|
|
|
INOCULUM SOURCES,
DISEASE INCIDENCE AND SEVERITY OF BACTERIAL BLACKLEG AND
SOFT ROT OF POTATO
HAFIZ FARHAD ALI1*, MUSHARAF AHMAD1,
MUHAMMAD JUNAID1, AYESHA BIBI1,ASAD ALI1, MUHAMMAD SHARIF1, BARKAT ALI2, KHALID NAWAB1
AND AMNA SADOZAI2
Abstract:
Comprehensive surveys
during spring, summer and fall, 2007-2009 were conducted in the major
potato-growing areas of KPK to record the incidence, severity and
distribution of blackleg and soft rot of potato caused by the different
subspecies of Erwinia. Maximum disease severity (40%) and disease incidence
(60-75%) was found in the spring and summer potato crop grown in
Abbottabad, Swat and Mardan, Pakistan. The frequencies of Erwinia
carotovora subsp. atroseptica (Eca), E. c. subsp.
carotovora (Ecc) and Erwinia chrysanthemi (Ech), based upon
the survey of 42 locations, were found to be 48%, 45%, and 7%,
respectively. Regarding soil, diseased plant debris and seed potatoes as
sources of inoculum for Eca, healthy plant material, potted
un-sterilized soil and healthy seed potatoes were inoculated with Eca,
kept in screen-house and monitored for changes in bacterial population
over a period of three months. It was found that seed potatoes were the
most important source of primary inoculum as the bacterial population
considerably increased in numbers throughout the monitoring period. The
bacterial population in the inoculated plant debris did decrease but the
rate of decline was quite slow and therefore, diseased plant debris
could be considered as a good source of primary inoculum for the
appearance of black leg disease in the next season.
1Khyber Pakhtunkhwa Agricultural University, Peshawar, Pakistan
2Agricultural Research Institute, Tarnab, Peshawar, Pakistan
*Corresponding
author E-mail:
hafizfarhad66@yahoo.com
|
|
|