الفهرس 
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Abstract
The present invedtigatton was planned to study the causals of leaf Spot diseases of tomato plant and the effect of sothe phYsiological and biological factors governing the outbreak and ,,ontrol the diseases cause by Exserohilum halodee (Dre6h81.) Leonard & Suggs and- . Ulocladium botrytis Preuss 6n tomato.plants. The finaings cat be summarized as followS:
1- Two isolates from both Alternaria porri sOltni
and Ulocladium botrytis and one from each of ExserohilUm halodes„ Cladosporium oxysporum, Curvularia verruculoe4 and Alternaria alternate were isolated from spotted ,1
tomato leaves.
2-Pathogenicity studies revealed that E. halodes U. botrytis isolate No.1 & No.2 were the most virulent fungi. The first fungus caused the highest disease itdex under lap. conditions whereas, U. botrytis isolate No.l caused the highest disease index under greenhouse conditions.
3-Czapekts medium Was the’best one for fungal growth while Brown’s medium vas the lowest in this respect. However, PDA medium gaye best sporulation of all tested fungi and glucose peptene was the lowest one in this respect.
4-Sodium nitrate,: peptone and gelatin were the beet nitrogen sources for linear growth of E. halodes, and
U. Imalis isolates to.1 sad No.2 respectively. Howeter, asparagine0 sodium nitrate and gelatin were better for sporulation of tht afchiemestioned fungi respectively. Ammonium salts (sUlfate, nitrate and chloride) were uh-favourable for both growth and sporulation of all tested, fungi. Ammonium nitrate hare a moderate effect in thil
respect.5- Growth and sporUlatida of E. halddes were better on sucrose and xylose. towevert glucote and dextrine were. the best for both isolates of U. botrytis.-Arabinose as sole solirce of carbon supressed both the growth-and ’sporulation for all.the tested fungi. 6-E. halodes grows better under all tested light *ave-lengths and reachs’its maximumunderred light wave lengths its sporulation was suPported under green light follo*ed by complete darkness. However, darkness’, red and green light waves *ere faVourable for both growth and sporuIA-
tion of botrytis iSolates.:
7-Leaf leachates of healthy Super Marmandei the resistant cv., contained the highest amounts of both tdtal and reducing sugars on contrast with the auseplible Pritchard cv.. On the other hand, leaf leachates of Prit-chard eV. enhanced both the percentage of spore germination and germ-tube lengths of all tested fungi, meanWhile, there were no significante differences between those of. sulier Msrmande cv. and distilled water in this respect.
8- Brestan 60 WP was thfl most effective fungi-cide.and checked both linear and amOunt of growth of all testea fungi at the concentration bf 100 ppm followed by DitAane Z 78 in case of P...6 haIodes and isolate No.2 of U.botritis and Dithane M 45 tor iSolate No.2 of the last fungus concentration of 6400 ppm. However, fUngal growths of all tested fungighto Were 2.esa affected by the tested conden7 trations of systemic tungicides. Topsin 50 WP followaa
by Bavistin 50 W11 were the most effective syst,emic fIzA4- cides at concentrationa of 6400 ppm against E. halodea
and U. liotrytis isolate No.1 and folloWed by Vitavax /5 WP
in caso of isolate No.2 of the last funguS at the same.
concentration.
9. Both spore germination and germ-tube lengths’wSe
completely checked at 4oncentration of 1, 50 and 25 ppia
of Brestan 60 WP, for E: halodet, isolate No.1 and N642
1 of U. botrytis respectively. Dithane Z 78 ranked the
second at the rates ofr750, 50 and 50 ppm respectivelY
Both Bavistin 50 Wp and Topsin 50 VP reduced spore germination and germ-tUbe longths of E. halodes till -the concentration of 10 ppa then increased again. However; these measurments’were completely checked at 25 ppm of Bavistin-50 WP and 750 ppm of Topsin 50 W for isolatei
No.1 and N6.2 respectiVely.
10- All tested fungi could produce toxic substances on liquid Czapekts medium. However, isolated.crude
toxin($) could podu $ typical symptoms of leaf spot diseases Similar to these produced by fungal infectio$. Leaves of Super tlirmande eV., (riaistant) was more affected with the isolated fungal tOtins than Pritchard one (susceptible cv.)The different extracti=s of fungal crude toxin(S) of all tested fungi could affect a wide range of host plants i.e. Broad bear!, gqulsh, Eggplant, Pepper, Olive, Durant°, Ficus, Btegnodia and Dedonin. The effect of different crude toxin(s) ranged between a limited circular black ow brown spots on leaves of Olive and Ficus resfect-ively and irregular and wider on leaves of Begnonia.
Root-formatiOn on tomato cuttings was completely bhecked and inhibited in ease of isolate No.1 of U. botrytis-crude toxin(s) followed by crude toxin(0’ of E. halodes. The increasing in the concentrations of fungal crude toxia(s) caused rapid wilt symptoms especially in case of U.botrytis isolate No.1
Percentage of tomato seed germination and length f seedlings were greatly reduced by treating seeds with fungal crude toxih(s). The reduction increased with the increasing in crude to ’n(s) concentrations. Also, filngal
toxin(s) clearly reta ded the time required for tomatb seedling emergency especially with the higher concentrhtion (800 ppm) of E. halodes-crude toxin(s)’
11- All the different tested fungi were able to degrade and utilize pectin, cellulose, starch gelatin and casien
when grown on media cantai ing any of these compounds’,
12- Ict ’Vitro hoth PG at.d Cx enzymeA were most act Ve at a wide range af pH valuta (4.0 to 8.0) especially those of isolate No.1 and No.2 of U. lactx_Sie.. However, pH 6.8 and 704 ware moro favauraW,e for B. haiodes.
The relative activity of fungal PG and ex enzymbs increased with the increase in time of reaction as well as the increase in culture age. E. halbdes showed the lower activities of both enzymes in itb culture filtrb,tes at all culture ages. All tested fungi could be induced to secrete big atountit of these enzymes by growing th6m on certain specific media.
13- Both PG and Cx enzymes were detected in both healthy and artificially inoculated leaves of Pritchai’d and Super Marmande eve. However, infected leaves shoWed higher actiliities whi was 4 to 6 times that of the healthy oneS. Super rmande, (the resistant cv.) showed lesser activities than Pritchard ay. (the susceptible one)
in this respect.
14- Peroxidase act vity was detected in both mycelial matrix and culture fi trates of all tested fungi, hovhver, its activity was high r in the first one. Also, the high-est peroxidase activity was detected in 21 days-old mycelial matrix. As for polyphenol oxidase it was net detected in either mycelia or culture filtrates of any
of the tested fungi.
In VIVI. the healthy ieaves of the resistant Super Marmande dt. shoWed high peroxidase activity than the susceptibie PritChard tv. eroxidase activity generally increased in infeeted leavee of both cses., after 7 day* from inoculation. then decreesed with time. Similar tic:41d was noticed as regardi polyphenol oxidase activity.
15- Brestan 60 WP Was the most effective fungicidei as : at-
it Checked qic activities foe 50 ppm after: 4 hours for
B. halodes and isolate Nb.2 of U. botrvtis and:at 100 ppm
!for isolate No.2. Dithane t 78 ranked the second in:this respect: HoWever, Ct activities were much tolerant against’ Bavistin 50 and Toptin 50 WP. In thiELrespect PG eartiv-• ities were more sensitive to fungicidal action than the Ox ones,. there Brestan 60 WP at:the rates 5 and 10,Ppm checked.. PG activities oft. halodes and U. botrytis isolates.respeotH ively:Topsin 50:0 and Bavistin:could completely check PG activities at’ 50 ppm after 4 hoUrs for all tested fungi,
16-Inoculation with the different tested fungi caufied increases in the Percentage of dry weight matterj espeeiallyi in case of super Marmande cv. after 10 days from infecaon.
17-Both reducing a total sugars.percentages increased! greatly after infection with any of the tested fungi ill case of the reSistant -Super Marmande cv., on contrast With the susceptible Pritchard cv., As regards the non-reddoing sugars, it was greatly increased in Pritchard cv. aftet
inoculation with both isolates of U. botrvtis then decieased with timei
18- Free pheno s were produced and accumulated at
a faster tate in 8uperNartande resistant cv. than tha-, of Pritchard susceptible et. As regards the Conjugated
’phenols an oppollite trend in both tested cvs. was noticed4, except of leaves of Pritchtrd cv. infeeted With .B. hatCdes’’ Free phenols and Ortho’dihydroxy phenols decreased ana conjugated phenolS inereased after 20 days from inocula-
tion with any of the tested fungi in case of the resittant-cv.
19- DiSeaSe incidenCe increated progressivelY by the. increase in inocUlum potential, however, .tbeHincrease *as not proportionally parallel to the degree of inoculUm at
the three highest inocUlum concentrations.
20- Super Marmande Cv., among the tested cvs., seethed
,to be the most resistant one. whereas, cultivars Aoe and
1
Strain-B rankS second to it respectively, However, Pritchard’ .ov. was the most susceftible one in this:respect. .
High relative Humidity with warmth conditions se ted 4 .1
to be nesessarttor iftbreasing disease index. The retistant Super Marmande cV. showed slight disease incidence unaer these conditions.
21-The percentage disease index increased with the increase in plant age22-Systemic fungicides, Bavistin 50 YIP and Topsin
50 WP could persist on the surfaces of sprayed leaves
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till the 30 th days from straying. However, Brestan 60 WP! persist till the 10 tri day, whereas Dithane Z 78 was the least fungicide and cOuld nOt persist More than 5 daye especiallY with the highest concentrations of 1500 ppM2
23- In pot experiments, !)ontact fangicides.i.e. Brestan 60 WP and Dithane Z 78 were most effective to prevent disease index and perdentage of diseased leaves when eed just before inoculatiOn with any of the tested fungi.
Disease index gradually increased by increasing periOdd between fungicidal application and fungal inoculation. However; little lei:Acres:ties in disease index occurred when inoculation was applied 5 to 10 days after fungicidal
application.
On the other hand, syStemic fungicides i.e.Bavis ha 50 WP and Topsin 50!WP ehowed.opposite behaviour in comparison with the ’contact onee. Disease index and Or--
1centage of diseaeed leaves gradually decreased byincreasing
!
the period between fungicidal application and fungal . infestation. The bestresults for disease control were obtained when Bavistin 50 WP or Topsin 50 WP was sprayed
on leaves 20 days before inoculation.
24- In pot experimet Indol Acetic Acid (IAA) gave
the lowest disease indeX when used as foliarspray, 30 days before inoculation with E. halodes at 100 or 200:ppm followed by MR-30 T at 100 ppm, but the latter was the
best either sprayed at 5 or 30 days before inoculation
with any of the tested fungi. Alar (B-9) at 200 ppm Was the best growth regulator When sprayed 30 days before fungal ineculation oontrast in the case of 15 days
which cauSed the higheat dieease index. On the other hand,. GA3 caused high emease. index in all ca es either used 15 or 30 days before fungal inoculation.
25.o. In pot experimeht, addition of Amonium nitrate Calcium super phosphate or tetassium sulphate singly decreased the perdentage of disease index of all testet fungi. .As regard0 B. halodes the best results for ite
dontrollaenbtained with addition of N3P2% 00 gral:pot)or N3131Ki i.e.(2.25 :0.75 .:0.50 gram:pot) in both,: tested cvs. respedtiveli. However% the addition of late]. Pi singly or lyi i.d.(1.50 : 0.50 gram:pot) increased:Seas. disease indek tnit’s miximum in both cvs.-As for infeCtion with isolates of U. botrytis, the
. -
increasing in leVels ofN with,P fertilizers reduced
’disease incidence, alsol N2 (1.50 1.50 gram: Pot) or N3 P2 with or without K fertilizer gave .the best reSUlts in this respect. PlantS withoUt fertilizers N P. K
0 0 0 (without any fertilizers) showed the highest disease index.:
26- Under field conditions spraying with i375 PPm 0 active ingrediente Ths . of Bavistin 50 WP and Topsin 50 WP wis. effective to prevent disease index. However, the highest
,
yields were obtained with 750 and 1500 ppm of both fungi-,
sides respectively. Brestan 60 WP gave promiding results ’ .
for disease control and yitld when applied at the ratet of 1500 ppm and 750 ppm in 1978 and 1979 seasons
respectively. 27s Under field experiment IAA followed by MH-30T gave the lowest diseaite index respectiVely. HOWeVer
GA3 caused the highesi disease index in both tested oil. As regards the yield HH-301 followed by IAA was the hest in season 1978 and IAA followed by Alat (B-9) in season 1979. On ths other hand, the lowest yields of both’teeted
cvs., was associated with GA3 treatmsnts.28- Under field conditions, the addition of N fertilizer with or without P or X reduced disease incidence, also Pi level gave best results than P2 level. HOWeVert the incr. ease in levels of all[fertilizers increased the yield
per feddan than tit. treatments without fertilizers. The least disease index wae obtained by addition of N2 P2 Xi
(300:000:100 kg/feddan) followed by N3 Pi Ki (450:1501100 kg.:feddan) followed N3 Pi Xi for Super Marmande cv. However, the highest y4eld from both eve., was obtained at the rate of N2 P2 X- (300:300:100 kg./feddan).