UMary Hausbeck, iSebe leZityalo kunye neNzululwazi yeMicrobial, iYunivesithi yaseMichigan State-Julayi 23, 2014
Ilizwe laseMichigan liqinisekisile i-downy mildew kwitswele.EMichigan, esi sifo senzeka rhoqo kwiminyaka emithathu ukuya kwemine.Esi sisifo esiyingozi kakhulu kuba ukuba asinyangwa, sinokuphindaphindeka ngokukhawuleza kwaye sisasazeke kuwo wonke ummandla okhulayo.
I-Downy mildew ibangelwa kukutshatyalaliswa kwentsholongwane ye-Peronospora, enokutshabalalisa izityalo ngaphambi kwexesha.Iqala yosulela amagqabi angaphambili kwaye ibonakale ngentseni yexesha elingekhoyo.Ingakhula njengokukhula okungwevu-mfusa okufuzileyo kunye namachokoza abhityileyo.Amagqabi awosulelekileyo ajika abe luhlaza ngokukhanyayo aze abe tyheli, kwaye angagotywa aphinde asongwe.Isilonda sisenokuba mfusa-mfusa.Amagqabi achaphazelekayo ajika aluhlaza okhanyayo kuqala, emva koko atyheli, kwaye angasonga kwaye adilike.Iimpawu zesi sifo zibonwa kakuhle xa kuvela amazolo ekuseni.
Ukufa kwangoko kwamagqabi etswele kuya kunciphisa ubukhulu bebhalbhu.Usulelo lunokwenzeka ngokwenkqubo, kwaye iiglowubhu ezigciniweyo zithambile, zishwabene, zibe namanzi kunye ne-amber.Iibhalbhu ze-Asymptomatic ziya kuntshula ngaphambi kwexesha kwaye zenze amagqabi aluhlaza okhanyayo.Ibhalbhu inokosulelwa ziintsholongwane zesibini zebhaktiriya, ezibangela ukubola.
Iintsholongwane ze-Downy mildew ziqala ukosulela kumaqondo obushushu apholileyo, ngaphantsi kwe-72 degrees Fahrenheit, nakwiindawo ezifumileyo.Kusenokubakho imijikelo yosulelo oluninzi kwixesha lonyaka.I-spores iveliswa ebusuku kwaye inokuvuthela ngokulula umgama omde emoyeni omanzi.Xa ubushushu bungama-50 ukuya kuma-54 F, zinokuntshula kwithishu yetswele kwiyure enye enesiqingatha ukuya kwezisixhenxe.Ubushushu obuphezulu emini kunye nokufuma okufutshane okanye okwethutyana ebusuku kuya kuthintela ukumila kwembewu.
Izityalo ezikhula ngaphezu kwebusika, ezibizwa ngokuba zii-oospores, zinokubumba kwiithishu zezityalo ezifayo kwaye zinokufumaneka kumatswele amavolontiya, kwiimfumba zokusika itswele, kunye neebhalbhu ezigciniweyo ezisulelekileyo.Imbewu ineendonga ezingqindilili kunye nokutya okwakhelwe ngaphakathi, ukuze ikwazi ukumelana namaqondo obushushu angafanelekanga kwaye iphile emhlabeni ukuya kwiminyaka emihlanu.
I-Purpura ibangelwa yi-fungus Alternaria alternata, isifo esiqhelekileyo samagqabi e-anyanisi eMichigan.Iqala ukubonakalisa njengentsholongwane encinci yamanzi kwaye ikhula ngokukhawuleza ibe yindawo emhlophe.Njengoko sikhula, isilonda siya kuba mdaka sibe mfusa, sijikelezwe ziindawo ezityheli.Izilonda ziya kudibanisa, ziqinise amaqabunga, kwaye zibangele ukuba i-tip ihlehlise.Ngamanye amaxesha ibhalbhu yebhalbhu isuleleka entanyeni okanye enxebeni.
Ngaphantsi komjikelo womswakama ophantsi kunye ophezulu, i-spores kwi-lesion inokwakheka ngokuphindaphindiweyo.Ukuba kukho amanzi asimahla, iinkozo zinokuntshula kwisithuba semizuzu engama-45-60 kwi-82-97 F. Imbewu inokumila emva kweeyure eziyi-15 xa ukufuma okunxulumeneyo kungaphezulu okanye kulingane ne-90%, kwaye inokusasazeka ngumoya, imvula, kunye ukunkcenkceshela.Iqondo lobushushu yi 43-93 F, kwaye elona qondo lobushushu yi 77 F, nto leyo enceda ukukhula komngundo.Amagqabi amadala namancinci onakaliswe yithrips yetswele achaphazeleka lula kusulelo.
Iimpawu ziya kubonakala ngosuku ukuya kwezine emva kosulelo, kwaye amabala amatsha aya kuvela ngosuku lwesihlanu.Amabala amfusa anokutshabalalisa izityalo zetswele phambi kwexesha, wonakalise umgangatho webhalbhu, kwaye anokukhokelela ekuboleni okubangelwa ziintsholongwane zesibini zentsholongwane.Intsholongwane yamachokoza amfusa ingaphila ebusika phezu komtya wokungunda (mycelium) kumaqhekeza etswele.
Xa ukhetha i-biocide, nceda utshintshe phakathi kweemveliso ezineendlela ezahlukeneyo zesenzo (ikhowudi ye-FRAC).Le theyibhile ilandelayo idwelisa iimveliso ezinombhalo we-downy mildew kunye namabala amfusa kwitswele eMichigan.Ulwandiso lweYunivesithi yaseMichigan State luthi khumbula ukuba iilebhile zezitshabalalisi ngamaxwebhu asemthethweni malunga nokusetyenziswa kwezibulali-zinambuzane.Funda iilebhile, njengoko zitshintsha rhoqo, kwaye ulandele yonke imiyalelo ngokuchanekileyo.
*Ubhedu: ibheji yeSC, imveliso yeentshatsheli, ukubalwa kobhedu kweN, imveliso yeKocide, iNu-Cop 3L, iCuprofix hyperdispersant
*Ayizizo zonke ezi mveliso ziphawulwe ngokungunda kunye namabala amfusa;I-DM ikhuthazwa ngokukodwa ukulawula ukungunda, i-PB iyacetyiswa ngokukodwa ukulawula amabala amfusa