תפריט נגישות
ניגודיות עדינהניגודיות גבוהה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם תפריט נגישותניגודיות עדינהניגודיות גבוההמונוכרוםהדגשת קישוריםחסימת אנימציהפונט קריאסגוראיפוס הגדרות נגישותלהורדת מודול נגישות חינםContributors: Hadar Yitzhak, Raviv Michael
Several composts were prepared under controlled conditions from a mixture of separated cow manure (SCM) mixed with either orange peels (OP), wheat straw (WS), dried tomato plants (TP) or dried pepper plants (PP) that were removed from the greenhouses after the end of the season. The suppression ability of these composts was tested while serving as components of soil-less media for several vegetable crops using four different formae speciales of Fusarium oxysporum: melonis, basilici, radicis-lycopersici and radicis-cucumerinum (FOM, FOB, FORL and FORC respectively). TP-SCM, OP-SCM and WS-SCM significantly reduced disease development in melon, tomato and cucumber seedlings compared with the fast development of these diseases in conducive peat moss. Disease reduction ranging 41- 94% by the composts was evident using various types of inocula: conidia produced in culture, conidia naturally produced on infected stems and soil inoculum produced by enriching the soil with infected tissues. Pathogen colonization of the roots and stems of infected melon plants grown in TP-SCM and OP-SCM composts was significantly lower, compared to melon plants grown in peat. Sterilization of TP-SCM and OPSCM composts by gamma irradiation reduced the suppression ability of the composts, while disease development and final disease incidence in peat were not affected. The populations of the four Fusarium forma speciales declined in 60-100% during 35 days when their conidia were mixed with composts. This could stem from a direct effect on the pathogen. The suppression effect of TP-SCM compost was observed during four consecutive replanting cycles of melon seedlings inoculated with FOM and three growing seasons in a commercial cucumber greenhouse, naturally infested with FORC. TP-SCM and PP-SCM composts were also tested as suppressive media towards the pathogenic bacteria Clavibacter michiganensis sub sp. michiganensis (CMM) during two growing cycles of tomato transplants inoculated with CMM. The composts reduced CMM significantly (This is reported in this study for the first time). These data show the great potential of suppressing severe plant diseases by TP-SCM compost. Previous studies on suppression Fusarium diseases by composts have focused mainly on a single combination of compost and pathogen while in the current study all Fusarium pathogens (and in addition CMM and Botrytis) were suppressed by exposure to the same compost, indicating a relatively broad spectrum of target pathogens. The efficient suppression of FORC by TP-SCM compost along three growing seasons could not be explained only by a direct effect of the compost on the pathogen. FORC produces macroconidia which disperse in the air and can penetrate the plant through the foliage, without any contact with the growing medium. Therefore, we examined the possible involvement of induced resistance in this suppression phenomenon. Suppression of a foliar disease caused by Botrytis cinerea served as a tool for assessing the potential involvement of resistance induced by TP-SCM compost in melon and cucumber plants before studying the main target, FOM.
Contributors: Hadar Yitzhak, Raviv Michael
Several composts were prepared under controlled conditions from a mixture of separated cow manure (SCM) mixed with either orange peels (OP), wheat straw (WS), dried tomato plants (TP) or dried pepper plants (PP) that were removed from the greenhouses after the end of the season. The suppression ability of these composts was tested while serving as components of soil-less media for several vegetable crops using four different formae speciales of Fusarium oxysporum: melonis, basilici, radicis-lycopersici and radicis-cucumerinum (FOM, FOB, FORL and FORC respectively). TP-SCM, OP-SCM and WS-SCM significantly reduced disease development in melon, tomato and cucumber seedlings compared with the fast development of these diseases in conducive peat moss. Disease reduction ranging 41- 94% by the composts was evident using various types of inocula: conidia produced in culture, conidia naturally produced on infected stems and soil inoculum produced by enriching the soil with infected tissues. Pathogen colonization of the roots and stems of infected melon plants grown in TP-SCM and OP-SCM composts was significantly lower, compared to melon plants grown in peat. Sterilization of TP-SCM and OPSCM composts by gamma irradiation reduced the suppression ability of the composts, while disease development and final disease incidence in peat were not affected. The populations of the four Fusarium forma speciales declined in 60-100% during 35 days when their conidia were mixed with composts. This could stem from a direct effect on the pathogen. The suppression effect of TP-SCM compost was observed during four consecutive replanting cycles of melon seedlings inoculated with FOM and three growing seasons in a commercial cucumber greenhouse, naturally infested with FORC. TP-SCM and PP-SCM composts were also tested as suppressive media towards the pathogenic bacteria Clavibacter michiganensis sub sp. michiganensis (CMM) during two growing cycles of tomato transplants inoculated with CMM. The composts reduced CMM significantly (This is reported in this study for the first time). These data show the great potential of suppressing severe plant diseases by TP-SCM compost. Previous studies on suppression Fusarium diseases by composts have focused mainly on a single combination of compost and pathogen while in the current study all Fusarium pathogens (and in addition CMM and Botrytis) were suppressed by exposure to the same compost, indicating a relatively broad spectrum of target pathogens. The efficient suppression of FORC by TP-SCM compost along three growing seasons could not be explained only by a direct effect of the compost on the pathogen. FORC produces macroconidia which disperse in the air and can penetrate the plant through the foliage, without any contact with the growing medium. Therefore, we examined the possible involvement of induced resistance in this suppression phenomenon. Suppression of a foliar disease caused by Botrytis cinerea served as a tool for assessing the potential involvement of resistance induced by TP-SCM compost in melon and cucumber plants before studying the main target, FOM.
