BACTERIAL SOFT ROT OF TUBERS INDUCED BY ERWINIA SPP. (JONES)
BACTERIAL SOFT ROT OF TUBERS INDUCED BY ERWINIA SPP. (JONES)
No Thumbnail Available
Date
2006-04
Authors
SIMEON, AMODU UMORU
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The incidence of bacterial soft rot was investigated in three markets in Zaria area namely:
Samaru, Wusasa and Sabon Gari markets. Examination of symptoms on tubers (both
wounded and unwounded), were done on tubers stored under different environmental
conditions in order to determine the factor(s) that might predispose them to attack by the
soft rot pathogen. High populations of Erwinia spp. were isolated from the samples
collected from various markets, which was an indication of high inoculum level from the
various soils of origin or storehouses. Tubers without symptoms were frequently
contaminated, usually at eye, lenticels and heel end, suggesting contamination from
mother tuber to progeny. Aqueous extracts of neem (Azadirachta indica A. Juss),
Eucalyptus leaves (Eucalyptus citrodorus (L)), Lemon grass (Cymbopogon citratus
(stapf)), Garlic bulb (Allium Sativum (Linn)), Ginger (Zingiber officinale) (Roscoe)) and
Aloe vera were evaluated for the management of bacterial soft rot. Two methods were
used, namely in vitro methods and on the tubers both whole and sliced. Lemon grass had
the greatest inhibitory effect and it’s statistically comparable with garlic, Aloe vera, borax
and neem extracts. Eucalyptus had the least inhibitory effect and statistically similar to
ginger extract. Two methods (Tuber slice assay and point titration assay) were used to
screen yam (Dioscorea rotundata), sweet potato (Ipomoea batatas), Irish potato
(Solanum tuberosum), cocoyam (Xanthosoma sagittifolium), cassava (Manihot esculenta)
and carrot (Daucus carota) for susceptibility to soft rot bacteria. Irish potato ranked the
most susceptible followed by carrot, sweet potato, yam, cocoyam and cassava. The two
methods examined were considered to be effective for screening tubers for bacterial soft
rot. However, with the single site titration assay, it is possible to determine not only the
extent of tissue maceration but also the bacterial population necessary for initiation of
lesions. Tuber Slice assay on the other hand, has the advantage of being faster than the
single site titration assay.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY, ZARIA
IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE DEGREE OF
MASTER OF SCIENCE IN CROP PROTECTION
DEPARTMENT OF CROP PROTECTION
FACULTY OF AGRICULTURE
AHMADU BELLO UNIVERSITY
ZARIA, NIGERIA
APRIL 2006
Keywords
BACTERIAL,, SOFT,, ROT,, TUBERS,, INDUCED,, ERWINIA,, SPP,, JONES,