الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
The causal pathogen of damping-off fungal diseases of
Dodonaea viscosa and Thuja orientalis as well as those of root
rot of Acalypha wilkesiana and Hibiscus rosa-sinensis were
identified in nurseries of three governorates tested. Pathogenic
capability of the pathogens and losses in stand and plant growth
as well as several measures of control were determined.
The main findings of this study may be swnmarized as
follows:
(1) Alternaria sp., Fusarium semitectum, F. solani, Fusarium sp.
and Rhizoctonia solani were isolated at different frequencies
from roots of Dodonaea and Thuja seedlings of the three
governorates nurseries tested. Also, Botryodiplodia sp.and
Helminthosporium sp. from Dodonaea as well as Macrophomina
phaseolina from Thuja were isolated. R. solani and F. solani
showed the highest frequency in case of Dodonaea and Thuja,
while that of F. smitectum was the least.
(2) Isolation trials from Acalypha and Hibiscus root rots yielded
Alternaria sp., F. solani, Nigrospora sphaerica and R. solani at
different frequencies. While, Botryodiplodia sp. and Fusarium sp.
were only isolated from Acalypha as well as Aspergillus sp.,
Curvularia sp., F. semitectum, Mucar sp. and Pythium splendens
from Hibiscus. F. solani gave the highest mean frequency in case
of Acalypha (64.20%) and Hibiscus (34.60%), followed by R.
solani with the two shrubs tested. Also, F. semitectum and P.
splendens recorded the moderate degrees of frequencies in case
of Hibiscus.
(3) F. semitectum, F. solani, Fusarium sp. and R. solani were
found to be pathogenic fungi to Dodonaea and Thuja since they
significantly increased pre-and post-emergence damping-off than
the control (without fungus). R. solani and F. solani caused the
highest percentages of pre- and post-emergence damping-off as
well as the lowest survivals ones with the two shrubs tested.
(4) F. semitectum, F. solani and R. solani in case of Acalypha and
Hibiscus as well as Botryodiplodia sp. on Acalypha and M.
phaseolina and P. splendens on Hibiscus were pathogenic as they
significantly increased infection (%) than the control (without
fungus) in pathogenicity tests. While, Alternaria sp. and N.
sphaerica in case of Acalypha and Alternaria sp., Aspergillus sp.
Curvularia sp., Mucar sp., and N. sphaericea showed no effect
on shrubs seedling.
(5) Soaking seeds of Dodonaea and Thuja for 15 min in Topsin
M or Rizolex- T was effective measure in decreasing pre- and
post-emergence damping-off and increasing survival seedlings,
grown in soil infested with F. solani or R. solani. The fungicide
Maxim was also effective with only Dodonaea and
Vitavax/Thirum with Thuja. The bioproducts Plant Guard and
Rhizo-N, generally, gave variable effective results in this respect.
Plant Guard however, was better than Rhizo-N in case of F.
solani and the opposite result was true with R. solani. On the
other hand, Thymus vulgaris and Cymbopogon citratus were
significantly the most effective plant extracts tested in decreasing
pre- and post-emergence damping-off as well as improving
seedling survivals.
(6) Peat moss or peat moss+sand as planting media for Dodonaea
and Thuja in the presence of the soilborne fungi F. solani or R.
solani were generally effective mean in decreasing damping-off
diseases.
(7) Evaluation the efficacy of the fungicides (Rizolex- T,
Tachigaren, Tecto, Topsin-M and Vitavaxffhiram), the
bioproducts (Plant Guard and Rhizo-N), the plant extracts
(Cymbopogon proximus and Majorana hortensis) and the plant
hormones (lAA, IBA and NAA) as dip treatment for Acalypha
and Hibiscus cuttings, when planting in soil infested with F.
solani, on the disease incidence and seedling growth parameters
was as follows:
A-. All treatments tested decreased percentages of the disease
incidence than the control in all soil types. Topsin-M, however,
gave significant decreases than the control in case of Acalypha
and Hibiscus, followed by Rizolex- T with only Hibiscus. Plant
Guard, Majorana hortensis extract and IBA (Acalypha) or NAA
(Hibiscus) were the better bioproducts, plant extracts and plant
hormones, respectively.
B-. All treatments tested, except Cymbopogon proximus and IAA
in some cases with Hibiscus, significantly increased leaves
number per seedling of Acalypha and Hibiscus. Topsin-M,
Majorana hortensis and (NAA and IAA) were the best treatments
among the tested fungicides, plant extracts and plant honnones,
respectively. On the other hand, peat moss was the best soil type
in increasing leaves number/seedling.
C-. The height of Acalypha and Hibiscus seedlings was
significantly increased using all treatments tested except Rhizo-N
and Cymbopogon proximus extract in sand and clay+sand soil as
well as Majorana hortensis extract in sand soil. Rizolex- T,
Topsin-M and VitavaxlThiram were generally the best fungicides
tested in increasing seedling height. Plant Guard, Majorana
hortensis extract, NAA in case of Acalypha or IBA with
Hibiscus and clay+sand soil were superior in improving height of
seedlings than the other bioproducts, plant extract, plant
honnones and soil types tested, respectively.
D-. Topsin-M (followed by Rizolex- T in case of Hibiscus)
produced the highest number of branches Acalypha and Hibiscus
seedling and the increases than the control was always significant
Plant Guard, Majorana hortensis and rnA were superior than
Rhizo-N, Cymbopogon proximus and the other plant honnones•
respectively, in increasing number of branches per seedling. Peat
moss+sand in case of Acalypha as well as clay-sand followed by
peat moss with Hibiscus were the best soil types in increasing this
plant parameters.
E-. Roots length of Acalypha and Hibiscus seedlings was
significantly increased using all treatments tested in case of sand,
peat moss and peat moss+sand soil types. Topsin-M, Plant Guard,
Majorana hortensis and IBA (Acalypha) or lAA (Hibiscus) were
superior treatments in increasing root length among the
fungicides, bioproducts, plant extracts and plant hormones tested,
respectively. On the other hand, peat moss+sand (Acalypha) and
peat moss (Hibiscus) were the best soil types in improving root
length.
F_. Root weight/seedling was increased by each one of the
treatments tested than the control (without treatment). Topsin-M
and Vitavax/Thiram (Acalypha) as well as Topsin-M followed by
Rizolex-T in case of Hibiscus were generally the best fungicides
in improving root weight/seedling. Also, Plant Guard, Majorana
hortensis extract and IAA in case of Acalypha as well as NAA
with Hibiscus were the best treatments among the bioproducts,
plant extracts and plant hormones tested. On the other hand,
clay+sand and sandy soil were superior soil types in increasing
root weight/seedling in case of Acalypha and Hibiscus,
respectively.
G-. All treatments tested significantly improved seedling weight
than the control in case of both Acalypha and Hibiscus shrubs.
Topsin-M followed by Rizolex-T, Plant Guard, Majorana
hortensis extract, IBA and clay+sand were found to be the best
fungicides, bioproducts, plant extracts, plant hormones and soil
types in increasing seedling weight. In contrast, the fungicide
Tecto, the hormone IAA and sandy soil were the least effective
treatments in this respect.
(8) Effects of dip Acalypha cuttings in each one of 5 fungicides,
2 bioproducts, 2 plant extracts and 3 plant hormones on disease
severity as well as root number and length of seedlings growen
for 10, 17 and 24 after planting in natural or sterilized soil
uninfested or infested with F. solani are as follows:
A. Sterilized soil (sand+clay), uninfested or infested with F.
sol ani:
Topsin-M completely prevented the fungal infection and greately
improved root number and length/seedling in all periods tested,
followed by Vitavax/Thirarn and Rizolex-T. Rhizo-N, Majorana
hortensis extract, all hormones tested were found to be of great
importance in decreasing disease severity and in improving roots
number and length/seedling. rnA, however, was the best
hormone in this respect.
B. Natural soil (sand+clay), uninfested or infested with F.
solani:
Topsin-M significantly increased roots number and
length/seedling and completely prevented fungal infection during
the three periods tested, followed by Vitavax!fhirarn in most
case. Rhizo-N, Majorana hortensis extract and IBA were,
however, superior than the other bioproduct, plant extract and
plant hormones tested in decreasing disease severity and in
improving root growth parameters. In this respect, all plant
hormones tested increased significantly root length and numbers
per seedling as well as decreased disease severity than the
control.
(9) The efficiency of some fungicides (Rizolex-T, Tachigaren,
Tecto, Topsin M and Vitavax/Thiram), bioproducts (Plant Guard
and Rhizo-N), plant extracts (Cymbopogon proximus and
Majorana hortensisy and plant hormones (IAA, IBA and NAA)
as dip treatment for Acalypha cuttings on total sugar and phenol
contents in seedling roots, grown in sterilized and unsterilized
(normal) sand+clay soil infested with F. solani was as follows:
A. Total sugar contents in roots of Acalypha seedlings grown in
sterilized soil (without infestation) were equal in value with all
treatments tested and the control. While, they always decreased
than the control in roots of seedlings grown in sterilized or
unsterilized soil infested with F. solani and in unsterilized soil
without artificially infestation. Among the fungicides and the
other treatments tested, Topsin-M, VitavaxfThiram and Rizolex- T
gave the lowest amount of the total sugar contents in seedling
roots, while the opposite result was found with the fungicides
Tachigaren and Tecto. Plant Guard decreased sugar contents
more than Rhizo-N of sterilized soil, while the reverse was
occurred in case of unsterilized, uninfested or infested with F.
solani. Also, Majorana hortensis extract and NAA were effective
treatments than Cymbopogon proximus and the other hormones,
respectively, in most cases.
B. Total phenol contents in roots of Acalypha seedlings grown in
sterilized soil (without infestation) were equal in value with all
treatments tested and the control. While, they always increased
than the control in roots of seedlings grown in sterilized or
unsterilized soil infested with F. solani. The highest phenol
contents were found in case of Topsin M, Rizolex-T and
Vitavaxffhiram, followed by the bioproducts (Plant Guard and
Rhizo-N), Majorana hortensis extract and IBA plant hormone in
sterilized, infested soil and unsterilized, uninfested or soil
infested with F. solani.