الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
1) Four isolates of Botrxtis alU1 were isolated from neck
rotted and aJ.so from neczo ta,c blighted leaves of onion
plants collected from different govettJOrates of Egypt.
2) bee d1ffezent isolates we:re virulent to both bulbs
and tmnapla,nts. Also an assooiation of neck rot and
leaf blight or spott1.ng was observed.
3) leaf spotting occurred on onion plants sprQ’ed with
the f11 trate of J:. J,lJil! grown on Dlltrient bro tb. dextrose
l1.q~ mediumwbile the oultural filtrate of
onion extracts gave oontinous blotch”. A s1~1cant;
~lation between growth temperature and viJ.’ulence was
found. At the same time the fungus grown at opti8ln
temperatuxe (20 00) produced the highest number of
leaf spotting. b highest number of spots occurred
also on plants sprayed with filtrates of ftJDgt18 grown
atp pH 4.3 - 5,2 as it gave best rate of growth.
Iesponse of wounded potted plante to fUDge) filtrates
was not affected by various incu.ba’tion ~rlods,
However, six days incubation gave lDfIxhnUID mte of
growth. There WJ.8 a high positive correlation between
amount of growth of isolates and their v1J’.’u.1e:oceon
the fo 11age•
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4) .s vim, screening of :Benlalie, :Bavistin, ~psinR 50,
Ba.S3050, plantvax and ,J)1tbane II 45 on j. §lli1
:revealed that Benlate, Bavistin and· TopsinR.50 were
the most effective fungicides i.J:lhibited mycelial
growth, sporulation, and sclcrotial formation at the
concentration of 1 ppm. Inhibi tion of mycelial growth
and sporulation oocurred at 100 or 200 ppm of plantvax
or :.IU.thane M45 respectively .•
5) High PG activities _re assoOiated with all isolates
.filtrates. Bani-Buef isolate (the most virulent) gave
the highest ax and Pl4E activities, while Gisa isolate
(the leQ.8t virulent) showed decrease in OXand PIlE
activities.
6) .AlUgb. percentQe,e reduction in pectin v1sooaity by
cu1tural filtra.tes was obtained at 20 °C (the optimum .
tempero.ture for fungal growth). CellulalJA activity
showed sim:1lar results in addition to a high cormla:tion
between temperature degzee a.nd enQlDe activity. On
the other h:Jnd, HIE shone~ to :...emo~ active af
1.0 - 15 °0 •.
7) Poq@iQ.lf’..Otur..i:lQS9 (?G) prc’:uc’tion wo.s greatq reduced
in culture by arJdi ng certain fungicide. to tbe medium.
Be.nla.te, or .J)i..thaneeffectiveq inhibited PG
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production in cu1ture. Oncontrary, plant’v:»x showed
ver;r little effec~ in :tteducingPGproduction. Adding
’BenlD.teor plontvax to tbe mediwn consiaemb~ X’edaoed
BlE p1’Oductlon~ Oellulo.se o.ctivit1’ was reduced in
filtrates of j. gll1i wae~ )~tvo.x ortithane II 45
.•• incorporated in the filtrate. 0311u1aBe activity
was little affeoted bY’adding Eenlate to the fil1im.te.
Adding different concentrations of Benlate, plantvax
and DLatha.ne II 4-5to the fungal £iltratea did not .reduce
PG o.ctivity, However adding Benlate or plantvax to
the filtrate affected HIE aDtivity to some extent.
8) Pec”tinmetb3’leB’tro.se.Po~galactu.rono.se. and cellUlase
activities 118m aasocia..ted 1d..th onion bulbs aDd leaves
infeeted with B-. a-WJ.. production of BQ.i:, PGt aDd ex en.,mes •• mom a.ctive 1n infected tissue than in
haa:l’t~ ones. Inc1’9o.se _s obVious 1n PGfollo_d
by ax, while a slight inc.J:.’8l18nti no’ted for J’IE,. lelative
activities of PG, ax and PIlE in the onion blighted
leaves wexoe greatq increased than in the ~al~ ones.
9) Isolatea ditf’e:red in peroxidase utiUr.Lt,. in botll
myce J.1um. and cul.tuJ.’O.1 filtrate. G1.sa i801.o.te~_d
the most actiw pexo.x:ld,.,. in ’t.be t’t1nga1 IQ08lium
wbile amnd-.e~isolate •• mo%8 uti:ve ’than other
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1
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isolates in cultural. fi1trates. Also tbe isolates
varied in activity of phenol oxidase in myoel1Q1Il and
cul~ filtrate. Peroxidase and phenol o~dase
a.ct.iN’1-17.Lea W9re more in the myoeUum.than i.n the
fUtm,-te-.
10) No diffe1”eD.OO in pel.’Ox1da.se o.ctivity was found in
bao.ltby bulbs of transplants ot ~b_ed go~den (less
susceptible) and Giza 6 (swtCeptib~) onion varieties.
,Actin ty of pheno1 ox1dase in ~br1ed golden 1188 more
than 1n Giza 6 in bea.1tby bulbs of transpl..-o-. It;
was found that tbe i.D:feotion with -B” allU incren.seJ the activity of tbe t1io en~s. in both tested
vn.rie ties.
11) stu.03of inoculum. poten1iial in gree~bDUSe indicated
th¥t in.creosing the iDoculum amounts Of -B. a~
rEIsulte d in an ini ti..o.l l.1Dear increase in the disease
incidence •
12) Benlate (at 2%) and :ea.v1.stin (at 5%) gave a. cample ta
pmteot1on of neck rot iDfection in pots while Topsin
R
50 (a.t.5%) redueed tl:ae infection.
~3) vcr1atol mo.cti.on to infeotion ld.tb .I- .aJJ-:i.! iud1-eo.ted
that twelve onion varieties WBL’8 sU808p’tible to irdeot1on.
!Ibe de~ ~ disease reaction ranged :from
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_._. --- ._-- ,--- _. -_ ....~
I
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75 to 100 %. Hybried goldetl. and H. tropieana sho’Wed
the least percentage of infeo:ti.on.
14) IafIuence of irrigation on neok rot in the field and
storage declared that infection of onion bulbs with
j. ~ was fo.vow:ed by increo.sing number of irrigation.
o.lso the yieJ.d, and average weight of individw11
bulb were increased ~th increase in number of
irrigation. ~ percentage of l.’Otted bulbs occurred
in. ’tbose wa.texed on.JJ’ once.
1.5) llUect of m.a~i.ty of bulbs on the incidenoe of neolt
rot in the field and storage showedthat a. :reduction
in pe :tOen’ta.ge o£ infection (iDsgJJ:l fi.oant). yie ld and
average weight of bulbs at; the eo.rlJ” l:IaxWsting time,
memllidle in storaosi’ immature blllbs we.re more su.scepti.
ble to neck rot than the fully mature ’.
16) .Evo.1ua’tionof dipping ,’tmJ18P1tu:lts ODd bu.lbs in certain
fungic.i4ea agD,inst neck rot di8ea.se on onion for
(bulbs) ond (seed produot1oJ1) undBr field OOnditioDS
reveo.1ed that Benlate and Ba.vistin were the most
effect!Ye fungiOiQe8 wbils !Jbp1nBSO reduced the
percent.o.p 0% i.n;fect:1.on to a. J..ar£9a degree.
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- --_. --- ,,_ .. ~- .._-~- -,... _- ...
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].7) ~ at sprOJing of Eenlo.te, ~psinR 50, :.mdBavistin
can be used as a protective fungicides during storage.
!lbe timing of preb.tJ,.rVest applica.tion ho.ve a. slight
effee’t on tbe reeponse of bulbs to fungici.dD.l appUoo.-
tion. Tba fungicides reduced no.tltttll infection
sl1gb.tly while they showed sabstontial inhibition in
case of artifioially inocul.o.ted bulbs