الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
-SU-M..•M_A-R-Y~
Pruit rot diseases are the most serious diseases that
attacking strawberries in ARE, causing considerable losses
in guantity and quality of 7ield.
The present investigation was planned to study : a)
The causals of fruit rot diseases. b) SCDe physiological and.
pathological studies on Ph.ytophthora cactorum. c) Enzyme
activities in both culture filtrates and in un-inoculated
and inoculated fruits with l.cactorum. d) Chemical constituents
of un-inoculated and inoculated fruits with -P. eactorwn. e) Host range of Z•.C•,;.;8•C•••t•..O••r••.um,;a;n;d strawberry cuIt1vars
. resistance. f) Bftect of some 1’uDg1.cides oil l.cactopn
in laboratory and leather rot disease in greenhouse •.
Results obtained can be summarized as follows :
1) Four fungi namely; PNtophthora cactorum (Leb. &: Cohn.)
Schroet, Botptis cinerea Fers. ex-Fr., Rhizoctonia
( Cort:l.c1um) solam (Prill & Delacr) Bourd& Gals and
RhizopuB nigricans (Ehrn. ex-Fr.) Lind. were isolated fran
infected fruits of four straWberry cnltivars collected from
different governorates in BgJpt;However, l-caetorum was
isolated for the first time in Egypt and it was isolated
also more frequently than the other fungi.
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2) Pathoginicity teats in laboratory revealed that all
the tested fungi were found to be pathogenic to strawbe~
frui ts with different degrees. However, l.cactorum was the
most virulent fungus in both pre-mature
and mature (wounded and un-wounded) cr strawberry
fruits.
3) Results of PhysiologiCal and pathologiCal studies on
~.cactorum could be summarized as follows :
a) CDA mediumwas the best media for mycelial growth and
number of sporangia, anther1dia and oogonia. Whereas, v-a
jUice mediumwas the best one for Oosporea production.
b) The optimum temperature for fungal growth was found, to
be 25°0. minimumand max1mum temperatures were 5 0c and
35°C respectively. In this respect, sexual reproduction
was favoured by low temperatures on contrast with ase%Ual
reproduction •
C) Glycerol, galactose, ratinose and dextrose did not
permit any growth of E,.cactorum when each was used as the
sole carbon source in the medium. Similarly, sodium nitrate
or nitrite, ammonium. sulphate, ammoniumnitrate or
chloride, urea and gelatin were un•..favourable tor l.
cae torum. growth and did not p~2’Dlit any growth when used. as
sale nitrogen source in the medium.
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d) Highest sporulation (sporangia) was found at 80 % R-Hand
oospores at 10C % RB, while no mycelial growth was noticed
at 14.5 and 50 % R.H.
e) The fungus, !.cactorum, had a wide range of hosts in
Egypt. It infected fruits of tomato” appl-e., leiloB., ~ve1
orange and potato tUbers, however, with different degrees
of sympt:”GIIS.. and disease severity.
f) The effect of infection with Eocactorum on strawberry
fruits revealed that inoculated fruits contained. high amounts
of dry weight than un-inoculated ones. In this respect,
Aliso (less susceptible cur tivar) gave higher dry weight in
both inoculated and un-inoculated fruits on contrast with
Balady ( the most susceptible cultivar) cUltivar.
g) The percentages of infection with ..I.caetOM increased
with the increase in WHO ( Water -lIDitl:f Dg - CapeCi:tT”). All
fruits that tOUchedthe soil were infected with l.cactorum.
4) Strawberry fruits of Balady cultivar were the mOst
susceptible to infection with the tested fungi, whereas Aliso
frui ts were the least susceptible and ..riogs and Fresno
were :~derately resis1antto infection .However, ~ection .
was less in the pre-mature fru1 ts than in the IDB.ture ODeS
in all tested c~~ivars.
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5) a. PME, PG and ex enzymes activity increased by prolonging
of incubation period of inoculated and un-inoculated
:f’ruits and also by increasing time of rese tion fran 5 to 60
min. at 30°0. However, the actiVity of these enzymes was
higher in Balady (most susceptible) ~
’least susceptible) cultivar .•
than .Aliso
b. Polyphenol oXidase and peroxidase enzymes activity
increased by increasing the incubation periods prom 2 to 6
days, and, also in inoculated fruits than un-inoculated ones. ”, ,,’.”.(.’ i : ”
H~’;’~ve;, Aliso (least susceptible) cu’LtivaJ; contained higher
enzymes than Balady (most susceptible one) •
6) Soluble carbohydrate contents were higher in inoculated
frui ts with !:.cacto~ than in un-inoculated ones especially
atter 2 and 4 days. Total sugars reached its maximumafter
4 days then decreaced again. However, Aliso (least suscepteble’
cuI tivar) showed the lowest amount of reducUJg
sugars at,ter 2,4 and 6 days, on contrast with Balady (most
susceptible one). In this respect, non-reducj,ng sugars
increased in Aliso cu1tivar, on contrast with Balady one.
7) a. Qualitative analysis of free amino acids proved the
presence at 17 amino acids i.e. Cystein, Lycine, Histidine,
.’\.spartic acid, Serine, Glycine. Glutamic acid, l’heronine.
Alanine. Proline, Tyrosine, Treptophan, Methionine, Valine.
Phenylalanine, Leucine and Iso-leucine of all straber17
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cuI tivars in un-inoculated and inoculated fru1 is with
~.cactorum.
b. Also, quantitative analysis indicated that Balady
cu1tivar contained higher amounts of free amino acids
than Aliso one. Moreover, total amino aCids increased in
strawberry fruits inoculated with ~.cactorum.
8) a. Total phenol content increased in fruits inoculated
nth l.cactorum compared with the un-inOCulated ones.
However, Aliso cultivar contained higher amounts of total
phenols in both inoculated and .un-inoculated fruits than
Balady one. Similar results were obtained as regards free
phenols and ortho-dihydroxyphenols.
b. As for conjugated phenolsJ their amounts increased or
decreased during the development of disese with no general
trend f or all cuI t1 Vat’s.
9) T.S.S. contents increased in strawber:ry fruits of
different cultivarsinoculated wi th~.cactoram. c01lpared
with un-inoculated ones.
10) Titratable acidity increased by prolOnging incubation
periods in un-inoculated fruits compared with the inoculated
with 1-9actorum ones.
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11) a. -In-v,itro· studies, ’Benlate, Bavist1nand Tecto fungicides
gave best control against l_cactorum on PD4medium.
While, Hespor, Difolatan were intermediate in th.eir effect.
In this respe’ct the following fungicides 1.e’., CClDazin
Daconil 2787, Dithane» 45 and Topsin]l were les8 effective.
b. In greenhouse, all the abovementioned fungicides were
effective ·n controlling leather rot (l.cactorum) and
Daconil 271!rT t Dithane 1445 and D1folatan were the most effecti
ve.1’uDg1cides.’ Bespor, Gom.z1n and Bavistin were le8.
e~e~~ive.On’the other hand, ~enlate, !opsi~.and Tecto
~re intermediately effective.
c. UDder field condi tiona.,i t was found that among nine
fungicides, Docoml 27Ent Dithane M4e5 and D1folatan gave the
best control of fruit rot diseases and gave the highest yields
during the two seasons 1979 and 1980•.
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