Mary Hausbeck, Dipatimenti ya Zomera ndi Dothi ndi Microbial Sciences, Michigan State University-July 23, 2014
Boma la Michigan latsimikizira downy mildew pa anyezi.Ku Michigan, matendawa amapezeka zaka zitatu kapena zinayi zilizonse.Awa ndi matenda owopsa kwambiri chifukwa ngati salandira chithandizo, amatha kuchulukana mwachangu ndikufalikira kudera lonselo.
Downy mildew amayamba chifukwa cha kuwonongeka kwa tizilombo toyambitsa matenda Peronospora, zomwe zimatha kufooketsa mbewu nthawi isanakwane.Zimayamba kuwononga masamba oyambilira ndipo zimawonekera m'mawa wanthawi yopuma.Itha kukula ngati imvi-wofiirira wofiirira wokhala ndi mawanga opyapyala.Masamba omwe ali ndi kachilomboka amakhala obiriwira obiriwira kenako achikasu, ndipo amatha kupindika ndi kupindika.Chotupacho chikhoza kukhala chofiirira-chofiirira.Masamba okhudzidwa amasanduka obiriwira obiriwira poyamba, kenako achikasu, ndipo amatha kupindika ndi kugwa.Zizindikiro za matendawa zimadziwika bwino pamene mame akuwoneka m'mawa.
Kufa msanga kwa masamba a anyezi kudzachepetsa kukula kwa babu.Matenda amatha kuchitika mwadongosolo, ndipo mababu osungidwa amakhala ofewa, okwinya, amadzi ndi amber.Mababu asymptomatic amamera msanga ndikupanga masamba obiriwira owala.Babuyo imatha kutenga kachilomboka ndi mabakiteriya achiwiri, omwe amawola.
Tizilombo toyambitsa matenda a Downy mildew timayamba kulowa m'malo ozizira, pansi pa madigiri 72 Fahrenheit, komanso m'malo achinyezi.Pakhoza kukhala maulendo angapo a matenda mu nyengo imodzi.Spores amapangidwa usiku ndipo amatha kuwomba mtunda wautali mumlengalenga wonyowa.Pamene kutentha kuli 50 mpaka 54 F, amatha kumera pa minofu ya anyezi mu maola awiri ndi theka mpaka asanu ndi awiri.Kutentha kwakukulu masana ndi chinyezi chaching'ono kapena chapakatikati usiku zimalepheretsa kupangika kwa spore.
Ma spores a overwintering, otchedwa oospores, amatha kupanga mu minyewa yakufa ndipo amapezeka mu anyezi odzipereka, mulu wodula anyezi, ndi mababu osungidwa omwe ali ndi kachilombo.Ma spores ali ndi makoma okhuthala komanso chakudya chokhazikika, kotero amatha kupirira kutentha kwanyengo yachisanu ndikukhala m'nthaka kwa zaka zisanu.
Purpura imayamba chifukwa cha bowa Alternaria alternata, matenda wamba a masamba a anyezi ku Michigan.Imawonekera koyamba ngati kachilonda kakang'ono konyowa m'madzi ndipo imakula mwachangu kukhala malo oyera.Tikamakalamba, chotupacho chimasanduka bulauni kukhala wofiirira, wozunguliridwa ndi madera achikasu.Zotupazo zidzalumikizana, kulimbitsa masamba, ndikupangitsa kuti nsonga ibwerere.Nthawi zina babu wa babu amadwala kudzera pakhosi kapena pachilonda.
Pansi pa chinyontho chochepa komanso chapamwamba, spores mu chotupa amatha kupanga mobwerezabwereza.Ngati pali madzi aulere, ma spores amatha kumera mkati mwa mphindi 45-60 pa 82-97 F. Spores imatha kupanga pakatha maola 15 pomwe chinyezi chachifupi chimakhala chachikulu kuposa kapena chofanana ndi 90%, ndipo chimatha kufalikira ndi mphepo, mvula, komanso ulimi wothirira.Kutentha ndi 43-93 F, ndipo kutentha kwakukulu ndi 77 F, zomwe zimathandizira kukula kwa bowa.Masamba akale ndi ang'onoang'ono owonongeka ndi ma thrips a anyezi amatha kutenga matenda.
Zizindikiro zidzawoneka tsiku limodzi kapena anayi pambuyo pa matenda, ndipo spores zatsopano zidzawonekera pa tsiku lachisanu.Madontho ofiirira amatha kufooketsa mbewu za anyezi nthawi yake isanakwane, kusokoneza mtundu wa babu, ndipo zitha kuola chifukwa cha tizilombo toyambitsa matenda.Tizilombo tofiirira tating'onoting'ono timatha kukhalabe m'nyengo yozizira pa ulusi wa fungal (mycelium) mu zidutswa za anyezi.
Posankha mankhwala ophera tizilombo, chonde sinthani zinthu zomwe zili ndi mitundu yosiyanasiyana yochitira (FRAC code).Gome lotsatirali likutchula zinthu zolembedwa za downy mildew ndi mawanga ofiirira pa anyezi ku Michigan.Bungwe la Michigan State University likuti kumbukirani kuti zilembo za mankhwala ophera tizilombo ndi zikalata zamalamulo zokhudzana ndi kugwiritsa ntchito mankhwala ophera tizilombo.Werengani malembawo, pamene akusintha pafupipafupi, ndipo tsatirani malangizo onse ndendende.
*Mkuwa: baji SC, ngwazi yamalonda, kuchuluka kwa mkuwa kwa N, mankhwala a Kocide, Nu-Cop 3L, Cuprofix hyperdispersant
*Sizinthu zonsezi zomwe zimayikidwa ndi downy mildew ndi mawanga ofiirira;DM imalimbikitsidwa makamaka polimbana ndi downy mildew, PB imalimbikitsidwa makamaka poletsa mawanga ofiirira