BIOLOGICAL CONTROL OF SCLEROTINIA SCLEROTIORUM, THE CAUSAL AGENT OF WHITE BASAL ROT DISEASE OF BEANS (PHASEOLUS VULGARIS L.)
MANAR MAGDY MOHAMED NABWY KHATER;
Abstract
6.1. Isolation, purification and identification
White mold, caused by S. sclerotiorum (Lib.) de Bary, is a destructive yield limiting disease of common bean (Phaseolus vulgaris L.) in Egypt. Forty eight isolates of Sclerotinia sp. were isolated from diseased bean tissues taken from 9 geographical regions at Al-Behaira, Alexandria and Assiut governorates during winter season 2008. Isolation processes yielded a 48 of isolates related to the genera of Sclerotinia sp. The obtained isolates were, then identified as S. sclerotiorum.
Frequency of the total isolates, isolated from basal stems, pods and seeds parts were estimated for both isolation techniques in all regions of the three tested governorates. Generally, total number of .isolates, recovered from plate agar isolation technique was higher than that of blotter technique. Total No. of isolates recovered from stems was higher than those of any of the tested bean parts.
6.2. Pathogenicity tests
The pathogenicity studies showed that the tested bean cultivars (Bronco, Contender, Giza 6 and Nebraska) varied in disease incidence. Contender bean cultivar was more resistant than other cultivars. Whereas, the more virulent Sclerotinia isolates were S5 and S6.
6.3. Histopathological invistigations
Histopathological studies were carried out in order to investigate and confirrp the modes of penetration of common bean plants with S. sclerotiorum and further histological deviations due to fungal invasion of different host tissues by u ing paraffin and electron microscope (TEM & SEM) methods.
Histology investigation of seedlings bean hypocotyls artificial inoculated with S. sclerotiorum after 24, 48, 72 and 96 hours after inoculation. Sections of samples were investigated by using either paraffin or electron microscope (SEM & TEM) methods.
6.3.1. Light microscope examinations
The penetration of bean seedlings was occurred during the first 48 hours after inoculation, through the epidermis and the outer layer of the cortex.
After 72 hours of inoculation, damage was extended deeper into the cortical cells. Infection took place inter-,and interacellularly after 96 hours more damage was occurred.
White mold, caused by S. sclerotiorum (Lib.) de Bary, is a destructive yield limiting disease of common bean (Phaseolus vulgaris L.) in Egypt. Forty eight isolates of Sclerotinia sp. were isolated from diseased bean tissues taken from 9 geographical regions at Al-Behaira, Alexandria and Assiut governorates during winter season 2008. Isolation processes yielded a 48 of isolates related to the genera of Sclerotinia sp. The obtained isolates were, then identified as S. sclerotiorum.
Frequency of the total isolates, isolated from basal stems, pods and seeds parts were estimated for both isolation techniques in all regions of the three tested governorates. Generally, total number of .isolates, recovered from plate agar isolation technique was higher than that of blotter technique. Total No. of isolates recovered from stems was higher than those of any of the tested bean parts.
6.2. Pathogenicity tests
The pathogenicity studies showed that the tested bean cultivars (Bronco, Contender, Giza 6 and Nebraska) varied in disease incidence. Contender bean cultivar was more resistant than other cultivars. Whereas, the more virulent Sclerotinia isolates were S5 and S6.
6.3. Histopathological invistigations
Histopathological studies were carried out in order to investigate and confirrp the modes of penetration of common bean plants with S. sclerotiorum and further histological deviations due to fungal invasion of different host tissues by u ing paraffin and electron microscope (TEM & SEM) methods.
Histology investigation of seedlings bean hypocotyls artificial inoculated with S. sclerotiorum after 24, 48, 72 and 96 hours after inoculation. Sections of samples were investigated by using either paraffin or electron microscope (SEM & TEM) methods.
6.3.1. Light microscope examinations
The penetration of bean seedlings was occurred during the first 48 hours after inoculation, through the epidermis and the outer layer of the cortex.
After 72 hours of inoculation, damage was extended deeper into the cortical cells. Infection took place inter-,and interacellularly after 96 hours more damage was occurred.
Other data
| Title | BIOLOGICAL CONTROL OF SCLEROTINIA SCLEROTIORUM, THE CAUSAL AGENT OF WHITE BASAL ROT DISEASE OF BEANS (PHASEOLUS VULGARIS L.) | Other Titles | المكافحة الحيوية لفطر إسكلروتينيا إسكلروشيورم المسبب لمرض العفن الأبيض القاعدى فى الفاصوليا | Authors | MANAR MAGDY MOHAMED NABWY KHATER | Issue Date | 2010 |
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