白粉

The physiological strains of Erysiphe graminis were determined in 1999～2000 and the changes of strain groups were analyzed.

对1999～2000年小麦白粉病菌的生理小种进行了鉴定，并分析了小种种群的变化。

Powdery mildew is a serious disease of wheat in China, which is caused by the fungus Erysiphe graminis DC.

由白粉菌Erysiphe graminis DC引起的小麦白粉病是我国小麦生产中的严重病害。

So BTH and SA could effectively induce SAR of muskmelon against Erysiphe cucurbitacearum.

诱导剂本身对甜瓜白粉病菌分生孢子萌发及菌丝生长无明显影响。

In order to understand the validity of the resistant genes to wheat powdery mildew in Shanxi province, in greenhouse condition, cleistothecia released ascospores were used to infect wheat seedling. The frequencies of virulence genes for 166 isolates of Erysiphe graminis f. sp. tritici from different ecological areas of Shanxi province were tested.

为明确小麦白粉病抗性基因在山西省的有效性，在温室条件下，通过闭囊壳释放子囊孢子侵染麦苗发病，利用28个已知抗病基因品种对分离自山西省不同生态区的166个小麦白粉病菌株进行了毒性基因频率测定。

Erysiphe graminis ; physiological strain ; determination ; RAPD analysis

小麦白粉病菌；生理小种；鉴定； RAPD分析

In this research, we attempted to construct an SSH (suppression subtractive hybridization) library using the leaves of wild H. villosa (Gh21) inoculated by Erysiphe graminis and its susceptible EMS-induced mutant M14S with no inoculation.We screened 218 positive clones in the SSH library, and gained 60 ESTs after sequencing.

本研究应用抑制性消减杂交技术，以野生型簇毛麦(Gh21)及其感病突变体(M14S)为材料，建立白粉菌诱导的叶片的SSH文库，获得218个阳性克隆，对其中部分克隆测序，获得60个EST序列。

The results showed that virulence frequency of V4a、V4b、V13、V20、V21、VXBD、V2+6、V4+8、V2+Mli、V4b+Mli、V5+6、V1+2+9 were 3.6%~29.7%, Pm4a, Pm4b, Pm13, Pm20, Pm21, PmXBD, Pm2+6, Pm4+8, Pm2+Mli, Pm4b+Mli, Pm5+6, Pm1+2+9 were effective resistant genes to Erysiphe graminis f. sp. tritici and may be applicated as resistant parents; Virulence frequency of V1、V2、V3a、V3d、V3f、V6、V17、V19、V2+Ta were 38.6%~79.4%, The validity of Pm1、Pm2、Pm3a、Pm3d、Pm3f、Pm6、Pm17、Pm19、Pm2+Ta had decreased; Virulence frequency of V3b、V3c、V3e、V5、V7、V8 were 92.5%~98.7%, Pm3b、Pm3c、Pm3e、Pm5、Pm7、Pm8 had no applicable value in breeding if they were utilized as the only resistant sources.

结果表明，毒性基因V4 a、V4 b、V13、V20、V21、VXBD、V2+6、V4+8、V2+Mli、V4 b+Mli、V5+6、V1+2+9的出现频率为3.6%29.7%，其对应抗性基因Pm4 a、Pm4 b、Pm13、Pm20、Pm21、PmXBD、Pm2+6、Pm4+8、Pm2+Mli、Pm4 b+Mli、Pm5+6、Pm1+2+9为目前山西省小麦白粉病菌的有效抗病基因，可供转育利用；毒性基因V1、V2、V3 a、V3 d、V3 f、V6、V17、V19、V2+Ta的出现频率为38.6%79.4%，其对应抗性基因Pm1、Pm2、Pm3 a、Pm3 d、Pm3 f、Pm6、Pm17、Pm19、Pm2+Ta的利用价值已下降；毒性基因V3 b、V3 c、V3 e、V5、V7、V8的出现频率为92.5%~98.7%，其对应抗性基因Pm3 b、Pm3 c、Pm3 e、Pm5、Pm7、Pm8单独使用无利用价值。

The result suggests that the plant was infected with geminivirus. Stem scions from the plant were graft-inoculated to I. purpurea. Three weeks later, the indicator developed symptoms of leaf curling and interveinal chlorosis. The geminivirus can be transmitted by whitefly.

实验表明该染毒材料嫁接到指示植物牵牛上三周后牵牛植株产生卷叶和叶片变黄的症状；病毒可由白粉虱传播，初步认定该病毒是菜豆金色花叶病毒属的甘薯卷叶病毒(sweet potato leaf curl virus，SPLCV)，将其命名为SPLCV-CN。

The results showed that extracts from 8 plant species were more inhibitory to S.fuliginea than the others,with EC50 lower than 0.5%.Among the 8 extracts,the preventive effects of 6 plant extracts except Artemisia capillaries and Portulaca oleracea were higher than their curative effects.The preventive effects of 1.25%extract from the 8 plants were higher than that(74.42%) of 100 μg/mL triadimefon.1.25% extract from Cortex phellodendri,P.cablin,Portulaca oleracea,Fructus cnidii and Kadsura japonic exhibited the curative effect of as high as 82% to S.fuliginea,higher than that(78.89%) of 100 μg/mL triadimefon.

其中水蓼、川黄柏、连翘等8种植物提取物对黄瓜白粉病菌具有较好抑制作用，EC50值均小于0.5%，除茵陈和马齿苋外，其他6种植物提取物对黄瓜白粉病的保护效果均高于治疗效果。8种植物提取物在1.25%浓度下对黄瓜白粉病的保护效果均高于化学药剂三唑酮100μg/mL(74.42%)；1.25%的川黄柏、广藿香、马齿苋、蛇床子、南五味子提取物对黄瓜白粉病的治疗效果达到82%以上，高于三唑酮100μg/mL(78.89%)，说明在黄瓜白粉病发生之前或初期使用这8种植物提取物能够达到较好的防治效果。

The dominating pests of vegetable are Trialeurodes vaporariorum,Liriomyza sativae, Polyphagotarsonemus latus in greenhouse.

阐述了温室白粉虱、美洲斑潜蝇、菜蚜、根蛆和茶黄螨等温室蔬菜害虫的发生与为害，并提出了无公害治理措施。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。