Black pod

a small, hard, water-soaked spot appears on the pod — often near the tip, the stalk, or wherever rainwater collects — and quickly turns a chocolate-brown colour. Unlike a knock or a bruise, this spot does not stay put.

within a few days the brown patch darkens to black and races outward in a spreading half-moon shape until the whole pod turns black. A pod that looked healthy can be completely black in under a week — this speed is the hallmark of black pod.

in humid, wet weather a fine white or cream powdery bloom (the mould's spores) dusts the surface of the blackened pod. No other pod problem makes this white dust — it is your surest proof that it really is black pod.

split a black pod open and the beans are rotten — brown, slimy and stuck together — so the whole pod is a loss. The rot can also climb into the cushions and bark of the trunk, leaving dark, wet, sunken patches (called cankers — dead, rotting bark) that may ooze a reddish liquid.

cherelle wilt is a natural thinning where some small young pods blacken, then shrivel, dry hard and mummify on the tree — but they stay dry, with no white bloom, and the blackening does not spread to neighbouring pods. Black pod is a wet, spreading rot carrying the tell-tale white dust; cherelle wilt is a dry, harmless shrivel of just a few small pods.

black pod attacks the pods as they develop and ripen through the wet season — so this is when to watch closely. Start walking the plot once a week as soon as the rains set in, and step up your checks after long spells of rain and heavy, humid, still air, which is exactly when the disease races.

take a big W-shaped path across the plot so you pass through all four corners and the middle — not just the trees along the path by your house, where it is easy to keep looking at the same few.

at each stop, look over pods of every size, from the low pods near the wet ground to the ones high on the tree, paying special attention to where two pods touch, where a pod joins the branch, and any pod splashed with soil.

run your eye over the trunk and branch cushions (where the pods hang) for dark, wet, sunken cankers, and glance at the ground and leaf litter for rotten fallen pods — these are the spore stores that start each new round of infection.

unlike an insect pest, you do not wait for a percentage — a single spreading black pod, or the first white bloom, means spores are already loose in your plot, so remove it the moment you see it. And from the onset of the wet season, run weekly sanitation (picking and burying rotten pods) even before the first spot shows.

where a wet plot is under real pressure, a copper-based protectant fungicide shields the pods. Protectant means it only sits on the outside and blocks spores from landing — so it must go on before infection and be re-sprayed every 3–4 weeks through the wet season and after heavy rain washes it off; for high pressure a metalaxyl-copper mix (part systemic — meaning some of it is taken up inside the pod — for longer cover) can be used. Safety: cover your skin, eyes, nose and mouth; spray in the cool of the day with the wind at your back; keep the spray off food, drinking water, children and bees; respect the pre-harvest interval (the number of days the label tells you to wait between the last spray and picking pods); and wash yourself and your clothes afterwards. Resistance: never lean on the same systemic (metalaxyl) every time — alternate it with plain copper so the disease cannot learn to survive it.

if pods keep blackening, the leak is almost always missed rotten pods or a canopy still too wet — so walk the plot twice a week, remove every last diseased pod and cut any oozing trunk cankers back to clean, healthy wood, and open the shade further. If a tree is riddled with cankers and losing most of its pods season after season, cut your losses: it has become a spore reservoir feeding the whole plot, so remove or heavily rehabilitate it and replant with a tolerant hybrid so it stops reinfecting your healthy trees.