Influence of soil temperature and moisture on seasonal variation of three plant-parasitic nematodes associated with apple in Swat, Pakistan.
The effect of soil temperature and moisture on the population density of Helicotylenchus pseudorobustus, Paratylenchus projectus and Xiphinema rivesi was investigated in an apple orchard in Swat, Pakistan. The three species constituted about 70% of the total nematode density in apple rhizosphere. The population density of the nematodes, in general, was relatively low at cold temperature during winter and greater at higher temperature during the summer and showed a marked degree of linear relationship with soil moisture, though this relationship was not as strong as with soil temperature. The possible implications of nematode population fluctuations and their causes are discussed.