Also called Mexican lime or West Indian lime, key lime (Citrus aurantifolia) is a low-growing, stout tree having dense, pale green leaves, fragrant, spring-blooming flowers that creates oval or round, thin-skinned limes that boast juicy, acidic pulp. The key lime is vulnerable to a host of issues, many of which may be prevented with proper cultural care.

Nutrient Deficiencies

Key limes prefer rich, well-draining soil, and though they’ll tolerate less than perfect soils, soil which is too bad in quality can lead to nutrient deficiencies. Yellowing leaves, premature leaf drop, and poor fruit production might be a sign of nutrient-deficient soil. A lack of zinc from the soil can cause leaves to appear stunted, pointed and shriveled, while a lack of phosphorus may lead to hollow fruit placed in a rough rind. Fertilizing sometimes with a balanced fertilizer can help remedy nutrient deficiencies in the soil.

Pests

Key lime trees could possibly be bothered by insects like mites, tiny insects which might be rust brown, dark red, purple, yellow or dark green; scale insects, which seem like lumpy, scalelike rays on the leaves, limbs or trunk of this tree; and aphids, tiny colonies of insects which feed on new growth. Horticultural oil or foliar sulfur sprays will typically control scale and mites, while aphids may often be washed away from the tree using a direct flow of water. Insecticidal soap can also be handy for more severe infestations.

Diseases

Citrus canker is a serious bacterial infection that strikes key lime trees, spreading from infected trees via windy rain, animals or contaminated equipment. Initial symptoms consist of tiny spots on fruits and leaves which become raised spots, surrounded by a yellow ring. The illness worsens, causing leaves to drop and threatening the overall health of the tree. Other ailments include greasy spot, which causes oily lesions on leaves, and citrus scabthat triggers corky brown scabs on leaves and fruit. If applied regularly, copper-based fungicide can help control these diseases.

Prevention

Excellent tree health is the best weapon against diseases and insects. Follow appropriate citrus care guidelines by raising the tree in a bright, sunny place in U.S. Department of Agriculture plant hardiness zones 9 to 11. Water young key lime trees about one or two times every week, and reduce watering once the trees are established. Avoid unnecessary pruning to keep from accidentally injuring the tree back and inviting in insects and disease.

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