Acid Lime Diseases
Twig Blight
Symptoms
Symptoms on Twigs and Branches:
- Dark, Sunken Lesions: Infected twigs develop dark, sunken lesions or cankers that may extend along the length of the twig. These lesions can have a slightly raised margin and may crack as they expand.
- Twig Dieback: As the disease progresses, the infected twigs may die back from the tips. This dieback can spread down the twig and affect larger branches.
- Girdling of Twigs: Severe infections can girdle the twigs, cutting off the flow of nutrients and water, which leads to the death of the twig beyond the lesion.
- Exudation of Gum: In some cases, infected twigs may exude a sticky gum as a response to the infection.
Symptoms on Leaves and Fruit:
- Leaf Blight: Infected twigs may cause the leaves on those twigs to yellow, wilt, and eventually drop prematurely.
- Fruit Symptoms: Although primarily affecting twigs, in severe cases, the infection can spread to the fruit, causing similar sunken lesions and leading to fruit drop.
Signs of the Pathogen:
- Fungal Structures: Under wet conditions, tiny black fungal fruiting bodies (pycnidia for Phomopsis citri or acervuli for Colletotrichum gloeosporioides) may be visible on the surface of the infected bark.
Management
- Avoid Overwatering: Reduce overhead irrigation or avoid watering in the late afternoon or evening to minimize leaf wetness and the duration of moisture on plant surfaces.
- Pruning and Sanitation: Regularly prune out and destroy infected twigs and branches. Make cuts several inches below the visible symptoms to ensure complete removal of the infected tissue. Disinfect pruning tools between cuts with a bleach solution (1 part bleach to 9 parts water) to prevent spreading the disease.
- Timing of Application: Fungicide applications are most effective when applied preventively before symptoms appear, especially after pruning or during wet weather conditions
|
Fungicide |
Dosage |
|---|---|
|
0.3-0.5 g/ltr |
|
|
1 g/ltr |
