بعض الخصائص الحيوية للفطر Marssonina juglandis (Lib.)‎ Magnus مسبب مرض التبقع البني على الجوز

الملخص EN

This research was conducted in order to study the dynamics of development of the brown spot disease in walnuts, and bio-aspects of fungus causing the diseasey.

Results showed that the disease is wide spread, and it can be seen in the beginning of May on the surface of the lower leaves in the inner and lower parts of the trees.

The percentage and severity of disease increased and reached a peak in December (80.11%.

and 19.5% respectively).

Severely infected leaves dried-up and fell down from the beginning of May till the end of August.

Small un-ripe fruits were grown unusually, and most fruits dropped down before ripening.

Results also showed that, the activity of conidiospores in the field were high in May, June and July; medium in June and August; and weak in the other months of the year.

Nutrient elements activated conidiospores to germinate.

Conidiospores germinated within a narrow range of pH (6-10), and the optimum temperature for germination was 20º C.