BACTERIAL BLIGHT OF CASSAVA (Manihot esculenta Crantz) IN THE DRIER SAVANNAS Of NIGERIA
BACTERIAL BLIGHT OF CASSAVA (Manihot esculenta Crantz) IN THE DRIER SAVANNAS Of NIGERIA
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Date
1995-08
Authors
DUALA, SAMUEL TABOT
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Abstract
Cassava bacterial blight is the most important of several
bacterial diseases of cassava and is of wide occurrence in Nigeria.
Surveys were undertaken at Zaria and other sites in the
Northern Guinea and Southern Guinea Savanna zones to evaluate the
incidence and severity of the disease. The incidence and severity
of the disease were higher in the Southern Guinea Savanna zone than
in the Northern Guinea Savanna zone. Some variations were observed
within every environ visited and these were attributed to the
nature of crop mixture, cassava cultivar type, spacing and plant
age.
The incidence and severity of the disease were significantly
reduced following late planting with a local cassava variety while
the decrease was non-significant with the improved variety TMS
4(2)1425. in the intercrops, a significant reduction of the
incidence and severity of the disease were achieved with the
improved variety. On the other hand, incidence and severity of the
disease were significantly higher in the sole improved cassava.
There were no significant differences between the time of
introduction of the components of the mixture on the incidence and
severity of the disease in both varieties.
Screening for resistance to the disease in field and in pot
trials using six cassava varieties revealed that disease incidence
and severity were lowest in TMS 30572 and TMS 1(2)1425 while a
local variety, TMS 91934 and 60506 were highly susceptible.
The improved cassava varieties TME II, TMS 305" TMS 4(2)1425, TMS
81983 and the local varieties, Isu and Broni were identified as
being fairly resistant to bacterial blight compared to other
varieties tested in two different trials.
Leaf trash collected in the field from beneath diseased plants
at approximately 9 months yielded the pathogen. In both local and
improved cassava varieties, bacterial populations in the trash were
found to be minimum in April and maximum in October.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY, ZARIA, IN PARTIAL
FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE
OF MASTER OF SCIENCE IN CROP PROTECTION.
DEPARTMENT OF CROP PROTECTION,
FACULTY OF AGRICULTURE,
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA.
AUGUST, 1995
Keywords
BACTERIAL,, BLIGHT,, CASSAVA,, (Manihot esculenta Crantz),, DRIER SAVANNAS,, NIGERIA