Etiology and control of stem rot of sunflower (helianthus animus l.)
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Date
1988
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University Of Agriculture
Abstract
Surveys were curried out on the distribution in Tanzania of a
new sunflower disease first observed in Morogoro Region.
Experiments
were conducted at the Tropical Pesticides Research Institute (T.P.R.I.)
ana Sokoine University of Agriculture (SUA) to identify the causal
agents, assess their pathogenicity to sunflower varieties commonly
grown in Tanzania and other crops normally grown in association with
sunt lower, and to determine biological activity of some selected
fungicides to the disease causing organisms.
Out of all eight surveyed
regions, sunflower stem rot was confirmed only in Morogoro region.
Fusarium moni liforme She Id and F. graminearum Schwabe were identified
as the causal organisms inciting the new sunflower disease which was
later named "sunflower stem rot".
Sunflower- varieties namely Record, Jupiter, Gor 104 and Dwarf
comet were found less affected by both Fusarium spp. while Giant
549,
IS 894,
IS 894 amd 6F5 were more susceptible.
Groundnuts, simsim.
cowpeas and greengram did not show symptoms upon artificial inoculations
with the two Fusarium spp. while maize, sorghum, beans and garden
peas showed necrotic symptoms in the areas inoculated.
The fungicides Sisthane (fenapanil) and Ridomil (metalaxyl) were
not effective against both fungi in laboratory culture tests while
Benlate (benomyl) was effective.
But Benlate proved inffective in
controlling the disease in the field during field tests.iv
Severity of sunflower stem rot was more apparent in fields planted
a t ve ry
close spacing whether it was a monoculture or interplanted
with other crops resulting in more plant deaths.
It is recommended that sunflower varieties which were found resistant
be distributed to peasants in Morogoro Region and that only resistant
ij Ten r. .1 be used in
crops like groundnuts, simsim, cowpeas
intercrop u- f
lower and all other
Wherever stem rot is endt
intercrops should be planted at w’^nr tpacin
which favour disease development.
. *“het
particularly on breeding for more
■e •’void overcrowding
”C se.i <_«> is being suggested
t« nt van
The suitability of fungicide «_or.- : -I cf
.> s.
in peasant
grown sunflower appears remote an<" .‘:urrLe«r ;.r /e i.^vxuns on
this aspect sl.nould be on large farms
Description
Keywords
Sunflower plant, Etiology, Helianthus annuus L, New sunflower disease