دراسة بعض الخصائص البيولوجية للفطر Spilocaea oleagina المسبب لمرض عين الطاووس في أوراق الزيتون

Abstract EN

The appcarancc of peacock leaf spot disease causcd by Cycloconium oleaginum in the Setif region (east of Algeria) was found to be severe in spring and late autumn until early winter and very mild from early July until the middle of November Infection on the lower parts was more severe than on the upper part of the trees.

Damage on the leaves facing north was much more than on the ones facing south Production of conidia in the leaf spots was found to be high in spring and late autumn but very limited in summer and early autumn.

Temperature ranging from 15 to 18°C were found optimal for the growth of the fungus A reduction in growth was noticed at 3°C .

5°C and 25°C with complete growlh inhibition at 30°C .

Results obtained suggest that the dead leaves do not play a role in new infections and the role of the remaining spots on the tree during summer is of little importance.

Four periods of infection of new growth was noticed in the Setif region.

The first, during late spring, w here new leaves of young shoots were found infectcd During this period inoculum remains hidden until late autumn The second infection period occurs in autumn following rainfall The third, in late autumn-early winter and is characterized by the occurrence of new leaf spots which arc usually concentrated on the lowest pair of newly grown leaves.

The fourth period of infection occurs during early spring and is the most important.

The infectcd leaves of this period represent the source of inoculum for all the above mentioned three infection periods.