Greenhouse and field microplot studies were conducted to compare soybean shoot and root growth responses to root penetration by Heterodera glycines (Hg) and Meloidogyne incognita (Mi) individually and in combination. Soybean cultivars Centennial (resistant to Hg and Mi), Braxton (resistant to Mi, susceptible to Hg), and Coker 237 (susceptible to Hg and Mi) were selected for study. In the greenh...

the population density and spatial distribution pattern of empoasca decipiens paoli were etermined in tehran area, iran, during 2004-2005 on four species of common bean phaseolus vulgaris (l.) var. talash, lima bean p. lunatus (l.) savi ex hassk. var. sadaf, rice bean p. calcaratus roxb. var. goli and cowpea vigna sinensis (l.) var. parastoo. the higher and lower mean population densities of e....

population density and spatial distribution of thrips tabaci lindeman on seven soybean varieties (williams, tellar, sahar, dpx, l17, sari and zane) and one genotype (ks3494) were studied in tehran region, during 2007. the highest population density of the thrips per leaf was recorded on dpx and on ks3494 (0.810.05 and 0.800.05, respectively). the lowest population density was observed on l17 ...

Root-knot nematodes (Meloidogynespp.) are the most important pests of vegetables, field crops, and ornamental plants. During our previous study, twenty eight okra cultivars were examined against resistance and Pusa Swami was ranked the most susceptible. The purpose of this study was to investigate the effects of increasing initial population density (Pi) of M. incognita on nematode reproduction...

Many bacteria utilize sophisticated regulatory systems to ensure that some functions are only expressed when a particular population density has been reached. The term 'quorum-sensing' has been coined to describe this form of density-dependent gene regulation which relies on the production and perception of small signal molecules by bacterial cells. As in many pathogenic bacteria the production...

iran is a large country with a total area of 1,645,000 square kilometers. the country’s population is estimated at about 31 millions. there is an uneven distribution of the population, varying from 2 to 50 per square kilometer. sixty per cent of the total population (18 millions) is living in nearly 66,000 small and large village’s scattered throughout the country. a total of 10,000 physicians ...

Custer and Hood soybean cultivars were inoculated with nine levels of Criconemoides simile ranging from 300 to 20,600 nematodes per plant. Rate of reproduction decreased as inoculum level was increased beyond 900-2,000 nematodes. Final population density was influenced by both composition and level of inoculum. There was an indication that substance(s). inhibitory to larvae, accumnlated in soil...

Management is an effective tool for increasing the productivity of Mongolian pine (Pinus sylvestris var. mongolica). This species has been widely planted in China, especially in sandy lands. However, optimization of management practices had not been fully explored. We established a system dynamic model to evaluate the effects of thinning and of manipulation of water supply on the productivity a...