Susceptibility of Different Date Palm Cultivars to Infection By Terminal Bud Rot Caused By Thielaviopsis paradoxa (Deseyn) Hohn.
Basrah Journal For Date Palm Research,
Volume 5, Issue 1, Pages 29-41
AbstractThis study was carried out in laboratories of plant protection department,
Agriculture College. to evaluate susceptibilty of different cultivars of Date palm
(produced by seed and tissue culture) to infection by terminal bud rot disease
caused by Thielaviopsis paradoxa.
The results of survey of terminal bud rot disease in different locations in
Basrah province showed that the highest percentage of infection was recorded in
orchards of shatt-Al-Arab which reached 33.51% followed by Al-Qarna and
Abu Al-Khasseb. While the lowest percentage of infection was recorded in Al-
Medina reached (4.54%).
The results also showed that was a positive correlation between the
infection rate and the salinity, alkaloids of soil.
It was found that the cultivars of date palm (Hilawii, Sayer, Breim and
Zahdi) were the most susceptible to infection by T.paradoxa. The percentage of
infection was (36.66, 34.8, 30.9 and 29.11%) respectively.
The study proved the significant differences between callus treated with
cultural filtrate of T.paradoxa and untreated callus. Weight of callus decreased
as the concentration of fungus culture filtrate increased, callus weight was
(0.382gm) at concentration of 20% which then decreased significantly to
(0.274gm) when the concentration was 30% growth completely failed at 50 and
It was also found that all seedling of different cultivars of date palm
produce by seed was susceptible to artificial infection of T.paradoxa. symptoms
appeared on seedling as yellowing, wilting and brewing on crown area-However
the most decreases in fresh and dry weight was found in seedling of Hilawii,
Sayer, Breim and Zahdi while the lowest decrease was in Berhi seedling. Many
fungi like Fusarium spp was isolated from shoot and root system of date palm
and from larva of shoot Pseudophilus testaceus but T.paradoxa was not isolated
from larva of P.testaceus.
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