While citrus trees are vulnerable to a wide host of problems, fungal pathogens that cause trunk disease on your lemon trees can lead to rapid injury that gives home garden enthusiasts little time to react. Avoid trunk disease and keep your lemon trees healthy and productive by providing consistent care.
Trunk disease pathogens are more likely to attack stressed trees than vigorous, well-maintained lemon trees. Grow lemon trees in areas that provide full sunlight for vigorous growth and optimal fruit production. Citrus trees thrive in moist, well-drained soil with a preference for sandy loam soil, though other well-drained soil types are acceptable, according to the Alabama Cooperative Extension System.
Artist's conk is a fungal infection of lemon trees caused by the fungal pathogen Ganoderma applanatum. This fungus enters lemon trees through wounds, according to the University of California IPM Online. Rio Grande gummosis is another fungal trunk disease of lemon trees caused by the pathogen Diplodia natalensis. Rio Grande gummosis favors injured trees, as well, according to the Texas Agricultural Extension Service.
Artist's conk disease of lemon trees results in the rotting of wood within tree trunks where interior wood becomes a white hue, according to the University of California IPM Online. Conks, or shelf-like fruiting bodies, measuring 2 to 30 inches in width form on lemon tree trunks. Wood decay leads to tree death. Rio Grande gummosis of lemon trees results in the appearance of a gummy substance on trunks and branches that oozes from the development of trunk blisters, according to the Texas Agricultural Extension Service. Trees affected by gummosis are generally already damaged and will experience severely diminished health.
Keeping your trees vigorous and healthy extends beyond daily maintenance. Removal of potentially invasive weeds is essential in keeping your tree protected from pests that move from weeds to trees as host plants. Pest infestations create wounds and lead to diminished health that offers a prime environment for fungal infection. Manually remove weeds that crop up or if you choose to apply mulch to regulate moisture and control weeds, keep the mulch at a distance of at least 12 inches from your lemon tree to prevent foot rot problems, according to the AgriLife Extension.
Additionally, Rio Grande gummosis favors trees with freeze damage. Protect your lemon trees from the cold. Cover the top of your lemon tree with a lightweight material like a sheet as a protection from dropping temperatures; the sheet does not need to reach the ground but must be secure to prevent movement from wind.
For control of artist's conk and Rio Grande gummosis trunk disease on lemon trees, maintain vigorous trees, as there are no chemical or diagnostic management methods. Preventive care is your best option. Remove and destroy dead or affected plant parts whether or not an infection is present, but create clean cuts to avoid wounding your tree. Sanitize pruning tools between each cut and between uses on different plants to inhibit disease transfer.