Striga Witchweed in Maize Striga Asiatica Nakanyama in Nkoya Language Prevention Monitoring Direct Control Direct Control Restrictions

PEST MANAGEMENT DECISION GUIDE: GREEN AND YELLOW LIST Striga witchweed in maize Striga asiatica Nakanyama in Nkoya language Prevention Monitoring Direct Control Direct Control Restrictions

l Plant certified seeds, because all grains used for l Striga is prevalent in areas with low soil l Hand-pull Striga l Pre-emergence herbicides are difficult to sowing should be free of weed seeds. fertility and poor rainfall, such as Luangwa 2 - 3 weeks after apply as it is unsure when and where Striga l Use maize varieties that are tolerant to the seed Valley, parts of Southern Province and it begins to germinates. coating herbicide imazapyr, which will kill Striga. Western Province of Zambia. flower and never l Post-emergence herbicides are too late, Striga weed with orange –pink When using the herbicide in seed dressing, refer l Plant trap crops such as napier grass or allow it to mature flowers attacking maize (Photo to yellow list Desmodium early to detect the presence to produce hence should not be considered by: Research into use, Kenya) of the weed. as it will emerge there first seeds . This is l Use phosphorus fertilizer like compound D or l When using a pesticide, always wear before attacking maize. Few napier grass for future control super phosphate. This is because phosphorous protective clothing. Follow the instructions or Desmodium should be planted in of the weed as boosts the plant to fight Striga. on the product label, such as dosage, selected areas at random in the field. the damage to l Intercrop maize with Desmodium in alternate the maize plant timing of application, pre-harvest interval, rows. Desmodium stimulates the germination of l Check for orange-pink flowered ca. 5 to 30 is already done max number of sprays, restricted re-entry Striga but is not affected. Emerging Desmodium cm high Striga growing in close contact when Striga has interval. Do not empty into drains. can then be fed to cattle. with maize 2-3 weeks after maize emerged emergence. The damage is there already, l WHO class II pesticides might not be l Once Striga has germinated in the field, it is too but it helps to plan control options for the allowed in local IPM schemes. late to protect the crop, but Striga should be still future. uprooted before it sets seeds. This is for l Always consult recent list of registered prevention of future Striga growth. l Check for stunting and twisting of maize, as a symptom of Striga. pesticides (ZEMA). Striga causing stunting (Photo l Avoid grazing of animals in Striga - infested by: Hakizamungu Leon) fields. l Check for signs of phosphorus deficiency l Imazapyr –based l WHO toxicity class such as purplish discolouration of maize products (ARSENAL U: unlikely l Rotate with groundnuts, soya beans or other leaves. This may be a sign of Striga legumes for minimum 3 yrs to control Striga. or others) as hazardous when causing phosphorus deficiency before it herbicide that can used according to l Note that one measure alone is not effective emerges from the ground. be used in seed instructions. enough against Striga. dressing Contact agro- preventively. dealers for details Belongs to of dressings. Imadazolinone group of herbicide.

Zambia CREATED/UPDATED: July 2014 AUTHOR(S): Brian Chisunka (SCCI, MAL), Tel.: +260 975016988, email: [email protected], Matthews Matimelo (ZARI), Henry Mgomba (MAL) EDITED BY: Plantwise LOSE LESS, FEED MORE Plantwise is a CABI-led global initiative www.plantwise.org