Bud drop
Flower buds yellow and fall before opening, usually because the plant has been stressed by changes in water, light or temperature.
Also known as: Flower bud drop, Bud blast
Symptoms and identification
Healthy-looking buds turn yellow or brown at the stalk and drop off, often many at once. Leaves may look normal. It is common on hibiscus, jasmine, orchids, Christmas cactus and fruiting vegetables.
Causes
Sudden changes stress the plant: moving the pot, irregular watering, cold draughts or air conditioning, very hot weather, low light or overfeeding. Pests such as thrips and gall midges inside buds can also cause it.
Organic treatment
Find and correct the cause. Check fallen buds for insects; if you find any, remove affected buds and spray with neem oil. New buds usually develop normally once conditions are stable.
Prevention
Keep conditions steady while buds are forming. Water evenly, avoid moving plants once buds appear, and protect them from draughts and sudden temperature changes.
Chemical treatment (use with care)
Not needed unless a pest is confirmed, in which case use a product labelled for that pest.