FACTORS AFFECTING RESISTANCE OF TWO OLIVE CULTIVARS TO LEAF SPOT DISEASE IN THE NORTH WEST OF TUNISIA ABSTRACT

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1 Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 FACTORS AFFECTING RESISTANCE OF TWO OLIVE CULTIVARS TO LEAF SPOT DISEASE IN THE NORTH WEST OF TUNISIA Fethi Ouerghi Institut Ntionl Agronomique de Tunisie, Université de Crthge, TUNISIA Ali Rhoum Institut de l Olivier Tunis Sttion TUNISIA Neil Rss Ecole Supérieure d Agriculture du Kef Kef, TUNISIA Itissem Hennchi Institut Ntionl Agronomique de Tunisie, Université de Crthge, TUNISIA Bouzid Nsroui Institut Ntionl Agronomique de Tunisie, Université de Crthge, TUNISIA ABSTRACT Evlution of the incidence of the lef spot disese cused y the iotrophic pthogen Fusicldium olegineum on two olive cultivrs (Ole europe L.) ws crried out during six yers (29/215) in groves locted t Touiref (North West of Tunisi). The studies focused on Meski nd Chetoui cultivrs. The evluted folir incidence of disese ws nlyzed in reltionship with some fctors. Disese incidence vried gretly mong the tow cultivrs sumitted to similr conditions. Meski is the susceptile olive cultivr grown ut Chetoui is more resistnt to these pthogen infections (R² =.94). The otined results reveled tht disese incidence ws correlted with the height of the trees (R² =.8), with the direction (R² =.82), with the lef ge (R² =.78) nd the reltive humidity (R² =.91). During our studies, we were ttempted to collect the fllen leves under trees to survey the development of the fungus Fusicldium olegineum, ut no sexul form ws found. Keywords: Disese incidence, Fusicldium olegineum, olive, resistnt, susceptile. INTRODUCTION The olive (Ole europe) is the most importnt olive-growing in Tunisi country where occupied round 3 % of its cultivted lnd (1.68 million h). The nnul production is recently estimted to 79, t of olives in 214 (FAO, 214). The olive lef spot disese (pecock spot) is cused y the fungus Fusicldium olegineum (syn Spiloce olegine) cuses severe premture defolition of the olive tree (Ole europe), nd sometimes the deth of the whole plnt (Miller, 1949; Azeri, 1993). Tle olive cultivr Meski nd oil olive cultivr Chetoui re the most growing in the North West of Tunisi. The first one is susceptile to lef spot ut Chetoui is less susceptile. The disese is widespred in the world nd in specilized res of cultivtion of olive trees with yield losses estimted t more thn 2% (Wilson nd Miller, 1949). Moist wether conditions fvor fungus sporultion, conidi germintion nd infection, nd young leves re more susceptile to infection thn older ones (Grniti, 1993). Conidi germintion nd infection required continuous moisture for h nd tempertures rnging from 5 to 25 C (Onor et l., 28). This folir disese is very common in the humid regions of Tunisi nd widespred in mny olive-growing regions, including North West of the country. Infections re normlly ssocited with high humidity nd winter conditions, where high tempertures restrict spore germintion nd growth (Al-khti et l., 2). Symptoms were quickly determined ccording to the method of (Zrco et l., 27). Fusicldium olegineum (syn= S. olegin) is specific pthogen of olive (Ole europe L.), whose development is restricted to tissues cuticle ffected (Tenerini nd Loprieno, 196), s with the custive fungi the scs of fruit (Wheeler, 1969). The nme refers pthogen only the sexul stte fungus. The sexul stge, lthough it hs een suject of some reserch Progressive Acdemic Pulishing, UK Pge 39

2 Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 (Grniti nd Lviol, 1968; Lviol, 1966; 1968; Miller, 1949; Virueg et l, 1999), it is not known, ut could correspond with Venturi y nlogy with other species Spiloce, s with S. pomi, nmorph of Venturi inequlis, cusing the 'sc' or 'Mottled' pple (McHrdy, 1996). The life cycle of the custive gent, Spiloce olegin is dependent on climtic conditions, which the most importnt re temperture nd humidity (Onor et l, 28). According to results of previous studies (Onor et l, 211; Virueg et l, 211), the min risk period occurs during erly spring due to the presence of conidi of the pthogen, fvorle wether conditions tempertures from 15 to 2 C nd wetness durtion >24 h), nd the presence of developing leves (Virueg nd Trpero, 1999). Other uthors hve suggested tht infected fllen leves re n importnt inoculum source ut they did not provide ny epidemiologicl evidence to support this clim (Guechi nd Girre, 1994; Hudson, 1971), we cnnot exclude the possiility tht they might function s n inoculums source under different wether conditions, with different popultions of the pthogen, or in the presence of different sprophytic microorgnisms. Despite its importnce, there is little informtion on some fctors ffecting their development of this disese in our country. Thus, we conducted this ttempt of study in order to contriute in the understnding of the development the lef spot disese nd the effects of vrious fctors environmentl nd host on infection nd development of disese nd olive cultivrs resistnce to lef spot disese. METHODOLOGY Plnt mteril The olive groves were locted in Touiref (in El-Kef t the North West of Tunisi: E; 8.7 N, 516 m ove se level)). Fresh leves of two cultivrs (Chetoui, nd Meski) were collected in spring time, the min period of olive ttck y the lef spot disese, from orchrds plnted in 21, during the sesons eginning 29 nd finished on 215. A totl of Leves were collected from three trees of ech vriety selected nd then stored t 4 C in Crop disese lortory of ESA Kef. The determintion of the percentge of ltent infections of olive cultivrs y the lef spot disese ws sed on the method of (Zrco et l., 27). It consists on immersing leves in 5 % sodium hydroxide solution for 2 minutes t 22 C. After this tretment, visile lesions were more prominent nd ltent infections ppered s lck circulr spots, clerly differentited from helthy green tissue. Assessment of incidence disese for different cultivrs leves, visily infected, were rndomly collected from 2 trees of the sme ge (plnted in 21) for ech cultivr (Meski nd Chetoui). Ltent infections were determined y immerging leves in NOH 5% solution for 2-3 min (Zrco et l., 27). The numer of infected leves ws recorded. For ech vriety, three repetitions were done. Assessment of incidence disese for different level of reltive humidity Trils were conducted on Meski nd Chetoui cultivrs, the first which is highly susceptile to OLS (Grniti, 1993); the second is modertely susceptile (Triki et l., 23). Mesurements of reltive humidity were tken rndomly in ech spring for ll 6 yers y mens of Lutron HT-31F Digitl Humidity / Temperture Meter. Progressive Acdemic Pulishing, UK Pge 4

3 Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 Assessment of incidence disese for different heights of trees A totl of 9 leves were collected from the 4 trees of 2 cultivrs (Meski nd Chetoui). For ech tree 3 leves were collected from the ottom, 3 from the middle nd 3 from the down. The percentge of infected leves. Assessment of incidence disese for different ges of leves 9 leves from ech vriety were chosen rndomly: 3 leves new formed (for the current yer), 3 leves from the lst yer nd 3 oldest leves were collected nd evluted for the ltent infection. Evlution of ltent infections ws crried out y method descried y Zrco et l. (27). Assessment of incidence disese for different directions For the field trils, ltent infections were sed on totl of leves tken rndomly from ech cultivr with 2 leves on per rnch on five rnches selected in vrious directions. The smpling ws repeted three times nd dt were trnsformed to meet the requirement for norml distriution. Fungl mteril Leves fllen down the trees were collected in two sesons in order to study the cycle of the fungus Fusicldium olegineum. In Phytomycology lortory of El-Kef High School of Agriculture conidi were otined from fresh disesed leves of olive tree cv Meski (susceptile) nd cv Chetoui (less susceptile). In order to otin the suspension, the infected leves were dried t mient temperture for 2 weeks nd then stored t 5 C in drkness (Trpero et l., 1994) nd then were gitted in sterile distilled wter for 2 h t 8 rpm t mient temperture. The conidil suspension ws then filtered through doule lyer of cheesecloth to eliminte vegetle mtter (Alonso et l., 26). Oservtions of germintion were done on slides for ech smple. Dt nlysis A dt incidence diseses ws pplied on the nlysis of vrince nd the Men vlues were compred using Fisher protected LSD test t P =.5 (SAS, 1985). All mesurements were repeted t lest once nd results show the verge vlues of experiments. The results were nlyzed using nlysis of vrince (ANOVA) nd Duncn s multiple rnge tests (Softwre SAS System, 1985). RESULTS Evlution of ltent infections of cultivrs Since the symptoms re invisile efore 176 dys fter inocultion, it ws importnt to use ltents infections technique. The results shown in Fig.1 revel n importnt vrition in the susceptiility of the cultivrs to the disese. The nlysis of vrince nd the mens comprison reveled significnt differences etween the cultivrs. Indeed, the Meski cultivr ws the most susceptile nd Chetoui the most resistnt to the disese since 8 % ltent infections were oserved. The However, cv. Meski ws the most susceptile to the disese, with the percentge of ltent infections rnging from 33 % to 52 % (figure 1). Progressive Acdemic Pulishing, UK Pge 41

4 Ltent infections (%) Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, MESKI CHETOUI Figure 1. Effects of reltive humidity of collected leves on percentge of ltent infections of the lef spot disese Vriety Incidence disese for different levels of reltive humidity The nlysis of results showed tht there is high significnt difference in the percentge of ltent infections of lef spot disese etween the two cvs nd different levels of reltive humidity. The reltive humidity is rising more thn the percentge of infesttion y olive lef spot is high. The Meski vriety presents the highest percentge of ltent infections with out 65% t RH>8%. If is less thn 6%, leves of the two cultivrs presented minimum lesions. Progressive Acdemic Pulishing, UK Pge 42

5 Ltent infections (%) Ltent infections (%) Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, c HR 4-6 Meski HR 6-8 Meski HR >8 Meski Figure 2. Effects of relive humidity of collected leves from Meski cv. on percentge of ltent infections of the lef spot disese 16 Reltive humidity (%) c 2 HR 4-6 Chetoui HR 6-8 Chetoui HR >8 Chetoui Relive Humidity (%) Figure 3. Effects of reltive humidity of collected leves from Chetoui cv. on percentge of ltent infections of the lef spot disese Progressive Acdemic Pulishing, UK Pge 43

6 Ltent infections (%) Ltent infections (%) Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 Incidence disese for different heights of trees Mesurements of ltent infections percentge for three different level of tree height showed significnt differences mong the sme cultivr nd etween cultivrs. Ltent infections rnged etween 3 nd 11 % for the cv. Chetoui nd from 2 to 6% for cv. Meski. In ll cses, Chetoui cv. hd the lowest ltent infections percentge. Meski hs the highest percentge of infected leves for ll levels of height Height level Meski Medium level Meski Low level Meski Height Level of leves Figure 4. Effects of height level of collected leves from Meski cv. on percentge of ltent infections of the lef spot disese Height level Chetoui Medium level Chetoui Low level Chetoui Height level of leves Figure 5. Effects of height level of collected leves from Meski cv. on percentge of ltent infections of the lef spot disese. Progressive Acdemic Pulishing, UK Pge 44

7 Ltent infections (%) Ltent infections (%) Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 Incidence disese for different ges of leves The min effects of ge were highly significnt (P <.5), nd the mens of mesurements repets long 6 yers differ significntly. For ech cv. young leves showed the highest infection, ut oldest hd significntly fewer lef lesions (figure 6, 7). The effect of lef ge on the rte of infected leves ws highly significnt. Oldest leves presented the lowest ltent infections percentge which reduced y 7.3% for Chetoui cv. And 45% for Meski cv. This increse of degree of susceptiility of the olive tree to OLS disese with decrese of lef ge might e due to the cuticle thickness c Oldest leves Meski Lst yer leves Meski Current yer leves Meski Figure 6. Effects of ge of leves from Meski cv. on percentge of ltent infections of the lef spot disese. 14 Lef ge Oldest leves Chetoui Lst yer leves Chetoui Current yer leves Chetoui Lef ge Figure 7. Effects of ge of leves from Chetoui cv. on percentge of ltent infections of the lef spot disese. Progressive Acdemic Pulishing, UK Pge 45

8 Ltent infections (%) Ltent infections (%) Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 Incidence disese for different directions The efficcy of the different directions vried ws shown in fig 5. At ll trees, the leves sumitted to the north direction were the most ffected y lef spot disese with the men of ltent infection percentges rnging from 16 to 67% for Meski cv. Ltent infections for Meski cv. ws pproximtely reduced y 5% on trees tht exposed to south nd estern directions, compred with out 6% ltent infections for those of Chetoui cv. in the sme directions (Figure 8, 9) Meski Est Meski West Meski North Meski South Figure 8. Effects of direction on percentge of ltent infections of the lef spot disese on Meski cv. 14 Direction Chetoui Est Chetoui West Chetoui North Chetoui South Direction Figure 9. Effects of direction on percentge of ltent infections of the lef spot disese on Chetoui cv. Progressive Acdemic Pulishing, UK Pge 46

9 Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 Fungl development Oservtions on slides contining Fusicldium olegineum showed conidi germintion on fllen leves until 12 dys in spring time, fter tht conidi development ws stopped in culture medi. Studies crried out on different cultivrs nd in vrious sesons showed tht no sexul form ws oserved on infected leves or in culture medi. DISCUSSION Our studies were crried out on two olive cultivrs in the north west of Tunisi in order to survey the effects of some iotic nd iotic fctors on their resistnce to olive lef spot disese. The olive lef spot disese, cused y the fungus Fusicldium olegineum is the disese most common olive in mny countries, cusing severe defolition tht weken progressively the tree nd cuse crop losses estimted t more thn 6%, lthough in some yers nd plces cn e ctstrophic. Most infected leves nd fruit fll to the ground. Olive oil otined from fllen fruit is of poor qulity ecuse vrious sprophytic fungi colonize the fruit nd chnge the cidity nd orgnoleptic chrcteristics of the oil (Andrés, 1991). Although symptoms my vry depending on the vriety olive, ge nd conditions of the lesion environment in which they develop, usully re esily identified (Trpero nd Blnco, 1999). It is known tht climtic conditions influence the development of the olive lef spot. The disese is very grve in humid res nd cuses very significnt yield losses (Wilson et Ogw, 1979). The fruit rot cused y Spiloce olegin ws oserved in the humid zones, cse of Clri region (Southern Itly) chrcterized y environmentl conditions fvoring the development of the epidemic (Grniti,1993) depends on other fctors: cultivr types, density nd ge of plnttions (Agostino, 27 ; Grniti, 1993 ; De Mrzo et l., 1993; Lviol et Scrito,,1993; Mcdonld et l., 2). Ltent infections of disese were mesured in spring nd utumn sesons, the min periods of development of lef spot in Tunisi. López-Doncel et l. (1994, 1998, nd 1999) hs used the sme method in lortory to evlute the resistnce olive cultivrs to olive lef spot disese nd to determine the influence of fctors environmentl nd host the infection nd lef spot disese development (Virueg nd Trpero, 1999). Our results showed tht Meski is susceptile thn Chetoui to this disese. Mny studies showed tht Meski cultivr is the most susceptile nd Chetoui is less susceptile ut Picholine vriety is more resistnt to OLS (Triki et l., 23). Mesurements crried on the lef ge, height nd direction of trees on two olive cultivrs Meski nd Chetoui showed difference etween vrieties. The reltive humidity effects were significntly different for the cultivrs on the disese incidence. Wether conditions nd the presence of developing leves during erly spring re usully dequte for lef infection in olive growing res in southern Spin (Virueg et l, 211; Onor et l, 211; Roul et l, 212). Studies conducted on olive inoculted with S. olegin hve reveled tht the severity of infections is correlted liner nd negtively with ge leves, eing very young leves extremely susceptile. Becuse the mture olive leves hve importnt resistnce to infection Progressive Acdemic Pulishing, UK Pge 47

10 Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 y S. olegin, the min infection periods occur during the lef growth (Onor et l, 211; Virueg et l, 211). These results re consistent with those of Lόpez-Doncel et l. (2) who found tht younger leves were more susceptile to olive lef spot thn older leves. The otined results definitely clrify the controversy existing etween uthors ssigned incresed susceptiility to the old leves (Andreucci nd Bonifcio, 1962; Petri, 1913; Prot, 1958; Wilson nd Miller, 1949) nd those who thought otherwise (D'Armini nd Rggi, 1966; Lvee, 199; Tenerini, 1964), sed minly on oservtions country. Typiclly, disese severity on the youngest leves ws out three to five times higher thn the oldest leves, nd there ws more rpid increse in the severity etween 6 nd 24 h of wetness for the youngest leves thn for the other two lef ges (Onor, 211). McHrdy (1996) reported tht the decrese of olive sc severity with incresing lef ge is cse of resistnce, or ge-relted resistnce, which hs een reported for mny plnt diseses including pple sc. The pthosystems hs een ssocited with vrious physicl nd chemicl fetures of the lef cuticle in Cliforni (Miller, 1949; Grniti, 1993; Guechi nd Girre, 1994). The differences could lso e ssocited with the wter-repellent wxes tht re uilt up on lef surfces s they ge. The wxes prevent formtion of wter films in which pthogens might germinte (Agrios, 1997). In ddition, the thicker cuticle of older leves cn etter impede penetrtion thn in young leves (Jeyrmrj et l., 25), n importnt fctor for S. olegin which infects y direct cuticle penetrtion (Grniti, 1993). The results of this study showed tht the leves exposed to north nd west directions presented more lesions on upper surfce of Meski vriety nd then were more susceptile to the OLS then those in the estern nd south fronts. In Morocco, Besri nd Outssourt (1984) hve worked on the olive lef spot distriution on two fces (North nd South) of the some trees cnopy in two olive-growing regions: Béni Melll nd Mrrkech. Both uthors noted tht the percentge of leves infection exposed to North is significntly higher thn leves exposed to South. Tjnri (1999) lso studied the disese distriution in the region o f Kel Srghn in Morocco. He noted tht the exposed fce of the olive tree in the North is the most contested, followed y the West, South nd Est. The interior of the cnopy is more ttcked thn the outside nd the ottom of the cnopy is more infested thn the top. For The height of tree influences, otined results showed tht percentge of ltent infections decreses with incresing distnce from the lnd. Grniti (1993) indicted tht environmentl fctors such s temperture nd humidity re the driving forces of infection nd spred of the disese. The dispersl distnce nd its response to wether conditions hve not een reported for olive sc s it hs een for the scosporic phse of similr pthogens, such s Venturi inequlis nd V. pirin (Aylor, 1995). Conidil germintion occurs during cold nd riny wether (Tjnri, 1999). The excess of free wter increses the humidity in the folige of the olive trees; the lef surfce ecomes wet which promotes the dissemintion, contmintion nd germintion of conidi1 (Lviol et Scrito, 1993). In the sence of rin nd when the humidity is ove 7%, there is dispersion of conidi y wind which ffect severity of the olive lef spots (Tjnri, 1999; Besri et Outssout, 1984). Progressive Acdemic Pulishing, UK Pge 48

11 Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 The conidi germintion ws stopped fter less thn week. These results re in concordnce with those otined y Vrueg nd Trpero (1999) which reported tht the conidi formed in leves on fllen leves cn survive for severl months; lthough once they hve seprted from the conidiophores they lose their germintion ility in less thn week. Sexul fruiting odies of S. olegin were not oserved in this study or found in previous reserch done in Cliforni (Miller, 1949; Grniti, 1993; Guechi nd Girre, 1994). According to other uthors, however, the most importnt inoculum sources re infected leves tht hve fllen to the soil surfce (Asswh, 1967; Guechi nd Girre, 1994; Lviol, 1968). Under humid conditions, the pthogen could not e detected on fllen leves fter 3 months ecuse the leves were colonized y sprophytic fungi (Virueg et l., 211). CONCLUSIONS Finlly, our study demonstrted tht in North West of Tunisi, utumn nd spring survey of development of OLS on Meski nd Chetoui cultivrs in the similr field conditions, indicted tht there re correltion etween some prmeters like cultivr, lef ge, height of tree, direction of leves nd reltive humidity nd the severity disese of lef spot. REFERENCES Al-Khti, M., Alhussen, K., El-Bnn, N., & Zydeh, M. (2) Biologicl control of olive lef spot (pecock spot disese) cused y Cycloconium oleginum (Spiloce olegine). Journl of Microiology nd Antimicroils, 6, Alonso, R., Besor, J. nd Perdices, M. (26) Efficci del product lnzder core (Agrométodos, S.A.) contr el repilo en plntones de olivo inoculdos rtificilmente con Spiloce olegin. In, Fruticultur profesionl, 16, 1-4. Agostino T., Tomesi S., Milgros S., Fernndez-escor, R., Riccrdo, A., Antonell, L., et Jrdk, T. (27) Techniques de production en oléiculture. 34 pp. Agrios G.N. (25) Plnt Pthology. Fifth Ed. Elsevier Acdemic Press, 984 p. Andrés, F. De. (1991) Enfermeddes y plgs del olivo. 2 ed. Riquelme y Vrgs Ediciones, Jén, Spin. Andreucci, E. Y. nd Bonifcio, A. (1962) Richerche su Cycloconium oleginum in lcune zone deli Toscn Settentrionle. Phytopthol. Medit., 1, Asswh, M. W. (1967) Cycloconium lef spot of olive in Egypt. Phytopthol. Mediterr., 6, Aylor, D. E. (1995) Verticl vrition of eril concentrtion of Venturi inequlis scospores in pple orchrd. Phytopthology, 85, Azeri, T. (1993) Reserch on olive lef spot, olive knot nd Verticillium wilt of olive in Turkey. EPPO Bull., 23, Besri M. et Outssout (1984) Influence de l'exposition de l frondison de l'rre sur l mnifesttion de Cycloconium oleginum Cst., gent de l mldie de l'oeil de pon de l'olivier. Olive, 3, De Mrzo L., Frisullo S., Lops F. nd Rossi V. (1993) Possile dissemintion of Spiloceolegin conidi y insects (Ectopsocus riggsi). Bull. OEPP/EPPO Bull., 23, D Armini, M. nd Rggi, V. (1966) Alcuni crtteri morfologici e fisiologici di cultivrs d olivo in relzione ll loro divers resistenz Spiloce olegin (Cst) Hugh. Phytopthol. Med., 5, FAOSTAT (214) http,//fostt3.fo.org/downlod/q/qc/e Grniti, A. (1993) Olive sc, Review. EPPO Bull., 23, Progressive Acdemic Pulishing, UK Pge 49

12 Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 Grniti, A. Lviol, C. (1968) Epidemiology of Spiloce olegin on olive in Itly. First Interntionl Congress of Plnt Pthology (Astrcts Ppers), London, pp. 68. Guechi, A., nd Girre, L. (1994) Sources of Cycloconium oleginum (Cst.) conidi for infection of olive leves nd conditions determining lef spot disese development in the region of Sétif, Algeri. Mycopthologi, 125, Hudson, H. J. (1971) The development of the sprophytic fungl flor s leves senesce nd fll. Pges in, Ecology of Lef Surfce Microorgnisms. T. F. Preece nd C. H. Dickinson, eds. Acdemic Press, London. Jyrmrj, P.R., Pius, P.K., Mnin, S., Nithy Meenkshi, S. (25) Certin Fctors ssocited with Blister light resistnce in Cmelli sinensis (L.) O. Kuntze. Physiol. mol. PlntPthol., 67, Lvee, S. (199) Aims, methods, nd dvnces in reeding of new olive (Ole europe L.) cultivre. Act Hort., 286, Lviol, C. (1966) Contriution to the knowledge of the iology of Spiloce olegin (Cst.) Hugh, in Apuli. Proc. First Congr. Medit. Phytopth. Union, Bri. pp Lviol, C. (1968) Aspetti iologici ed epifitologici di Spiloce olegin (Cst.) Hugh, in Itli. Ann. Fc. Agrri Univ. Bri, 22, Lviol C. nd Scrito G. (1993) Oservtions on spore production in Spiloce olegin in southern Itly. Bull. OEPP/EPPO Bull., 23, López-Doncel, L. M; Virueg, J. R. nd Trpero, A. (1994) Respuest del olivo l inoculción con Spiloce olegin. VII Congreso de l Sociedd Esp- ñol de Fitoptologí, Sitges. pp. 48. López-Doncel, L. M.; Grcí-Berenguer, A. nd Trpero, A. (1998) Resistenci del olivo l Repilo cusdo por Spiloce olegin. IX Congreso de l Sociedd Espñol de Fitoptologí, Slmnc, pp López-Doncel, L. M.; Grcí-Berenguer, A. nd Trpero, A. (1999) Resistnce of olive tree cultivrs to lef spot cused y Spiloce olegin. Act Hort., 474, López-Doncel, L. M., Virueg-Puente, J. R., & Trpero-Css, A. (2) Respuest del olivo l inoculcion con Spiloce olegin, gente del repilo. Boletin de Snidd Vegetle Plgs, 26, Mcdonld, D., Crtree J.R., Wiesinger G., Dx T., Stmou N., Fleury P., Gutierrez-Lzpit J. et Gion A. (2) Agriculturl ndonment in mountinres of Europe, environmentl consequences nd policy responses. Journl of Environmentl Mngement, 59, Mchrdy, W. E. (1996) Apple sc, iology, epidemiology, nd mngement. APS Press, St. Pul, Minnesot. 545 pp. Miller, H.N. (1949) Development of the lef spot fungus in the olive lef. Phytopthology, 39, Onor, F.O., Wlter, M., Jones, E.E. nd Jspers, M.V. (28) Effect of temperture, reltive humidity, lef witness nd lef ge on Spiloce olegin conidium germintion on olive leves. Europen Journl of Plnt Pthology, 12, Onor, F. O., Wlter, M., Jones, E. E., nd Jspers, M. V. (211) Effects of temperture, inoculum concentrtion, lef ge, nd continuous nd interrupted wetness on infection of olive plnts y Spiloce olegin. Plnt Pthol., 6, Petri, L. (1913) Studi sulle mlttie del Polivo. Mem. R. Stz. Ptol. Veg., Rom. 16 pp. Prot, U. (1958) Contriuti li ptologi dell'olivo coltivto in Srdegn. Studi Sssresi, 6, Roul, C., Regis, S., nd Nicot, P. C. (212) Field models for the prediction of lef infection Progressive Acdemic Pulishing, UK Pge 5

13 Europen Journl of Advnced Reserch in Biologicl nd Life Sciences Vol. 4 No. 1, 216 nd ltent period of Fusicldium olegineum on olive sed on rin, temperture nd reltive humidity. Plnt Pthol. Online puliction. doi,.1111/j x SAS Institute. (1985) Softwre SAS System. SAS institute Inc. Tenerini, I. (1964) Richerche sull iologi ed epidemiologi deli Spiloce olegine (Cst.) Hugh., gente dell'occhio di pvone dell'olivo. Phytopthol. Medit., 3, Tenerini, I. nd Loprieno, N. (196) Ricerche istologiche sulle zone di insedimento del Cycloconium oleginum Cst., gente dell'occhio di pvone dell'olivo. Phytopthologische Zeitschriff, 39, Tjnri, H. (1999) L mldie de l œil de Pon. L Assocition Mrocine de Protection des plntes. Journée ntionle sur l protection phytosnitire de l olivier, Mrrkech, 27 mi 1999, Trpero, A.; Luque, F. nd Segur, R. (1994) Efecto de l tempertur y l humedd sore l germinción de conidis de Spiloce olegin, gente del repilo del olivo. VII Congreso de l Sociedd Espñol de Fitoptologí, Sitges, Brcelon, 56 pp. Trpero, A., nd Roc, L. F. (24) Bses epidemiológics pr el control integrdo de los Repilos del olivo. Phytom Espñ, 164, Triki, M.A.; Ftm, F. nd Hmdi, W. (23) Mldie de l œil de pon de l olivier en Tunisie, ioécologie et mesures de lutte. http,// Virueg, J.R. nd Trpero, A. (1999) Epidemiology of lef spot of olive tree cused y Spiloce olegin in southern Spin. Act Hort., 474, Virueg, J. R.; Trpero, A. nd Moreno, S. (1999) Eficci del Kresoxim-metil sore Spiloce olegin, gente del Repilo del olivo. IX Simposium Científico Técnico Expoliv, Jén. Virueg, J. R., Roc, L.., Morl, J., nd Trpero, A. (211) Fctors ffecting infection nd disese development on olive leves inoculted with Fusicldium olegineum. Plnt Dis., 95, Wheeler, B. E. J. (1969) An introduction to plnt diseses. John Wiley & Sons, London. 374 pp. Wilson E.E. nd Miller, H.N. (1949) Olive lef spot nd its control with fungicides. Hilgrdi, 19, Wilson, E.E. Ogw, J.M. (1979) Fungl, cteril nd certin non-prsitic diseses of fruit nd nut crops in Cliforni. Clifornin Agriculturl Science Pulictions, Berkeley, Cliforni, USA. Zrco, A., Virueg, J. R., Roc, L. F., nd Trpero, A. (27) Detección de ls infecciones ltentes de Spiloce olegin en hojs de olivo. Bol. Sn. Veg. Plgs, 33, Progressive Acdemic Pulishing, UK Pge 51