As the potatoes grow keep weeds to a minimum, but do not hoe too deeply near the plants as the roots and tubers are relatively shallow. Remove and destroy insects as soon as they appear. Where crops are small, hand picking the pests is effective and safe. However, where this is not practical, sprays may be used - consult your local authority as to what chemicals are legal and effective. Where air is particularly moist and cool, early blight can kill the vines.
Blight appears first as purple blotches on the leave.
The blotches turn brown and rot. This disease can be prevented by spraying chlorothalonil or mancozeb on a weekly basis from the time the plants are six inches high. Scab is another disease that attacks potato plants. Do not put lime in soil before planting potatoes. Soil should be kept moist, but well-drained.