EFFECT OF SALINITY ON ROOT ROT DISEASE OF DATE PALM AND ITS CONTROL WITH SPECIAL REFERENCE TO Phytophthora palmivora (BUTL.) AS A NEW CAUSAL PATHOGEN IN EGYPT.

Document Type : Original Article

Authors

1 Plant Pathology Res. Inst., Agriculture Research Center, Giza, Egypt

2 Central Laboratory for Date Palm Research & Development.

Abstract

Date palm (Phoenix dactylifera L.) plantation cultivated in the new reclaimed
lar.d under different levels of soil and water salinity in some regions was affected by
root rot disease. The main symptoms are stunting, malformation of the new leaves
only; reduction in vegetative growth, drying of some outer leaves and some rachides
appears free from pinnae. Phytop < /em>hthora palmivora was recorded for the first time in
Egypt as the main causal pathogen of root rot disease. On the other hand, Fusarium
moniliforme was less frequent and pathogenic one. Effect of solute potential on
disease incidence revealed that increasing of irrigation water salinity increased the
root rot caused by Ph. palmivora in all salt concentrations used meanwhile, no
significant effect was found in case of F. moniliforme. In general, results indicate that
high salinity levels may be a factor in root rot development leading to higher disease
incidence. Evaluation of different fungicides on disease control revealed that Topsin M
70 and Tachlq: ren were the most effective fungicides against both tested fungi in
vitro. Also, un: r field conditions both fungiCides gave the same trend of laboratory
screening aile'. 'ere the best for controlling root rot recorded the highest percent of
decrease in dis( ase incidence.