间CO2浓度、气孔导度、叶绿素及丙二醛含量等生理指标的影响。结果表明,该配比混剂处理对空心莲子草净光合速率和气孔导度的实际抑制率与理论抑制率的百分比在80% ~100%之间,表现出相加作用;而对胞间CO2浓度、叶绿素含量及丙二醛含量的实际抑制率与理论抑制率的百分比均在110%以上,表现出较强的增效作用。该配比混剂具有进一步加工应用的价值。     

咪鲜胺、氟环唑及其混配对水稻纹枯病室内毒力及田间防效

为筛选出对水稻纹枯病高效的新配方药剂及剂量,以咪鲜胺和氟环唑混配进行室内抑菌活性、持效期和田间药效测定。采用孙云沛法进行室内联合毒力测定,结果表明,供试的5种混配组合对水稻纹枯病菌的联合毒力均表现为增效,综合联合毒力、成本和持效期等因素,选择30%咪鲜胺·氟环唑微乳剂(2∶1)为最佳田间应用配比。田间药效试验亦表明,30%咪鲜胺·氟环唑微乳剂(20%+10%)158~180g/hm2的用量对水稻纹枯病有较好的防治效果。     

Hydrolysis rate and In vitro anticholinesterase activity of fenitrothion and S-methyl fenitrothion

Anticholinesterase activity in vitro of pure fenitrothion, S-methyl fenitrothion (SMF) and mixtures of both was studied using different sources of cholinesterase. SMF was two to three orders as active an inhibitor as fenitrothion. In the mixtures, 1 and 5% SMF significantly influenced the I₅₀ value of fenitrothion. The hydrolysis rates of both compounds are given. A method for the synthesis of pure SMF is also described.     

柿树炭疽病菌的生物学特性及几种杀菌剂对其的抑制作用

通过十字交叉法和血球计数板法测定了柿树炭疽病菌Collelotrichum gloeosporioides的生物学特性;采用菌丝生长速率法测定了7种常用杀菌剂对该病菌的抑制作用;选择5种市售杀菌剂进行了田间药效试验。结果表明:该病菌菌丝生长的最适温度为20~30 ℃,最适产孢温度为25~30 ℃,最适生长的pH值为5~6;在7种常用杀菌剂中,多菌灵、苯醚甲环唑、戊唑醇和氟硅唑对柿树炭疽病菌具有明显的抑制作用,EC50值分别为0.118 8、0.138 0、0.159 9和1.297 2 μg/mL。田间试验结果显示,25%咪鲜胺乳油600倍液、10%苯醚甲环唑水分散粒剂1 000倍液和25%戊唑醇水乳剂1 500倍液的防治效果分别为89.60%、88.56%、87.82%。     

Increasing complexity of resistance in host populations through intermating to manage rust of pearl millet

ABSTRACT Pearl millet inbreds Tift 23DB, Tift 85DB, PS748BC, and Tift 89D(2) were used to develop three categories of host mixtures (physical mixtures, random-mated populations, and mixtures of two-way and three-way crosses) representing different levels of complexity of resistance through increased heterogeneity within populations and through stacking of resistance genes within the heterogeneous populations. The potential of these mixtures to reduce rust epidemics was evaluated in the field. Area under the disease progress curves (AUDPCs) of all physical mixtures were less than the mean of the components in 1995 and were less than the mean of the components for five of the six mixtures in 1997. In 1996, AUDPCs of the physical mixtures were consistently greater than the mean of their components. AUDPCs of the random-mated mixtures and the mixtures of crosses were consistently less than the mean of the components in 1996 and 1997, with reductions ranging from 12 to 71%. Dry matter yield (DMY) of physical mixtures relative to the mean DMY of the components was inconsistent, ranging from 18% less to 50% more than the mean of the components. The random-mated populations and the mixtures of crosses yielded 18 to 40% more DMY than the mean yield of the pure stands of their components.     

Activities of mixtures of soil-applied herbicides with different molecular targets

The joint action of soil-applied herbicide mixtures with similar or different modes of action has been assessed by using the additive dose model (ADM). The herbicides chlorsulfuron, metsulfuron-methyl, pendimethalin and pretilachlor, applied either singly or in binary mixtures, were used on rice (Oryza sativa L.). The growth (shoot) response curves were described by a logistic dose-response model. The ED50 values and their corresponding standard errors obtained from the response curves were used to test statistically if the shape of the isoboles differed from the reference model (ADM). Results showed that mixtures of herbicides with similar molecular targets, i.e. chlorsulfuron and metsulfuron (acetolactate synthase (ALS) inhibitors), and with different molecular targets, i.e. pendimethalin (microtubule assembly inhibitor) and pretilachlor (very long chain fatty acids (VLCFAs) inhibitor), followed the ADM. Mixing herbicides with different molecular targets gave different results depending on whether pretilachlor or pendimethalin was involved. In general, mixtures of pretilachlor and sulfonylureas showed synergistic interactions, whereas mixtures of pendimethalin and sulfonylureas exhibited either antagonistic or additive activities. Hence, there is a large potential for both increasing the specificity of herbicides by using mixtures and lowering the total dose for weed control, while at the same time delaying the development of herbicide resistance by using mixtures with different molecular targets.     

Selection of pathotypes of Erysiphe graminis f.sp. hordei in pure and mixed stands of spring barley

Pathotypes of Erysiphe graminis f.sp. hordei were monitored at fortnightly intervals in pure and mixed stands of spring barley during the course of mildew epidemics in two field trials. Mixtures were composed of cultivars with Arabische (gene Mla12 ), Laevigatum ( Ml(La) ), and Monte Cristo ( Mla9 ) resistance, respectively. The three-way mixtures were either random or, in 1989, laid out as one-row mixtures (i.e., regularly alternating rows of different genotypes) or three-row mixtures (i.e., regularly alternating three-row strips of different genotypes), respectively. In 1990 only random mixtures and six-row mixtures were compared with pure stands. The virulence complexity (i.e., the average number of virulence factors per isolate with reference to Mla12, Ml(La) , and Mla9 ) was always maximal in the random mixtures. In 1989, linear regression of complexity on mildew generations gave significant b -values (slopes) of 0·049, 0·031, and 0·025 in the random mixture, one-row mixture, and three-row mixture, respectively; the b -value from pure stands was not significant. In 1990, another sampling technique allowed selection to be observed on each genotype in the mixtures separately. In the random mixture b -values were 0·048, 0·064 and 0·017 (not significant) on Mla12, Ml(La) , and Mla9 cultivars respectively. In six-row mixtures and in pure stands, there was no significant increase in complexity ( b > 0) on any of the mixture components. Although the frequency and relative fitness of complex pathotypes were higher in all types of mixtures than in pure stands, selection towards complex races was much less intense in row mixtures than in random mixtures in both field trials.     

Simple and sensitive method for determination of tetramethylthiuram disulphide (thiram)

A rapid, simple, direct and sensitive method has been developed for the determination of thiram (tetramethylthiuram disulphide) based on the formation of copper dimethyldithiocarbamate complex, which is rendered water-soluble by a cationic surfactant, cetytrimethylammonium bromide (CTAB). The method has been applied to the determination of thiram in synthetic mixtures, grain (wheat) samples and vegetables. © 1998 SCI     

10%溴虫腈水乳剂配方研究

采用相转移法,通过对溶剂及表面活性剂的筛选和配伍,确定了10%溴虫腈水乳剂的最优配方:溴虫腈质量分数为10％;溶剂甲苯质量分数为22.8％;表面活性剂EL-40、Span-80和农乳500#以质量比16∶ 3∶ 1复配,总质量分数为10%;蒸馏水质量分数为56.7%。用上述配方所制备的10％溴虫腈水乳剂各项指标合格,并且经常温、热贮(54℃±2℃)80 d未出现析油、分层现象,所制备的制剂黏度小、倾倒性佳,利于分装。     

Efficacy of insecticide mixtures against larvae of Culex quinquefasciatus (Say) (Diptera: Culicidae) resistant to pyrethroids and carbamates

The efficacy of insecticide mixtures of permethrin (pyrethroid) and propoxur (carbamate) was tested by larval bioassays on two strains of Culex quinquefasciatus (Say), one resistant to pyrethroids and the other resistant to carbamates. The method consisted in combining one insecticide at the highest concentration causing no mortality (LC0) with increasing concentrations of the second one. The concentration-mortality regression lines were determined for permethrin and propoxur alone and in combination, and synergism ratios (SR) were calculated in order to determine the magnitude of an increase or decrease in efficacy with use of the mixtures. With the pyrethroid-resistant strain (BK-PER), the results showed that propoxur at LC0 significantly enhanced the insecticidal activity of permethrin (SR50 = 1.54), especially on the upper range of the concentration-mortality regression. Conversely, when permethrin at LC0 was tested with propoxur against the carbamate resistant strain (R-LAB), an antagonistic effect was observed (SR50 = 0.67). With the BK-PER strain, an increased oxidative detoxification (MFO) appeared to be the main mechanism responsible for the synergistic interaction. Nevertheless, antagonism in the R-LAB strain is probably due to a physiological perturbation implying different target sites for pyrethroid (ie sodium channel) and carbamate insecticides [ie acetylcholinesterase (EC 3.3.3.7) and choline acetyltransferase (EC 2.3.1.6)].     

Effects of Wheat Cultivar Mixtures on Epidemic Progression of Septoria Tritici Blotch and Pathogenicity of Mycosphaerella graminicola

ABSTRACT The effects of host genotype mixtures on disease progression and pathogen evolution are not well understood in pathosystems that vary quantitatively for resistance and pathogenicity. We used four mixtures of moderately resistant and susceptible winter wheat cultivars naturally inoculated with Mycosphaerella graminicola to investigate impacts on disease progression in the field, and effects on pathogenicity as assayed by testing isolate populations sampled from the field on greenhousegrown seedlings. Over 3 years, there was a correspondence between the mixtures' disease response and the pathogenicity of isolates sampled from them. In 1998, with a severe epidemic, mixtures were 9.4% less diseased than were their component pure stands (P = 0.0045), and pathogen populations from mixtures caused 27% less disease (P = 0.085) in greenhouse assays than did populations from component pure stands. In 1999, the epidemic was mild, mixtures did not reduce disease severity (P = 0.39), and pathogen populations from mixtures and pure stands did not differ in pathogenicity (P = 0.42). In 2000, epidemic intensity was intermediate, mixture plots were 15.2% more diseased than the mean of component pure stands (P = 0.053), and populations from two of four mixtures were 152 and 156% more pathogenic than the mean of populations from component pure stands (P = 0.043 and 0.059, respectively). Mixture yields were on average 2.4 and 6.2% higher than mean component pure-stand yields in 1999 and 2000, respectively, but the differences were not statistically significant. The ability of mixtures challenged with M. graminicola to suppress disease appears to be inconsistent. In this system, host genotype mixtures evidently do not consistently confer either fitness benefits or liabilities on pathogen populations.