Banana plants wilting and yellowing, inner stem turns brown when cut (kela)

Older leaves yellowing from the margins, then collapsing and hanging around the plant like a skirt, along with the pseudostem splitting at the base and brown to reddish streaks inside the stem when you cut it, point most likely to Panama wilt, a soil-borne Fusarium disease. It blocks the plant's water vessels, which is why it wilts. This is a serious disease that survives many years in the soil, so confirm it with your KVK before deciding, since bacterial wilt and waterlogging can look similar. There is no spray that cures an infected plant. Management is about prevention and containment: use only clean tissue culture or disease-free planting material, avoid taking suckers from affected fields, improve drainage because waterlogging worsens it, and do not move soil or water from infected patches to clean areas. Remove and destroy affected plants, and where the disease is established, switch to resistant or tolerant varieties recommended for your area, since some Cavendish types are very susceptible to certain races. Crop rotation and good soil health help. Ask your horticulture department which tolerant variety suits your zone and market before replanting.