Witches'-broom of lime

Witches'-broom of lime is a devastating plant disease caused by a specific type of phytoplasma, known as Candidatus Phytoplasma aurantifolia. These pathogens inhabit the plant's phloem, disrupting the translocation of nutrients and causing systemic hormonal imbalances throughout the host tree.

This condition primarily affects Citrus species, with lime (Citrus aurantifolia) being particularly susceptible. The disease is highly destructive in tropical and subtropical citrus-growing regions, often leading to total loss of productivity and premature decline of the orchard if left unmanaged.

Symptoms are distinct and easily identifiable: the tree develops dense, broom-like clusters of short, thin, and stunted shoots. The foliage on these branches is typically chlorotic, smaller than normal, and may show signs of crinkling or deformation, significantly reducing the tree's photosynthetic capacity.

The disease is transmitted primarily by insect vectors, such as the lime psyllid. Environmental conditions that support the rapid multiplication of these insect vectors—such as warm, humid weather—greatly increase the risk of disease transmission across the entire citrus plantation.

Management of Witches'-broom of lime is challenging, as there are no chemical cures for established phytoplasma infections. Therefore, proactive management strategies are essential for orchard longevity:

• Strict quarantine and use of pathogen-free certified nursery stock.
• Integrated Pest Management (IPM) to control psyllid populations with insecticides and biological agents.
• Regular monitoring and rapid identification of symptomatic branches or trees.
• Immediate removal and destruction of infected trees to eliminate the source of inoculum for other trees.