حصر للفطريات المصاحبة لأعراض مرض اللفحة السوداء و تبقعات أوراق النخيل في منطقة الرياض

Abstract EN

The study area (Riyadh) was divided to 10 areas: Aloiaynah, Alwaseel and Ammariah, Aldereah, Almozahimeah, Dyrab, Alhaear, Alkharj, Malham and Benban, Horaimala and sadoos.

The survey result showed the presence of black scorch in all studied areas.

It was occurred most frequently in Almozahimeah area 72.2% , followed buy Alhaear area 60% then Dyrab area 35.1% , and it was least frequent in Alkharj area 3.8% .The causal agent of black scorch was identified as Chalara paradoxa.Leaf spots varied in shape and size in different areas.

Leaf spots represented 99% of all samples collected in Alwaseel and Ammariah , followed by Dyrab area 75.4% , then Almozahimeah area 61.5% , and it was the least in Horaimala area 13.3%.The following fungi were isolated from leaf spots: Phoma glomerata, Cladosporium cladosporiodes, Alternaria spp, Stemphylium bottryosum, Helminthosporium spp, Coniothyrium spp and Myrothecium roridum.The fungus Myrothecium roridum is recorded for first time in Saudi Arabia.

It was identified by British common wealth.

The symptom it causes occurred on the tip of leaflets as dead areas.

It starts as white color of the tips then changes to reddish brown then dies completely.

The fungus was present in three areas only: Aloiaynah , sadoos , and alkharj .

The highest occurrence was in Aloiaynah 11.9% then Sadoos 10% and the least in Alkharj 2.1%.

The study shows that the fungus Chalara paradoxa recorded highest on the variety Sheshi at Almozahimeah area 59.34% , then on variety Naptat Saif at Alhaear area 42.86% , on varieties Rashodiah and Sabbakah at Alwaseel and Alammariah 5.2% , on Suckariah it was recorded 13.12% and 12.85% at Dyrab and Almozahimeah, respectively.

It recorded lowest on Monaify at AlKharj area 0.09%.

The study showed the highest record of leaf spots fungi in Alwaseel and Alammariah 35% on Naptat Saif.

Followed by Monaify at same area 24.5%.