Under field conditions, distribution (vertical and horizontal) of eleven nematode genera on three date-palm cvs. Barhi , Samani and Zaghlool. Seasonal fluctuation of Meloidogyne incognita, and its biological control on date-palm cv. Zaghlool were investigated during one year of 2012. Results indicated that all eleven nematode genera recovered were found in high densities at a depth of 30-50 cm for both types of distributions, whereas only three genera viz. Criconemoides , Tylenchus and Trichodorus were detected in low densities at depth over 50 up to 100 cm in the case of vertical. However, at depth of 50-100 cm only three genera e.g. Aphelenchus, Criconemoides and Tylenchus were recovered in low number in the case of horizontal. Meanwhile, seasonal fluctuation of M. incognita population (J2) showed generally high peaks on date - palm cvs. Zaghlool, Samani and Barhi soil in August 2012, where Zaghlool cultivar ranked first in this respect. M. incognita (J2) population increased gradually during July, August and September on tested cultivars, then decreased in November and December 2012. Regarding M. incognita integrated biological control on date-palm cv. Zaghlool, dual treatments gave better results than single one for both percent reduction of reproduction factor and percentage increase of crop yield (78.1 %), especially, Paecilomyces lilacinus + Datura stramonium treatment .
Results also indicated amount increase in concentration of total sugar, total phenol, reducing sugar and free phenols in date-palm cv. Zaghlool of dual treatment than the single one, where P. lilacinus plus D. stramonium ranked first , however, the opposite trend was recorded in the case of total amino acids.