PEST MANAGEMENT DECISION GUIDE: GREEN LIST Dry rot of yam bradys Yam Prevention Monitoring Direct Control

l Use of clean, nematode-free planting material: l Monitor for symptoms: l After harvest, all undersized and l Before planting, inspect carefully each planting piece for dry rot symptoms by l The feeding of the rotten tubers should be collected and scraping away the skin produces cavities buried deeply or burnt. l Use hot water treatment to reduce or eliminate nematodes from tubers (water l The cavities become darker as the rot temperature of 50-55°C for up to 40 min) progresses (normally less than 2 cm) Damage by the nematode l Seed tubers showing symptoms of dry rot (cracking and flaking) should not be l Externally, cracks appear in the skin, Scutellonema bradys on white used for planting which becomes crinkly, and parts yam tubers (IITA, Flickr) l Coating the setts in wood ash may help to reduce nematode numbers flake off revealing the dark rot beneath l Some crops should be avoided prior to planting yams or as yam intercrops, i.e. , , green gram, , kenaf, okra, and melon. l Rots continue in storage and can lead Preference should be given to maize, groundnut, chilli, indian spinach or to complete decay of the tuber as sorghum other rot-causing organisms take over l Add cow dung into the mound to reduce nematode populations (as do l Extensive rots can develop without applications of NPK fertilizer and phosphorus alone, but nitrogen alone cracking and flaking of the skin, and increases populations) are only seen when the skin is Dry rot beneath the skin of scraped away white yam tubers (IITA, Flickr) l Use legume cover crops as restorative fallows to reduce nematode populations (Aeschynomene histrix, Puerariaphas eoloides, Mucuna puriens and l Sometimes external symptoms are Centrosema spp.) not obvious on the tubers l Keep weeds to a minimum, especially those that are hosts of yam nematode, l There are no above ground e.g. Eupatorium, Synedrella and Chromolaena symptoms l Treat tubers after harvesting to prevent storage losses l Removal of crop debris reduces soil populations nematode

Note: Pesticides may be available to control this pest. Please check with the Ministry of Agriculture in your country to find out which pesticides are registered in your country and the local restrictions for their use.

CREATED/UPDATED: July 2016 LOSE LESS, FEED MORE PRODUCED BY: Plantwise Plantwise is a CABI-led global initiative www.plantwise.org