Epidemiology and control of powdery mildew (podosphaera leucotricha (ell. and ev.)‎ salm.)‎ on apples in the uplands of Jordan

Abstract EN

A study was conducted to evaluate the epidemiology and effectiveness of different fungicides on suppression of powdery mildew infestation on apple in the main upland regions in Jordan during the period from April, 2002 to May, 2003 .

Two apple cultivars namely Golden Delicious and Starking were used in this experiments and planted in six locations including Amman, Madaba, Al-Yadodeh, Jerash (Jaba), Ajlun, and Anjarah.

Time of bud growing stages and symptoms of primary infection, as well as incidence, severity and seasonal development of disease were monitored during this investigation.

Sampled shoots were examined In seares for overwintering stages.

Also six different fungicides were tested for the efficacy toward powdery mildew.

Meteorological data revealed that different locations have different climatic conditions, so they have different patterns of disease development.

Symptoms of primary infection appeared first in the middle of April in Al-Yadodeh, Madaba, Amman, Ajlun and Anjarah that had relatively warmer weather, and finally appeared' at the beginning of May in Jaba, which was the coldest location.

Results showed that Podosphaera leucotricha was found between bud scales in August and remain viable during winter season.

Cleistothecia, a sexual stage of the fungus, was" also reportd for the first time in Jordan in the samples collected from Anjarah area.

Results of chemical control in Al-Yadodeh location showed that all tested fungicides had the capability to reduce disease development significantly compared to control.

Systhane and Bayfidan were the most effective fungicides resulting in the reduction of disease incidence and severity to 16.1% and 17.4%, respectively when used at the recommended rates.