PEST MANAGEMENT DECISION GUIDE: GREEN AND YELLOW LIST Bacterial wilt disease in Irish potato Ralstonia solanacearum Prevention Monitoring Direct Control Direct Control Restrictions

l Select clean and healthy seed-tubers and l Bacterial wilt is a serious l Pull out plants with roots and l Prevention is the most powerful and often only planting material. Any tuber that is disease that appears at all surrounding soil and dispose measure (see first column).; Chemical sprays are blackish, soft or oozes should not be used. stages of potatoes. of far away by burning or of little or no help because this disease is l Seed tuber quarantine: Do not use tubers l Regularly visit the field to burying deeply (at least 1 survives in the soil. Chemicals for soil treatments from infected regions (get this information search for the occurrence of metre).. Transport infected are very dangerous to you and to the Leaves across entire plant from zonal agricultural extension offices). the disease. material in a plastic bag to environment. Moreover, most of them are not show wilty patches at the tip avoid spreading the disease. allowed or will not be effective in controlling the (photo: Agricultural scientific l Sprout tubers in a dark cool place before l Early symptoms include wilty disease. collections 1983) planting to speed up growth and reduce patches at the tips of leaves l Do not re-plant potatoes in the same spot. exposure to diseases. throughout the entire plant l Farmers are not allowed to buy and use WHO l Avoid furrow and flood irrigation because l Recognise bacterial wilt l In case of bacterial wilt toxicity class Ia, Ib, II products without special this bacteria can also survive in the soil disease through sudden wilt of outbreak, stop potato permits (Plant Protection Act Tanzania) and can be spread by water (if furrow whole plants (not slow wilt or growing for 5 seasons and irrigation is needed then flow water from partial wilt as other diseases) plant non-solanaceous crops l Antibiotics and soil fumigants are not allowed to new to old fields to minimise spread of scattered across the otherwise like cereals, beans, be used by farmers in crop production (Plant diseases in the field). healthy-looking field. sugarcane, cabbage, okra, Protection Act of Tanzania) maize, cowpea (but not with Potato plants have wilted and l Rogue out volunteer potatoes immediately l When first damage symptoms pepper, Irish tomato, l Always consult recent list of registered pesticides leaves have become brown after harvest. appear on young plants (photo: Mauritius Sugar tobacco, eggplants, and (MAFC / TPRI). Industry Research Institute) l No resistant varieties yet in Tanzania consider immediate direct nightshade). control action l When using a pesticide, always wear protective clothing and follow the instructions on the product label.

Black spots and sliced tubers with white bacterial ooze (photo: Shoura chemicals)

Tanzania CREATED/UPDATED: September 2013 AUTHOR(S): Jackson Sadiiki (Plant doctor, Lushoto district) Nuran Y. Mohamed (Plant doctors, Meru district), Eva Aiwinia Uiso (TOSCI), Jubilant Mwangi (MAFC Tanzania) EDITED BY: Plantwise

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