الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
A severe ~ead roi; disease of Brassica p d oleraceae L.
vex:1-.Q.~1J1~;:.~:t!c”-u~tivex KaJrira Hagin was encountered in the
f’arns o.f Faculttr of Agricult1..1re, El-Minya University and
Secondary E’choc~of’ ~iculture ai; El-Minya. The purpose
of: this investjlgation was to iden-tif’y t to study the properties
of, anc] to find sone contrrol. raeasur-es against, -the
pathogenic OrgE~sn (s) •
Results c.oul.d be aurmaz-Lzed in trhe f’olloings :
1 - Ten bactrerh.a were’ isolated froD ten naturally infected
cabbage p]~ants. According to norphological, physiological
and pa”tho]~ogioal: characters theY could be classifi.ed ~to
3 groups ~Isolates of group 1 ( I and II ) and group 2
( III to VI ) appeared to be representatives of the
genus -Erw-:i.nia, whereas those of group 3 ( VIr to X ) of -
the genus
. ..
P,seudononas •
2 - Isolates e,f groups ~ and 2 are non-sporeforDing, single
straight rods neasuring O~6- O~7:x:O!8 .:. 0.9 JL (group 1)
and 0.5 - 0.8 x °.95 Jl (group 2), oot11e by 2 - 6 peri- ..! • ~. +” . .
trichoUB :J~lagella, surrounded by a sline :J,ayer, Gran -
- 120 -
negative-. Not lipolYtic.- Donot hydrolyze starch~ Reduce
nitrate to nitrite; indol negative~ Produce acid and gas
fron glucose, frutose, and galactose. They are facultative
aerobes. Not pigne:!J.ted •• Produce ~S
The PseudoDonas isolates are non-sporeforning, single
straight rods, so:;-~etinesin pairs or short chains 1 neasuz--
ing Cl ~.lI._ 0.5 x 1.4- - 2~2JI, ootile by 1 - 3 polar flagella,
non-eapsulated, Gran-negative~ Not lipolytic, do notr hydrolyze
starch~ Reducenitrate to a:ononia, indol negative~
Produce acid but no gas froD glucose, fructose and galactose.
They are strictly aerobic and produce fluorescent green
pignent. Donot produce HZS •
The nininun, optinUD, and naxinuo tenperatures for
growth of the tested bacteria are : 5 - la, 30, 35 - 40°0
for isolates of group 1 (Erwinia); (,5, 30, 35 00 for isolates
of group 2 (Erwinia); and 15 - 20, 30 ., 35,) 40 °0
for isolates of group 3 (Pseudononag).! The therual death
point of all Erwinia isolates is 55 °0 whereas that of
E!ieudononas isolates is 57 °O! The optiDUD pH for growth
of the E-r-Wi-n-ia- isolates (I and III) is 6.8 - 7.8, but for .’
the tesiied Pseudononas isolaiie (VII) iii is 6.2 •
Good growth of all isolates was obtained on nut1’ier:~
-glucose agar, nutrient - glucose agar c.ontainD1.g0.3 %
yeast extrac~tt glucose 8.s,?aragine agar, Bouillon glucose
(particularly if supplc:13~1ted.with 003 % yeast extract),
anJ. glucose asparagine E0:i_~tion.They utilized different
sug3,;CS~ alcohols, as well as citrate end tartarate •
0~narcharacteristics are also reported ~
The OJ:,ganiSIJBdo not deconpose cellulose, but rot
potato slil~es. They cause soft roi; end necrosis in lleadB
of infected plants !
3 _ MOrphological and physiological characters revealed that
, isolate:s of group 1 and 2 <lOJdbrnwith !t”wip.:ha cf&ROtovora
var. carotjovora, whereas ’those of group 3 with Pseudomonas
po1;ycolor • Differenc es between 1.s01a.te8of group ]. and,
group 2 e:x:isted D,ElinJ.y in viruJ-ence and sligh”tly in physiological
characters 1
4 •• Artificial inocUla’tion of cabbage heads reveaJ..edcertain
differences as regaxds the severity and type of rot symp.-
tons incited by different isolates • According to -these
differenoes iso1ates could be classified to ni1d (group 1)~
noderate (group 2) and severe (group 3) ones. Rei; symptoDS .
were associated wit:a light brown discolouration (groUl)S
1 and 2) or with blackish violet discolouration plUS
tissue necrof;,is (groulJ 3) •
5 _ Host range s1;udyrevealed that the tested isolates (I, III
and VII) oou.Ld. produce rot synptorJ.s, but varying severity,
in -t>(t-3 following hosts : nai.se , lettuce. tonato, potato t
egg:;;J..ant, squash, raddish, and carrot. The strain of E·
£olycolor (no, VII) appeared to be of wider host range
in cot>.parisonwith the 2 stra.inS (I and III) of !.!!’\f:s>tovora..
r-t infected calla and cau1.iflower whereas both isolates of
Erwi.IJj,a did not •
6 _ Clear hypersensitive reaction appeared 24 nouns after injecting
White Burley tobacCOleaveS (in the nesopbyll)
with the E5~E1.udoDona.§isolate (i.e., isolaiJe VII) only,
whereas no synptons appeared in case of inQculation with
1ihe 2 isolates of ~a • •
7 _ It waS foutld that -the head (leaves) of Kahira Hagin cabbage
was the nain route of infection with the s1irain of E· polZceier
(isolate VII) •
8 ”:”’When’the bac~’terial 1s01a1;e5It III,. and VII were tested,
on nutrient.~glucose agu;r:J against ea~h other :for possible
antagonisti(} action, 0[.!-1:2”.301ate VII (p.a.6.udoinona.s) ’. ’
appsar ed to have inhibi’~-c,ry effect against bo-th o’ther ones.
When studying the interference be’tween isolates in
g:cs’~.””’.J1(’usetests ,. it appeared that simu):taneous inoculation
with any of the Erwinia iso1at es a:wl ”the ~seu.,d01l1Ona.S stra.iu
resulted Lr, a reduciiion of bacterial ro’t symptoms as
compared to inocula-tion with any of iih~ three involved
isolates when tested alone.
9 _ Under the ,~onditions of the present work, the Pseudomony
isola-te was transmitted among cabbage plants by ’the cotton
leaf wormbu’t not by cabbage aphid •
10 _ Enzymatic activities study revealed that all tested isolates
of !~a and Pseudomonas(i.e., 1s01a1;e8I, III
and VII) were pas! t1 ve for pec-tolytiQ enzymes (11quefa.(rtion
of pectattl gel and production of PME,PG, and pp) and for
ca’ta1ase production~ With concern to .~ucosidase t -the
Erwinia 1aolates were the only ones which showed ac’tivity •
11 ....Tests on toxicity of some phenolic compounds (i .•c ~’ pyr ..-’
catechol,resorcinol, hydroquincne, and p-b6J’zoqumone)
to the bacterial isolat,:;s .1\l III and ’III r-evea’Ledthat the
nost i...”’1.hibiTO:r,8:yubste:t’.L·~s v:’:”T:e:p-benzo’luinone followed by
l:.~;~ited thE: gr-owbh of all .3 tested isolates at 125 ppm,
Whc.l’(’&;3 hyd.~cquinone and pyrocatechol suppressed 1:ihe growth
of tne :P• seudomonas.isolat e at 125 ppmand of both. Erwinia
isolates at 250 ppm .0
12 -.Ex:periments on the !n vitro and in vivo effec”ts of 2 antibiotios
and IS fungicides against the bacterial isola1ies
I ,III and vrr showed that :
i •.Oxyte-tra:3YCl.i.na ohloride and N,eomyeinsulpha:te were
more effecti’ve in inhibiting bacterial growth than any o~
-the 1iesed t’ua.gicides (i~e., Dithane Z-78~ Oopper olQ’Ohlodde,
~3rraclor, Beillate ~Bavistin, and Topsi.n~~ Oxytetracycline
chloride caused complete inhibition of :the Erwinia isolates
at the lowest ·concen1;ra~.i.on used (10 ppm) atl’:of ’the Pseug.pmoW
isolate at” 25 ppm~ whereas lfeom;yc.i.nsulphate incited
such eUect to the former isolates a:t 25 ppm and to
the la’ttero,o.e at 50 ppm. The most effective.fungi.cides
. (Dithane z.:.78 and Copper oxychloride) shoWed such etfect
at consider€l>ly higher rat es (200 - 500 ppm) ~
ii _Themoflt effective, according to laboratory tests,
> • compoilllds (: .• e., oxytet:..:’ac~tcline chl,)ride, Neomycin
sulphate, T.:Lthane Z-7D) and Copper oxychloride) when
applied in 3ingle-spr3J- t::’ea1imentsconsicierablydecreased
:.L~~.f9ction 0 f cabbage plants with isolate I or VII... In
al~:J.sl’t all cases, disease severity decreased w;.th increasing
the concentration of the compo1.md~
The COIlLPOunds varied as regards the best -time of
applioation. With both pathogens, fungicides gave best:
results whon sprayed 3 days before inoculatioJl- !oth antibiotics
we::-emos:t effective aga1nSt the ErRini.a isolate
when appli’3:d ~ days before inoCulation, but againS’t tl;Le
Pseudomonas.isolate when used one day af”ter inoculatioJ\. .
The aDtib1ot1os Oxytetr~1ine cbloride was the moat
effective compoundused; in 1974 it comp1e-tely :i.nldbited
infect-ion incited by either isolate when spr8J”ed at 75
ppm~ days before, or 1 day after, inocula1iion and in
1975 it el1iher strongly or oompletely inhibi”ted i.Dfeotion
at; the nentioned cOI1cen:tra”tionand times of applica”tlon.