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41.
Z. Ngoko K.F. Cardwell W.F.O. Marasas M.J. Wingfield R. Ndemah F. Schulthess 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(9):893-902
The aim was to identify biological and physical factors responsible for reducing maize yield in Cameroon. Two surveys were conducted in 137 fields in two agroecological zones in 1995–1997. In the Humid Forest (HF), Bipolaris maydis, Stenocarpella macrospora, Puccinia polysora, Rhizoctonia solani and soil fertility were factors that reduced maize production in 1995 and 1996. In the Western Highlands (WHL), Cercospora zeae-maydis, and the interaction between soil fertility and maize variety were the most important constraints to maize production in 1996. In 1997, C. zeae-maydis, S. macrospora, physiological spot and stem borer damage (Busseola fusca) were negatively related to ear weight. The combination of these biological factors (diseases and insects), and the physical parameter of soil fertility were responsible for reducing maize yield in these selected benchmarks of Cameroon. Maximum potential yield reductions were estimated at 68% due to B. maydis and 46% due to S. macrospora, respectively, in the HF in 1995. In 1996, maximum potential yield reductions in the HF were estimated at 34%, 41% and 30% due to S. macrospora, P. polysora and R. solani, respectively. In the WHL, C. zeae-maydis had the potential to cause a yield reduction of 79% in 1996. In the WHL in 1997, the interaction between C. zeae-maydis and B. fusca, stem diseases and the physiological spot caused potential reductions of 52%, 34% and 39%, respectively. 相似文献
42.
对山西菜田捕食性食蚜蝇优势种及对菜蚜的控制效果进行了研究,菜田常见捕食性食蚜蝇有黑带食蚜蝇,大灰食蚜蝇,斜斑鼓额食蚜蝇,野食蚜蝇,四条小食蚜蝇,短翅细腹食蚜蝇6种,以黑带食蚜蝇种群数量最大,平均占全年发生总量的36.3%,通过对食蚜蝇产卵量,卵化率,幼虫期捕食量和羽化率测试,筛选出的黑带食蚜蝇,大灰食蚜蝇,斜斑鼓额食蚜蝇幼虫对菜蚜均有较强的捕食能力,其中黑带食蚜蝇为山西菜田菜蚜捕食性食蚜蝇优势种,用黑带食蚜蝇三龄幼虫对菜蚜进行防治试验,结果以1:180防效最佳,72h后控制效果达93.5%。 相似文献
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许多固氮树种速生丰产,萌生能力强,叶片,木屑含氮率较高,可为食用菌栽培提供理想原料,而且固氮树种在绿花荒山,保持水土,提高地力方面作用显著,以固氮树种发展短轮伐期食用菌专用林,具有较高的经济效益和生态效益,本文介绍了银合欢,黑荆,大叶相思,银荆,桤木,南洋楹和马占相思等在食用菌栽培上的应用概况,各地可因地制宜栽培合适的固氮树种作为食用菌专用林。 相似文献
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本文综述了对螟虫长距茧蜂的研究概况,包括该寄生蜂的主要生物学习性、对玉米螟自然寄生率及田间防治玉米螟效果等。 相似文献
50.
Hiromitsu Furuya Tsutomu Matsumoto Shin-ichi Fuji Hideki Naito 《Journal of General Plant Pathology》2003,69(2):115-119
Rice seedling growth, estimated by plant height and root development and discoloration, was better in pasteurized soil than
in unpasteurized soil obtained from a flooded rice field. Rice seedlings also grew better in sterilized soil modified by adding
roots harvested from the pasteurized soil than in soil modified by adding roots harvested from the unpasteurized soil. The
results demonstrate that seedling growth in the rice field soil was inhibited by soil microorganisms, even though no typical
symptoms such as seedling blight or damping-off appeared. Pythium aristosporum is suggested to be involved in the inhibition. Thus, it appears that inconspicuous restraint of rice seedling growth could
occur in soils of rice paddy fields.
Received: May 20, 2002 / Accepted: October 16, 2002
Acknowledgments The authors thank Dr. T. Ichitani, former professor at Osaka Prefectural University, for providing an isolate of Pythium aristosporum for comparison, and Mr. Mitsuaki Sato of Akita Prefectural College of Agriculture for technical assistance. 相似文献