الفهرس 
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Abstract
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Seed of some vegetables belong to family Cucurbitaceae
(cucumber, squash and cantalope) and other belong to tamely
Solanaceae (pepper and tomato) used under protective agriculture
system (greenhouse and tunnel) were tested to the presense of
associated fungi, bacteria and viruses.
Isolation trials yielded 43 fungi including in 11 genera.
•
Genus Fusarium was dominant on all tested seeds. Results of
survay using blotter method show that tomato var. Dombo and
Dombito~ pepper var. Gedion; cucumber var. Danimas and
Maram; squash var. Eskandrani and canta1~ var. Dokki gave
highly percentages of germination and less infection percentage
than other tested varieties. Generally, the disinfected seeds gave
higher percentage than non disinfected ones. Contrary to the
germination results, the infection percentages were higher with
non-disinfected than disinfected ones.
While using agar plate medium, cucumber var cordito and
Maram and pepper var no 1920 gave highly percentage of
gennination, in the some time no fungi associated with them.
On the other hand using sand method clear that cucumber
var. Danimas and tomato var. Vacholta associated only with fungi
present on outer surface of seeds.
SU11U1UlTf/ 881
The comparison between the three methods of isolation
showed that agar plate technique gave higher results of
germination and percentage of infection and subsequently the
presence of associated fungi than the two other methods.
Alternaria tenuis and Fusarium solani were the most
effective fungi on increasing the infection. Percentage of cucumber
and squash plants and subsequently, the healthy survival plants
which were low. Alternaria tenuis and Fusarium moniliforme
were the most effective isolates on infection percentage of tomato.
All the tested fungi has great •effect on reducing the healthy
survival plants compairing with control plants.
The greatest effect of filtrates was Rhizoctonia solani filtrate
which gave the lowest seed germination percentages in case of
cucumber and squash, While Alternaria tenuis caused the lowest
ones in case of tomato. The effect offiltrates was depend also on
plant variety i.e. the effect of filtrates was more pronounced on
cucumber seeds followed by squash and then tomato seeds.
The effect of some fungicides in different concentrations
proved that Benlate greatly affected growth rates of Rhizoctonia
solani, Fusarium oxysporum and F moniliforme. Rhizolex
affected growth rates of Rhizoctonia solani and Alternaria tenuis.
Gallin/mancozieb was less affected fungicide according to others.
Generally, these results showed that, the more affected fungi under
these conditions were Rhizoctonia solani and Alternaria tenuis
and more effective fungicides were Benlate followed by
VitavaxlTiram then Rhizolex
summary 89
Ninteen isolates of bacteria were isolated from seed samples,
These bacteria were two groups, First group was pigments
producers and pathogenic to plants which isolated from their
seeds, Second group was non-pigmentation producers and caused
rots to the seeds.
Thirteen of isolated bacteria were rod shape and one isolate
was long rod shape.
Dipping of the cucurbits seeds in suspension of isolated
bacteria and grown in pots, Two isolates caused typical bacterial
symptoms which affect leaf margin and cause dark green color
lesions of cotyledons.
Plant inoculation with all isolates produced flouresent
pigments caused bacterial disease symptoms, On the basis of
morphological and physiological properties, and pathogenictity
test. Two isolates were P. syringae pv. Lachrymans and other
green-fluorscent pseudomonads are considered unknown
saprophytes.
Samples of squash plants showing viral symptoms and
growing under tunnels were indexed on healthy squash plants and
developed systemic viral symptoms after 10-15 days from
inoculation. The symptoms were classified into three groups.
First group was those isolates showing systemic symptoms, vein
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third group was those showing filiform shape, Vein-banding,
blisterS, cup shape and death. The percentages of infection
obtained were 10,90 and 90 in pots and 50,66 and 80% in plastic
tunnel for isolates 1, 2 and 3, respectively, indicating that they
were different in their infectivity.
The three isolates did not prodUcedeltternal symptoms on
the inoculated squash cotyledons, while systemic infection was
developed on the true foliage leaves of these plants.
Three host plants belong to family cucurbitace
ae
were
susceptible to infection with the three virus isolates. Squash
viruses which obtained from diseased squash leaves and bad
positive reaction on tested plants of cucurbits, gave negative
reaction with the other 13 host plant.
They also gave chlorotic local lesions on Chenopodium
amaranticolor. These symptoms indicating that they may be
watermelon mosaic virus (WMN).
The three viruS isolates were mechanically transmitted by
aphids (MyzUS persica and AphiS gossypii) in non persistent
manner.
seed transmission trials failed to transmit the virus through
squash seeds.
The inclusions bodies of isolate 1 and 2 were crystalline
shape, while for isolate 3 were spindle shape.
Flelt
uOUS
filaments particles were showed by electron
microsCOpewhich from infected squash plants.
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Summa? 91
On the basis of symptomatology, host range, mode of
transmission, inclusion bodies and electron microscope. The virus
may be is watermelon mosaic virus-2 (WMV-2).
A highly reduction in plant height, fresh and dry weights of
whole plant and chlorophyll content of plants infected with each of
the three isolates was obsereved.
Isolate 1 affect growth parameters greatly than the other 2
isolates.
The number of flowers ot infected plant with isolate 1 was
lower than control, wile flowers of plants infected with isolates 2
and 3 were almost the same or slightly higher. The number of
fruits, percentage of fruit setting, showed a great reduction than
control. Flowers of plants infected with isolate 1 failed to continue
for fruit setting and subsequently the yield.
Infected cucumber plants grown under plastic-house
developed systemic viral symptoms, as sever mosaic, blisters and
filiforme after 15-25 days from inoculation.
The three virus isolates developed systemic infection
symptoms on the true leaves of cucumber plants. These symptoms
were observed as severe mosaic, blisters and filiforme shape after
15-25 days from inoculation.
Thirteen host plants belong to 11 speciies and 4 familes were
tested to virus infection. Out of them, ten host plant were
susceptible to infection with the virus isolates 2 and 3. They
showed the characteristic virus symptoms, while 3 host plant
SuttU1Ul1Y 92
belong to one family (Leguminosae) were not susceptible to virus
infection. Symptoms were mosaic, yellow systemic on Cucurbita
pepo, systemic mosaic and stunting on cucumber and watermelon,
systemic mosaic and filiform shape on Nicotiana tabacum. N.
glutinosa, Lycopersicon esculentum, Capsicum annuum and
Datura stramonium for isolates 1 and 2. No symptoms were
obsereved on Phaseolus vulgars, Pisum sauvum and Viciafaba.
from host range results these symptoms were typically cucumber
mosic virus (CMV) for isolates 1 and 2. •
The three virus isolates were transmitted mechanically and
easly by aphids (Myzus persicae and Aphis gossypii) In nonpersistent
manner.
Seed-transmission trials failed to transmit the virus through
cucumber seeds. In all cases, the plants can’t complete his life
cycle and develope seeds.
On the basis of symptoms, host range, mode of transmission,
inclusion bodies and electron microscope. The virus may be is
cucumber mosaic virus (CMV).
Plant height, fresh and dry weight of infected plants were
greatly lower than healthy plants. Chlorophyll contents of healthy
leaves was higher than infected ones.
Cucumber plants infected with isolates 1 and 2 failed to
produce fruits, while isolate 3 affect the fruit setting and
subsequently the yield. Average weight of cucumber fruit of