Pathogen. Bakiteriya wa blackleg nthawi zambiri amakhala ndi mbewu. Zida zogwirira ntchito zoipitsidwa monga zodulira mbewu ndi obzala mbewu zimathandizira kufalikira kwa bakiteriya ku ma tubers athanzi. Mvula yowombedwa ndi mphepo ikhoza kukhala gwero la inoculum.
Kukula kwa matenda. Ngati kasupe ndi konyowa komanso kozizira, mbewu zomwe zili ndi kachilomboka komanso zinamera zimawola zisaname kapena zikamera, zomwe zimapangitsa kuti pakhale malo osagwirizana. Ngati nyengo ya masika imakonda kumera mwachangu, mbewu yomwe ili ndi kachilombo imatulutsa mbewu zofooka zokhala ndi tsinde zowonetsa kuwola kwakuda kochokera pambewu yomwe ili ndi kachilomboka.
M'nyengo yotentha, mabakiteriya ochokera ku tizidutswa ta mbewu ndi tsinde zowola amafalitsidwa ndi madzi m'nthaka ndipo amawononga ma tubers atsopano. Mvula yowomba ndi mphepo imafalitsa mabakiteriya ku zomera zathanzi.
Matendawa amatha kufalikira m'malo osungira, makamaka atakolola konyowa. Mitundu ina, monga Monona ndi Chieftain, imakhudzidwa kwambiri ndi blackleg.
Zizindikiro. Zizindikiro za blackleg zimatha kukula nthawi iliyonse panyengo. Machubu atsopano omwe ali ndi kachilomboka amakhala ndi zotupa zomwe zimayambira kumapeto kwa tsinde.
M'kupita kwa nthawi, zowola zimasanduka mdima. Pakapita patsogolo, minofu yomwe ili ndi kachilomboka imasanduka imvi-yakuda komanso yakuda.Zoyambira zimawonetsa kuvunda kwakuda komwe kumayambira pambewu. Kuwola kumapitilira mtunda wosiyanasiyana kupita ku tsinde, kulikonse kuyambira ma centimita angapo mpaka pamwamba pa tsinde.Chomera chodwala ndi zowola zomwe zimachokera ku njere kupita ku tsinde. Nthawi zambiri, minofu yomwe ili ndi kachilomboka imalowetsedwa ndi mabakiteriya achiwiri omwe amatulutsa fungo la nsomba.Zomera zomwe zili ndi kachilombo zimapunthwa ndikuwoneka zowuma komanso zowongoka, makamaka kumayambiriro kwa nyengo. Masamba amakhala chlorotic, ndipo timapepala tating'onoting'ono timakwera m'mphepete.Chomera chakale chokhala ndi masamba okulungidwa m'mwamba chifukwa cha matenda a m'miyendo yakuda.Mwendo wakuda kwambiri wapangitsa kuti tsinde lithyoke. M'nyengo yamvula, kuvunda kumakhala kofewa komanso kosalala. M'mikhalidwe yowuma, minofu yomwe ili ndi kachilombo imatha kuuma ndi kufota.Chomera chakale chinafota ndi kufa chifukwa cha mwendo wakuda.