13种杀菌剂对水稻胡麻叶斑病防效研究

为科学合理选用防治水稻胡麻叶斑病的杀菌剂, 采用菌丝生长速率法, 测定了13种杀菌剂对水稻胡麻叶斑病菌的毒力, 对毒力较好的药剂开展盆栽防效试验?结果表明:测试的13种药剂中, 70%丙森锌WP?325 g/L苯甲·嘧菌酯SC?75%肟菌·戊唑醇WG?23%醚菌·氟环唑SC?50%福美双WP?400 g/L氯氟醚·吡唑酯SC对病原菌菌丝生长表现出明显的抑制作用, 不同浓度处理的抑制率均达到60%以上, 最高可达100%; 各药剂对水稻胡麻叶斑病菌的毒力差异显著, 325 g/L苯甲·嘧菌酯SC对水稻胡麻叶斑病菌的毒力最高, EC50为0.000 1 μg/mL; 毒力较高的药剂有23%醚菌·氟环唑SC?75%肟菌·戊唑醇WG?50%咪鲜胺锰盐WP?70%丙森锌WP?50%福美双WP?9%吡唑醚菌酯CS?30%苯甲·丙环唑EC?400 g/L氯氟醚·吡唑酯SC?250 g/L嘧菌酯SC, EC50为0.017 1~2.027 0 μg/mL; 15%井冈霉素SP?40%稻瘟灵EC?75%三环唑WP的毒力较低, EC50为11.265 4~88.283 5 μg/mL?人工接种盆栽防效试验结果显示, 70%丙森锌WP对水稻胡麻叶斑病的预防效果最好, 使用剂量945~1 575 g/hm2 的防效均在72.00%以上; 325 g/L苯甲·嘧菌酯SC的治疗效果最好, 使用剂量195~292.5 g/hm2的防效均在74.00%以上, 这两种药剂可作为目前水稻胡麻叶斑病田间应急防控的首选药剂, 二者作用机制不同, 建议轮换使用?     

吡唑醚菌酯与氟环唑复配对小麦叶锈病的防治效果及对小麦的安全性

为筛选适用于小麦叶锈病防治的化学药剂,本研究选取吡唑醚菌酯和氟环唑及二者不同比例复配组合,采用喷雾接种法,测定了吡唑醚菌酯和氟环唑单剂及其不同复配比例在作为保护剂使用时对小麦叶锈病的室内防治效果,并测定了室内筛选确定的最佳比例复配药剂对小麦的安全性及对小麦叶锈病的田间防治效果。室内防效试验显示：吡唑醚菌酯、氟环唑及二者不同比例复配对小麦叶锈病病斑扩展有强烈的抑制作用,其中吡唑醚菌酯的抑制作用更强,其EC₅₀值为0.01μg/mL。联合毒力评价表明：所有复配组合均表现出协同相加作用,吡唑醚菌酯·氟环唑质量比50∶133复配时增效系数(SR)最大,为1.50。室内及田间防治试验表明：在所设浓度梯度范围内,防效与浓度呈正相关;在有效成分120 g/hm²剂量下,26%吡唑醚菌酯·氟环唑悬浮剂(SC)的田间防效为85.12%,优于各自单剂处理。安全性评价结果显示：所有处理均能保证不同品种小麦正常生长,未发生药害现象。研究表明,吡唑醚菌酯·氟环唑复配对小麦叶锈病有很好的防治效果,可为生产上防治小麦叶锈病和科学用药提供理论依据。     

进口杀菌剂防治玉米中后期病害效果

玉米中后期是玉米病害的多发期和高发期,对玉米产量和质量构成严重威胁。试验筛选验证当前主要防治病害的进口杀菌剂对玉米中后期病害的防控效果。试验结果表明,进口杀菌剂30%苯甲·丙环唑、30%苯甲·丙环唑、10%苯醚甲环唑、18.7%丙环·醚菌酯、25%吡唑醚菌酯和丙环唑对玉米中后期的玉米大小斑病、弯孢霉菌叶斑病、纹枯病、褐斑病的防效良好,产量增幅较大,且10%苯醚甲环唑和25%吡唑醚菌酯防效与产量高于其他三种菌剂,更值得推广,可根据每种杀菌剂的性价比进行筛选使用。     

防治珍珠李叶枯病的药剂筛选

采用菌丝生长速率法测定了12种药剂对珍珠李叶枯病主要病原胶孢炭疽菌(Colletotrichum gloeosporioides)的抑制作用,并进行田间施药防病试验,调查各药剂的实际防效。结果表明,氟硅唑·咪鲜胺、咪鲜胺和苯醚甲环唑·醚菌酯对病原菌的室内毒力较高,EC50均低于0.03μg/mL;50%咪鲜胺可湿性粉剂、5%氨基寡糖素水剂、325 g/L苯醚甲环唑·醚菌酯悬浮剂、10%苯醚甲环唑水分散粒剂和250 g/L吡唑醚菌酯乳油的田间防病效果较好,均在75%以上。     

不同杀菌剂对小麦白粉病的田间防效

为筛选防治小麦白粉病高效、低毒的杀菌剂,在小麦白粉病发生初期,分别使用20%三唑酮乳油、430g/L戊唑醇悬浮剂、5%己唑醇悬浮剂、30%吡唑醚菌酯悬浮剂、0.5%大黄素甲醚水剂、1%蛇床子素水乳剂、10%多抗霉素可湿性粉剂共计7种不同类型的杀菌剂进行田间施药试验。喷药10d后调查各处理区发病情况,并于小麦成熟后测产。试验结果显示,供试杀菌剂中,以5%己唑醇悬浮剂对小麦白粉病的病指防效最高,达到98.95%,其处理区小麦增产率也最高,为20.79%;0.5%大黄素甲醚水剂和30%吡唑醚菌酯悬浮剂防效次之,分别为94.37%和93.57%;20%三唑酮乳油防效最差,但也达到85.55%。供试药剂均对小麦白粉病表现出较高防效。     

7.5%氟环唑乳油对香蕉叶斑病毒力测定与防治试验

香蕉叶斑病在华南香蕉产区夏秋生长季节大量发生,严重危害香蕉功能叶片。7.5%氟环唑乳油是防治香蕉叶斑病的新型杀菌剂。室内毒力测定表明,7.5%氟环唑乳油对香蕉尾孢菌的抑菌效果明显,25 μg/mL和50 μg/mL的抑菌效果分别为91.73%和93.31%。2004-2005年田间药效试验表明,在香蕉营养生长期使用7.5%氟环唑乳油 1 000、750、500、250倍液喷药3次,对香蕉叶斑病的防效为66.25%～84.37%,其中250倍液防效达82.48%～84.37%,显著优于对照药剂25%丙环唑乳油1 500倍液的防效,值得在生产上推广使用。     

吡唑醚菌酯·代森联防治柑桔炭疽病效果评价

利用吡唑醚菌酯·代森联等五种杀菌剂进行防治柑桔炭疽病田间药效试验,结果表明,供试各药剂对柑桔炭疽病均有一定的防效;供试药剂吡唑醚菌酯·代森联有效成分800mg/L五次施药,叶片防效达到(97.88±1.90)%及果实贮藏60d防效为91.18%的效果,表现较好的持效性。     

12种杀菌剂防控莴笋菌核病效果研究

为筛选对莴笋菌核病有较好防效的杀菌剂,采用菌丝生长速率法测定了12种杀菌剂对莴笋菌核病病菌的毒力,对其中5种毒力较强的杀菌剂进行了田间防效验证。咪鲜胺、戊唑醇、苯醚甲环唑、嘧菌酯、抑霉唑、多·福和菌核净对莴笋菌核病病菌的室内毒力较强,EC_(50)分别为0.0136、0.0263、0.2092、0.2880、0.8806、1.1088、1.3635μg/mL;上述5种药剂对莴笋菌核病的田间防效分别为85.89%、82.39%、75.24%、71.81%和64.73%。在生产上,推荐轮换使用咪鲜胺、戊唑醇或苯醚甲环唑、嘧菌酯3类药剂,可提高对该病的田间防效,并延缓病菌抗药性的产生。     

5种不同药剂防治小麦赤霉病田间药效试验

作者开展了40%咪铜·氟环唑SC等5种杀菌剂对小麦赤霉病的田间防效试验。结果表明,80%戊唑醇WG、80%多菌灵WP、40%咪铜·氟环唑SC、15%丙唑·戊唑醇SC和325g/L苯甲·嘧菌酯SC对小麦赤霉病的防效分别达到73.15%、60.07%、83.56%、71.81%和56.38,以40%咪铜·氟环唑SC防治效果最好。     

6种杀菌剂防治草莓白粉病的田间药效评价

探索乙嘧酚、醚菌酯、醚菌+啶酰菌、唑醚+氟酰胺、苯醚甲环唑+醚菌酯、粉唑醇6种杀菌剂对草莓白粉病的防治效果及对草莓的安全性,为药剂的推广应用提供依据。参照《农药田间药效试验准则》要求,进行了防治草莓白粉病的田间试验,比较不同药剂对草莓白粉病的防病效果。试验的醚菌+啶酰菌、唑醚+氟酰胺、苯醚甲环唑+醚菌酯、醚菌酯4种杀菌剂对草莓白粉病的防治效果优良,达85%左右;乙嘧酚和粉唑醇的防效次之,乙嘧酚中、高剂量防效高于粉唑醇,低剂量防效与粉唑醇相当。醚菌·啶酰菌、唑醚·氟酰胺、苯醚甲环唑+醚菌酯、醚菌酯这4种杀菌剂防效优良,建议在生产上推荐轮换使用。     

Effects of various classes of herbicides on four species of algae

Chlorella pyrenoidosa, Chlorococcum sp., Lyngbya sp., and Anabaena variabilis were cultured in Bold's basal medium. They were treated with 0.1, 1.0, and 10 μM concentrations of 2-chloro-2′, 6′-diethyl-N-(methoxymethyl)acetanilide (alachlor), 2-chloro-4-(ethylamino)-6-(tert-butyl-amino)-s-triazine (terbuthylazine), 2-sec-butyl-4,6-dinitrophenol (dinoseb), 1,1-dimethyl-3-(α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine) (profluralin), 2, 4-bis(isopropylamino)-6-(methylthio)-s-triazine (prometryne), and (2,4-dichlorophenoxy)acetic acid (2,4-D). Growth of all algal species tested was markedly reduced by the triazines. Alachlor, dinoseb, and fluometuron inhibited growth of some algae at higher concentrations while 2,4-D and profluralin did not inhibit growth at the concentrations tested. Photosynthesis was greatly inhibited by the triazines, even at the 0.1 μM concentration. Fluometuron was very toxic to the blue-green algae but had less effect on the green algae tested. Lyngbya was most susceptible to photosynthesis reduction by the herbicides. The concentrations of herbicides tested had little effect on respiration of the algae species. It appears that effects on algal growth were due primarily to inhibition of photosynthesis rather than to other metabolic processes.     

Mode of action of meturine

The effect of meturine on the light processes of photosynthesis was studied.Meturine is a herbicide for weed control in potato and cotton crops. It is a N-phenyl—N-hydroxy—N′-methylurea.The experiments were carried out on isolated pea and spinach chloroplasts.When examining photosystem I, reduced DPIP was used as an electron donor, whereas methyl-viologen served as an electron acceptor. When examining photosystem II, DPIP represented the electron acceptor.The obtained experimental results have pointed to the absence of the effect of meturine upon the photoreaction I.Unlike N-phenyl—N′, N′-dimethylureas (CMU, DCMU) meturine has been a very weak inhibitor of photoreaction II.The authors explain the photoreaction II inhibition of chloroplasts from plants treated with herbicidal doses of meturine by conversion of N-phenyl—N-hydroxy—N′-methylurea into Hill reaction inhibitor(s). N-Phenyl—N′-methylurea can be one of such meturine metabolites.Meturine herbicidal action is accounted for by meturine transformation into Hill reaction inhibitor(s) in the plant tissues.     

Effectiveness of Coniothyrium minitans and Trichoderma atroviride in suppression of sclerotinia blossom blight of alfalfa

The effects of the mycoparasites Coniothyrium minitans and Trichoderma atroviride on the suppression of alfalfa blossom blight caused by Sclerotinia sclerotiorum were evaluated under indoor and field conditions. When T. atroviride (9·0 × 10⁴ conidia/floret) + S. sclerotiorum (6·0 × 10³ ascospores/floret) or C. minitans (9·0 × 10⁴ conidia/floret) + S. sclerotiorum (6·0 × 10³ ascospores/floret) were applied to detached young alfalfa florets, T. atroviride effectively inhibited saprophytic growth of S. sclerotiorum, whereas C. minitans showed no inhibition under the same conditions. When T. atroviride (6·9 × 10⁴ conidia/floret) + S. sclerotiorum (6·0 × 10³ ascospores/floret) or C. minitans (6·9 × 10⁴ conidia/floret) + S. sclerotiorum (6·0 × 10³ ascospores/floret) was applied to young alfalfa petals in vivo just after pollination, the percentage of pod formation was higher for T. atroviride+S. sclerotiorum than that for C. minitans+S. sclerotiorum, and the percentage of pod rot was lower for T. atroviride+S. sclerotiorum than that for C. minitans+S. sclerotiorum. However, when they were applied to senescent petals attached to developing pods of alfalfa at 9·2 × 10⁴ conidia/floret together with S. sclerotiorum at 4·5 × 10³ ascospores/floret at 14 days after pollination, C. minitans was more effective than T. atroviride in suppressing sclerotinia pod rot and seed rot of alfalfa. Field experiments showed that three applications of C. minitans (5·4 × 10⁶ conidia mL⁻¹) or T. atroviride (5·4 × 10⁶ conidia mL⁻¹) at a 7-day interval to blossoms of alfalfa effectively suppressed sclerotinia pod rot in two out of three annual trials. Coniothyrium minitans effectively suppressed sclerotinia seed rot in all three years, whereas T. atroviride was not effective against seed rot in any of the trial years. The efficacy of C. minitans was not significantly different (P > 0·05) from benomyl (250 µg ai mL⁻¹). This study suggests that C. minitans has potential as a biocontrol agent to control blossom blight of alfalfa caused by S. sclerotiorum.     

Biological Control of Sclerotinia Diseases of Rapeseed by Aerial Applications of the Mycoparasite Coniothyrium minitans

Indoor and field experiments were conducted to evaluate the efficacy of applying the mycoparasite Coniothyrium minitans to the aerial parts of rapeseed plants at the flowering stage to control sclerotinia diseases caused by Sclerotinia sclerotiorum. Under controlled conditions, a petal inoculation technique was used to determine the effect of conidial suspensions of C. minitans on suppression of sclerotinia leaf blight. Results showed that C. minitans was effective in inhibiting infection initiated by ascospores of S. sclerotiorum on flower petals by restricting mycelial growth of the pathogen. Suppression of lesion development was related to the conidial concentration of C. minitans, with larger lesions at low concentration (5×10³conidia ml⁻¹), but smaller lesions at high concentration (5×10⁴ conidia ml⁻¹ or higher). When C. minitans-treated rapeseed leaves were inoculated with mycelia of S. sclerotiorum, C. minitans failed to prevent infection of leaves, but caused a significant reduction in number of sclerotia produced on the diseased leaves. No significant difference in efficacy was detected between the two isolates of C. minitans, LRC 2137 and Chy-1, on the two rapeseed cultivars, Westar (spring type) and Zhongyou 821 (winter type). Results of field trials showed a significant reduction of stem rot of rapeseed in four (1997, 1999, 2003 and 2004) out of five years by aerial application of C. minitans, compared with controls. No significant difference in suppressive efficacy was observed between the treatments of C. minitans (10⁶ conidia ml⁻¹), C. minitans (10⁶ conidia ml⁻¹) + benomyl (50 μg ml⁻¹) and benomyl (100 μg ml⁻¹) in 2003, and between the treatments of C. minitans (10⁶ conidia ml⁻¹), C. minitans (10⁶ conidia ml⁻¹) + vinclozolin (100 μg ml⁻¹) and vinclozolin (500 μg ml⁻¹) in 2004. Sclerotia of S. sclerotiorum collected from diseased plants in plots treated with C. minitans in 1999, 2000 and 2003, or with C. minitans + benomyl in 2003 were infected by C. minitans at frequencies ranging from 21.3 to 54.5%. This study concludes that aerial spraying of C. minitans is an effective method for controlling sclerotinia diseases of rapeseed.     

The mechanism of fungistatic action of sec-butylamine: I. Effects of sec-butylamine on the metabolism of hyphae of Penicillium digitatum

Growth of Penicillium digitatum was inhibited after a 40-min incubation in a culture medium containing 0.5 mM sec-butylamine, and the dry weight of the hyphae was 50% of the control value after 180 min. Respiration of the hyphae was reduced 13% after a 20-min contact with 0.5 mM sec-butylamine but this treatment did not influence the uptake of amino acids, glucose, or phosphate nor intensify the efflux of ³³P- or ¹⁴C-labeled metabolites from the cells. The syntheses of cell walls and total lipids were inhibited 20–30% after a 90-min incubation with sec-butylamine, and nucleic acid synthesis was reduced to about 50% of the control value at this time. sec-Butylamine inhibited the incorporation of labeled carbon from [¹⁴C]glucose into the protein fraction of the hyphae to a greater degree than ¹⁴C derived from labeled proline, lysine, or leucine. These observations suggested that sec-butylamine interfered primarily with the intermediary metabolism of glucose rather than inhibiting a later stage of macromolecule synthesis. Hyphae incubated with [¹⁴C]glucose and sec-butylamine accumulated pyruvic acid to a level seven times greater than in control hyphae. Furthermore, sec-butylamine strongly inhibited ¹⁴CO₂ evolution from hyphae metabolizing [¹⁴C]pyruvate whereas CO₂ derived from acetate or glucose after a 45-min incubation was only slightly reduced by sec-butylamine. These observations implicate pyruvate oxidation as the primary site of sec-butylamine action in young hyphae of P. digitatum.     

混料设计在辣椒不同类型氮肥配比试验研究中的应用

采用田间试验,研究了混料设计中的单形重心设计在辣椒控释尿素、普通尿素配肥上的应用,测定了辣椒的产量及其构成,配置了各因子的产量回归方程,解析寻优,对肥料效应及经济效益进行了分析.结果表明,三种氮肥比例为普通尿素U=0.20～0.30,控释尿素D60(控释期60天)=0.40～0.60,控释尿素D30(控释期30天)=0.20～0.40(换算为纯氮实际用量U=150.0～225.0 kg/hm2,D60=300.0～450.0 kg/hm2,D30=150.0～300.0 kg/hm2)的方案,预测最高产量可达85.0 t/hm2.控释尿素D30-D60两者配合施用、普通尿素与控释尿素D30-D60三者配合施用均能显著提高辣椒产量,比普通尿素分别增产24.40、28.26 t/hm2,增产率分别为42.0%和49.0%,产量差异均达极显著水平.施肥效应以D30-D60混合最高,为20.88 t/hm2,达极显著水平.经济效益分析表明,U-D30-D60处理施肥利润为2.440万元/hm2,氮素利用率最高,为60.1%.普通尿素与两种控释尿素按一定比例混合施用有利于提高辣椒产量和增加农民的经济收入.     

Effects of different temperature treatments on dormancy of sclerotia of ten isolates of Sclerotium cepivorum

The variability of dormancy of sclerotia of ten isolates ofSclerotium cepivorum was investigated. Of all isolates tested, the freshly harvested sclerotia were dormant. After drying for 48 hours the sclerotia of six isolates were able to germinate, two isolates stayed dormant and two isolates were infested by hyperparasitic fungi. After storage in soil at 5°C or 20°C, the sclerotia of the different isolates exhibited considerable differences in respect to germination capability, but all isolates showed highest germination after a treatment of 8 weeks at 20°C followed by 8 weeks at 5°C. The sclerotia of all isolates showed an increased capacity to germinate withoutAllium extracts at 10°C after pretreatment at 30°C for 28 days.     

7种林木植物对华北大黑鳃金龟取食和繁殖的影响

为明确华北大黑鳃金龟Holotrichia oblita(Faldermann)的嗜食植物,优化其室内人工饲养技术及为诱虫植物提供候选材料,以花生叶片为对照,研究了7种林木植物叶片对华北大黑鳃金龟取食和繁殖的影响。结果表明,华北大黑鳃金龟对8种植物日均取食量由高到低依次为金叶女贞、刺槐、核桃、榆树、花生、柳树、香椿、毛白杨,其中金叶女贞、香椿和毛白杨与花生间有极显著差异,金叶女贞与刺槐、核桃、榆树间无显著差异;单雌产卵量由高到低依次为金叶女贞、柳树、核桃、香椿、花生、榆树、毛白杨、刺槐,其中金叶女贞、柳树、核桃、刺槐与花生间有极显著差异,而金叶女贞与柳树间无显著差异。研究表明,饲养华北大黑鳃金龟成虫适宜饲料植物为金叶女贞,日均取食量最高为4.70 g,产卵期最长为56.00 d,单雌产卵量最多为58.88个,其次为核桃和柳树。     

Antifungal mode of action of triforine

Rapidly growing mycelia of Aspergillus fumigatus treated with 10 μg/ml triforine (N,N′-bis-(1-formamido-2,2,2-trichloroethyl)-piperazine) showed little or no inhibition in dry weight increase prior to 2 h. By 2.5–3 h, triforine inhibited dry weight increase by 85%. The effects of triforine on protein, DNA, and RNA syntheses corresponded to the effect on dry weight increase both in time of onset and magnitude. Neither glucose nor acetate oxidation were inhibited by triforine.Ergosterol synthesis was almost completely inhibited by triforine even in the first hour after treatment. Inhibition of ergosterol synthesis was accompanied by an accumulation of the ergosterol precursors 24-methylenedihydrolanosterol, obtusifoliol, and 14α-methyl-Δ^{8, 24 (28)}-ergostadienol. Mycelia treated with 5 μg/ml of triarimol (α-(2,4-dichlorophenyl)-α-phenyl-5-pyrimidinemethanol) also accumulated the same sterols as well as a fourth sterol believed to be Δ^{5, 7}-ergostadienol.Identification of 4,4-dimethyl-Δ^{8, 24 (28)}-ergostadienol in untreated mycelia indicates that the C-14 methyl group is the first methyl group removed in the biosynthesis of ergosterol by A. fumigatus. The lack of detectable quantities of 4,4-dimethyl-Δ^{8, 24 (28)}-ergostadienol in triforine or triarimol-treated mycelia and the accumulation of C-14 methylated sterols in treated mycelia suggests that both fungicides inhibit sterol C-14 demethylation. The accumulation of Δ^{5, 7}-ergostadienol in triarimol-treated mycelia further implies that triarimol also inhibits the introduction of the sterol C-22(23) double bond.Two strains of Cladosporium cucumerinum tolerant to triforine and triarimol were also tolerant to the fungicide S-1358 (N-3-pyridyl-S-n-butyl-S′-p-t-butylbenzyl imidodithiocarbonate).     

温度对小麦矮腥黑穗病菌冬孢子萌发的影响

温度对小麦矮腥黑穗病菌冬孢子萌发影响的试验结果表明,TCK冬孢子在-2～12℃范围内都可以萌发,5℃为最佳萌发温度。同一分离菌冬孢子在不同温度处理的萌发特性和萌发率有差异;不同分离菌冬孢子在相同温度下的萌发特性和萌发率有很大差异。在5℃下5个分离菌中,冬孢子萌发起始时间最短的为15 d,最长为35 d,培养60 d时分离菌T_t1、T_t2、T_y、T_m和T_u冬孢子的萌发率分别为86.4%、23.9%、23.3%、44.3%和81.0%。根据分离菌T_t2不同温度下培养50 d时的萌发率,建立了萌发率(Y)与温度(X)的模型为Y=0.150 8 exp[-0.02949(X-4.957 6)]2,此结果为TCK的风险评估提供了基础数据。