الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
SUMMARY
T te present investigation was planned to study the causals of leaf
spots diseases of grapevine plants and effect of some physiological and
biolog.cal factors govering the outbreak and control the diseases caused
by ’Drechslera tetrameta (Mckinney) Subram and Jain (J{e{mintfwsponum
tettamera) Mckinney, Derchslera rostrata (Drechs.) Richardson and Fraser
(:J{e{mil~tfwsporium rostratum} Drechs. and 5ffternaria ahernata (Fr.) Keissl. on
grapevine plants. The findings can be summarized as follows:
1. Tae fungi isolated from spotted grapevine leaves were Drechslera
tetramera, Drechslera rostrate and %ternaria a£ternata.
2. Pathogenicity studies revealed that all isolated fungi were pathogenic
tc both grapevine cultivars and V. tetramera followed by ’D. rostrate
cursed the highest disease index under laboratory conditions. Also,
results exhibited that Banaty (Thompson seedless cv .) more
st.sceptible to infection with the tested fungi more than Bez El-Anza
(seeded cv.).
3. P:)A and Czapek’s media were the best ones for both the rate and
weight of growths of all the tested fungi, while pepton-Dextrose agar
medium was the lowest one in this respect.
4. Sodium nitrate, Asparagine were the best nitrogen sources for linear
and weight of growths for all the tested fungi. Whereas, Ammonium
cl iloride shows the least growth for all of them.
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5. Growth of ’D. tettamera, ’D. tostnua and J’l.. aitenuua was better on
glocose and sucrose as a sole source of carbon. Whereas, starch gave
the lowest growth for all of them.
6. ’1). tctramera and ’D. rostrate grow well under darkness followed by
yelle w light wave length. Whereas, 51. aitemata grow well under
darkness followed by blue light wave length.
7. The linear and weight of growth of all the tested fungi i.e.
’D. tetramera; ’D. rostrata and 51.. altemata were affected by different
temp~ratures. They were increased as the temperature increased till
25°C then decreased. It was also, clear that there was a clear DROP in
the 1near and weight of growth above 30°C. Also, the growth of
Yr. altcrruua affected by increasing temperature above 30°C more than
’1). tet ramera and ’D. rostrate.
8. Topsii M 70 was the most effective fungicide and checked both
linear and weight of growth of all tested fungi at the concentration of
400 ppm followed by Bayleton 25 and Coprafit 50.
Bath spore germination and genn-tube-Iengths were completely
checked at concentration of 200 ppm Topsin-m-70 for all tested
fungi. Whereas, Bayleton 25 and Coprafit 50 reduced spore
gerrnir ation and tube-lengths of all tested fungi till the concentration
400 ppm,
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9. All filtrates of the different isolated fungi affected to great extent on
the appearance of wilt in tomato cuttings and maize seedlings. The
effect of V. tetramera filtrate was resemble to that of V. rostrata
whic 1 the wilt was appeared after 48 hrs. for tomato cuttings and
after 72 hrs. for maize seedlings. Whereas in case of ~. aiternata the
wilt was apeared after 60 and 72 hrs for tomato cuttings and maize
seedl:ngs respectively. Also, the effect of filtrate on the appearance
of wi t differed with the difference in the concentration of filtrate.
10. Treati ng seeds of tomato and grains of maize with different filtrates
of the tested fungi reduced their percentage of germination. In this
respect the fungal filtrates of ’1). tetramera and ’1). rostrata were the
most effective than filtrate of Jf.. alternaia.
11. All the different tested fungi could decompose and utilize purified
pectin as a single source of carbon. However, ’D. tetramera gave the
best linear growth on both normal and pectin media followed
by ’D. »strata.
12. All fungi have the ability to secrete PG enzyme more than PME.
Howev er, ’1). tetramera secrete PG enzyme more than ’D. rostrata and
~. after. uua: Also, the ability of v. tetramera to secrete PME enzyme
exceeds that of 51.ahenuua and V. rostnua.
13. All fun ~i exihibited the ability to decompose starch and secrete
amylase enzyme. Amylase activity of Jl. altemata exceeds that of
V. tetranera and v. rostrasa, On the other hand, the activity of
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’lJ. ros ’rata exceeds that of ’D. tetramera after three and six days from
incuba tion while after 9 days the apposite was recorded.
14. The fi: ngi t£J. tetramera and ’D. rostrata were more active in Gelatin
liquefa ction than 51. aitenuua especially after 9 days from incubation.
15. All the different tested fungi showed slight activity of PG, PME and
Cx enzymes. However, activities of Cx enzyme were more
conspicuous than PME and PG enzymes. Also t£J. rostrata was the
most a ctive in secreting all enzymes, PME, PG and Cx than
’lJ. tetnimera and Jl. altemata:
16. In vitro, both PG and Cx enzymes were most active at a wide range
of pH values (5.5 to 7) especially those of V. tetramera and V. rostrata.
HoWeVtT,the maximum activity for ’D. tetramera was at pH 5.5 with
time of inoculation 21 days.
The relative activity of fungal PG and Cx enzymes increased
with the increase in time of reaction as well as the increase in culture
age. Jl. .titernata showed the lower activities of both enzymes in its
culture filtrates at 14 and 21 days of culture ages. Also. the
correlation between pectinolytic and cellulolytic enzyme activity and
virulence of fungus could be noticed in case of V. tetramera which
was mon ~virulent than both V. rostrata and 51. alternata.
17. Topsin M: 70 was the most effective fungicides as it cheked Cx
activities of 30 ppm after 15 min. for all the tested fungi. Bayleton
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-- _ .. _-- - --- - -- ---- - - _. --- - -- -- -- ---_._-
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25 ar d Coprafit 50 ranked the second in this respect. Topsin 70 was
more effective on ex activity of V. tetramera and v. roserasa than that
of 52l. uitemaria.
18. Both pectinolytic and cellulolytic enzymes were detected in each of
healthy and infected grapevine leaves. Healthy Bez EI-Anza
grape, .ine leaves showed the highest activities than leaves of Banaty
cultivar,
19. In vitro, the tested fungi differed in their polyphenol and peroxidase
activity. As for polyphenol oxidase enzyme, 52l. afternaria was the
most ;ictive fungus at the three different duration times of
inocula tion, whereas, V. tetramera was the most active fungus in their
activity with peroxidase enzyme. Both polyphenol and peroxidase
were ckarly decreased with increasing the old of culture filtrates for
all the t ested fungi.
20. In vivo, the healthy leaves of the resistant Bez EI-Anza cv. showed
high pol yphenol and peroxidase activity than the susceptible Banaty
cv. Peroxidase and polyphenol oxidase activity generally increased
in infect~d leaves of both cvs., after 6 and 9 days from inoculation
then dec:’eased with time.
21. In vitro, nocularion with the different tested fungi caused decreases
in the illy weight of leaves for the two cultivars. Also, the dry
weight of leaves decreased with increasing of lnoculanon periods.
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22. In uioo, foliage-spraying with fungicides. nutrient sOlutions and their
combi lations lead to an increase in the leaves dry weight for the two
cultivars compared with untreated leaves. Also, results in this
respect show that the foliage-spraying with fungicides and nutrient
sotunoa in combination could be playa role in increasing leaves dry
weight.
23. Both reducing and total sugars percentages increased greatly after
infection with leaf spot diseases. On the other hand, spraying with
fungicides, nutrient solutions and their combination in the most of
treatmen ts showed a decrease in redUcing and total sugars in Banaty
cv. While the contrast was found in case of Bez EI-Anza cv.
24. Free and total phenols were Produced and accumulated at a faster
rate in Bez El-Anza (resistant cv.) than that of Banaty cv. As regards
the conju gated phenols, an apposite trend in both tested cvs. was
noticed. ;>praying with fungicides or nutrient solution or their
combinati)fl was Dot effective in increasing the free and total
phenols compared with healthy leaves’ while the contrast was
noticed in case of diseased leaves.
25. Total free amino acids were higher in diseased leaves than the
healthy ones. Also, the resistant cv. Bez EI-Anza contained higher
levels from total fre amino acids than the susceptible cv. Banaty. As
regards, the effect of spraying with fungicides or nutrient solutions
and their combination Was differed with the difference in the
treatments. ;praying with Coprafit 50 + Feterlion, Copranr 50 +
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Foliar and Topsin 70 detected an increase in the total free amino
acids in Banaty cv. While spraying with Feterlion~ Feral, Bayleton
25 + Foliar and Topsin 70 + Foliar exhibited an increase in bez
El-Anza cv.
26. Under field conditions generally, spraying with fungicides, nutrient
solution) and their combinations were effective in decreasing disease
index. However, spraying with Topsin 70, Bayleton 25 + Feral,
Coprafit 50 + Foliar, Topsin 70 + Feral and Topsin 70 + Foliar
showed ~e lowest percentages of disease index in caes of Banary
(suscepti ole cv.). Consequently the best yield was obtained with
them. Wrile in case of Bez E1-Anza (resistant cv.) spraying with
Bayleton 25 + Feral, Topsin 70 + Foliar, Bayleton 25, Topsin 70 +
Feterlion and Topsin-m-70 + Feral showed the lowest percentages of
disease index and nearly most of them gave the highest yield. Thus,
foliage-sp raying with fungicides and nutrient solutions ill
combinati,m could be playa role in decreasing the percentages of
disease index and increasing the yield.