A searchable reference library of common African crop diseases and pests.
MLN (viral complex)
Mild mottling progressing to necrosis, leaf drying from margins, stunting, dead heart, poor or no ear formation.
Spodoptera frugiperda
Ragged holes in leaves, sawdust-like frass near whorl, damaged growing points. Larvae feed at night.
Ipomovirus (CBSV)
Yellow chlorosis on leaves, brown streaks on stems, brown necrotic rot in tuberous roots. No leaf distortion.
Colletotrichum spp.
Dark sunken lesions on fruits, black spots on leaves, dieback of twigs. Pinkish spore masses in wet conditions.
Phytophthora infestans
Water-soaked lesions on leaves, white fuzzy growth on undersides, brown spots on fruits. Spreads rapidly in wet conditions.
N deficiency
Yellowing (chlorosis) starting from lower leaves, stunted growth, poor tillering, small pale green leaves.
Ralstonia solanacearum
Sudden wilting of leaves, vascular discoloration, bacterial ooze from cut stems. Plants may recover at night initially.
Striga hermonthica
Stunted growth, yellowing, purple flowers emerging from soil. Attached to crop roots, causing wilting before emergence.
Aphis gossypii and others
Clusters of small soft-bodied insects on undersides of leaves and growing tips. Leaves curl, yellow, and distort. Sticky honeydew on leaves with black sooty mold. Stunted growth and reduced yields.
MLN disease complex
Chlorotic mottling on leaves, necrotic lesions, stunting, dead heart symptom, premature plant death. Leaves turn yellow with brown streaks. Plants may fail to produce cobs.
Water-soaked dark green to brown lesions on leaves, white fungal growth on underside of leaves in humid conditions. Lesions on stems are dark brown. Fruits develop firm brown patches. Can destroy crop within days.
Begomovirus
Yellow-green mosaic pattern on leaves, leaf distortion, stunting, reduced tuber size. Leaves appear twisted and distorted with pale green or yellow patches.
Bright green parasitic weed growing attached to crop roots. Wilting and yellowing of host plant, stunting, reduced yield. Purple or pink flowers appear above ground. Can cause total crop failure.
TYLCV (Begomovirus)
Upward curling of leaves, yellowing of leaf margins, stunting, flower drop, reduced fruit set. Leaves become small and cup-shaped. Plants take on a bushy, stunted appearance.
Ipomovirus
Brown streaks on stems, yellow/brown necrotic spots on leaves. Root necrosis - brown, dry rot in tubers making them inedible. Plants may appear healthy above ground but tubers are destroyed.
Dark sunken lesions on fruits and pods, black acervuli in lesions producing pink/orange spore masses. Leaf spots with grey centers and dark borders. Cankers on stems. Post-harvest rot on tubers.
Sudden wilting of plant during hot weather, leaves remain green but droop. White bacterial ooze from cut stems when placed in water. Plants may recover overnight but wilt again next day.
Windowpane damage on leaves, ragged feeding holes, sawdust-like frass in whorl, young larvae feed in whorls creating characteristic windowing effect. Heavy infestation can defoliate entire plants.