الفهرس 
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Abstract
Tomato powdery mildew disease is considered one of the
most important diseases, which attack tomato Nile plantations in
Egypt causing great damage to foliage and yield. The results of
the present pathological, physiological, and control studies can
be summarized as follows :-
1. Tomato powdery mildew disease was more severe in both
Ismailia and El-Fayoum governorates than in middle and
governorates of Upper Egypt (Giza, Beni . Suer, EL Minia and
Sohag). Whilst the least disease severity was found in El-
Minufiya and Qalubiya governorates.
2. Disease severity increased progressively from June until
September, then begin to decrease to reaches its minimum
value during November. The infection and development of
tomato powdery mildew disease seemed he correlated with
the prevailed averages of both temperature and the relative
humidity.
3. According to the observed disease symptoms and
characteristics of the conidial stage, the causal fungus
identified as Leveillula taurica.
4. Investigations revealed the absence of the perfect stage of
L. taurica (Lev -) Arnaud under greenhouse and field
conditions.
5. The artificial inoculation to different hosts under
greenhouse conditions revealed that tomato, eggplant and
artichoke were the most susceptible hosts to infection with L.
taurica followed by pepper and common bramble. However,
Egyptian mallow, hollyhock, roselle, kenaf and nasturtum
were the least susceptible hosts.
6. Powdery mildew could infect all tested tomato cultivars
but to different extents. Supermarmande, Strain- B, Marconi
and Super green were highly infected cultivars, meanwhille.
Peto-86 and Castle rock were moderately infected. On the
other hand, DC 97/3, Cal-Ace, Ace and Super strain-B were
the least infected cultivars.
7. Different plant genera i.e. tomato, pepper, eggplant,
common braMble, artichoke and hollyhock were inoculated
individually with six isolates of L. taurica obtained from
these genera. The obtained results revealed that each isolate
was more severe, in most cases, on its specific host than the
other rested hosts. However, conidia of the fungal isolates
introduced from eggplant and common bramble could not
infect pepper and artichoke, respectively.
8. Percentage of conidial germination was higher on tomato
epidermal strips than on dry slides or in water.
9. Clove oil, clove water-extract and garlic water extract
were more effective for suppressing conidia germination than
the other tested materials. Contrariwise, nigella oil. Rue
water extract, manufactured misrona oil, henna and ginger
water extracts, manufactured Natrlo oil, Triology (neem oil),
thyme and eucalyptus: water extracts. mustard. onion,
caraway, fennel and. jojoba oils encourage conidial
germination compared with check water treatment.
.SiIilunaY),
10. Spraying tomato plants grown under green house
condition with different concentrations of the above
mentioned materials one day before artificial inoculation with
conidia of Leveillula taurica revealed efficiency of Clove
oil, Clove water extract, Garlic water extract and Nigella oil
in suppressing powdery mildew disease intensity when used
at 0.8%, 0.1%, 5.0% and 25.0%, respectively. Aprilying the
latter 4 materials at concentration mare than 0:8cilo, 25.0%,
50.0% and 25.0%, respectively resulted on phytotoxlic effects
on treated plants.
11. Degree of L. taurica infection seemed to correlate with
number of stomata and hairs on tomato leaves. The least
susceptible cultivars UC-9713, Cal-Ace, Ace and Super
strain- B possessed the fewer numbers of stomata and the
higher numbers of hairs especially glandular hairs compared
with the highly susceptible cultivars Supermannande, Strain-
B, Marconi and Super green.
12. Artificial infection with tomato powdery mildew [1.
taurica] resulted in noticeable decrease in chlorophyll (a),
chlorophyll (b) and carotene pigments in diseased tissues.
The’ highest disease severity found to be associated with the
greatest reduction in these pigments.
13. Sugars content including reducing, non reducing and total
sugars contents were obviously higher in healthy leaves of
the highly susceptible tomito cultivars Supermannande and
Strain-B compared with -th, less susceptible Ace and Super
strain-B tomato cvs. In boib groups of tomato cvs., sugars
content was decreased in tomato leaves infected with 1.
taurica. The highly susceptible cultivars showed higher
reduction due to infection than the least susceptible cultivars.
14. The healthy leaves of the least susceptible to mato cvs.
Super strain-B and Ace found to be contained higher
quantities of free phenolic compoppds than i t4 highest
susceptible cvs., Supermarmande and Strain-B. Arhounts of
phenol compounds particularly free and total phenols were
increased in diseased leaves compared with the healthy ones.
The highest increases of phenolic compounds were
associated with the least susceptible cultivars.
15. The highly susceptible tomato cvs. contained higher
contents of free amino acids than the least susceptible ones.
In all tested tomatoes the free amino acid content decreased
considerably in diseased leaves compared with the healthy
ones. The least susceptible cultivars contained higher
concentrations of sulphoric and aromatic amino acids and
lower concentrations of the hydroxylic, alephatic and Emeno
(especially proline) amino acids than the high susceptible
cultivars. In healthy leaves the aromatic amino acid
tryptophan was higher in the least susceptible cvs than the
high susceptible cvs but it was sharply decreased after
infection in all cvs.
16. The least susceptible tomato cultivars contained higher
concentration of vitamin c (Ascorbic acid) than the highest
susceptible ones. Reduction in quantities of vitamin c due to
powdery mildew infection was higher in the least than the
highest susceptible cultivars.
Summary ’132
Summary 133
17. Powdery mildew infection increased the rate of
activity/sec. of all oxidative enzymes (peroxidase,
polyphenoloxidase, catalase and ascorbic acid oxidase)
compared with check plants. Clear correlation was detected
between each of rate of activity/sec. of each enzyme and
relative susceptibility of the three tested tomato cultivars. The
less susceptibility of the cultivar, the more rate of
activity/sec. was resulted.
18. In healthy leaves, levels of the growth promoters [IAA,
GA3 :& cytokinins] and growth inhibitor [abscisic acid] were
higher in the high susceptible cultivar, Strain-B than the
moderately (Castle rock) and the least (Super strain-B)
susceptible cultivars. In most cases, growth promoters were
higher in mildewed than healthy leaves of all tested cultivars.
However, the infected leaves of the least susceptible cultivar
contained the highest increase in total amounts or growth
regulators followed by those of the moderate and the highly
susceptible cultivars, respectively compared with their
healthy leaves.
19. As for effect of fungicides on L. taurica spore
germination. the present results proved that the fungicide
delmite only could nearly prevent L. taurica conidial
germination, whilst microthiol-80, flint, thiophate-14 and
domark were significantly less effective.
20. Under greenhouse conditions, all tested fungicides used
one day before inoculation caused significant reduction in the
disease severity compared with control treatments. In this
respect, the fungicides topas-200. domark and bayfidan were
the best followed significantly by rubigan and sumi-8.
However. the fungicides golf. inicrothio 1-80, delmite and
thiophate-14 were less effective.
21. Under field conditions, the systemic fungicides Topas- 200
and Domark were the best for reducing powdery mildew
severity and increasing the yield/feddan followed by the
systemic ”bayfidan followed by delmite. inicrothio 1-80 and
thiophate-14.