We have written articles about the coffee industries recent encounter with pests and diseases which contributes to its low production. From the Black Coffee Twig Borer which is harming coffee farms in East Africa, the Coffee Berry Borer making its way in Kona, Hawaii, and the Coffee Rust experience in Central America.
These news left us wondering, as coffee lovers, what other pest and diseases can affect our beloved coffee tree. And we came upon a coffee disease which usually occurs in seedling nurseries. It affects plant leaves and tissues. We are talking about a coffee disease known as Bacterial Blight of Coffee, or also known as Elgon Die-back.
This coffee disease was first known in Garca, Sao Paulo, Brazil. It is caused by a Bacterium Pseudomonas Syringae pv Garcae. This bacterium can be found on all healthy parts of the coffee tree. Cool and wet weather triggers the multiplication of the bacteria, which can cause a epidemic when it spreads rapidly.
Bacterial Blight of Coffee
- Lesions appear on leaves, water soaked margin and black at start of infection. Leaves eventually dry up and roll inwards turning brown.
- Dead and dried leaves do not shed but remain attached to the plant.
- Terminal bud is attacked. Infection then extends downwards, resulting in die-back.
On young succulent branches:
- Infection starts from the stipules, then entire node is attacked. Infection spreads to internodes. Branch then dies above the blackened node.
- Internodes infection as a result of hail damage or through wounds caused by sucking insects. This is not a common
- mode of infection.
On flowers and pinhead stage:
- Entire trusse or pinheads may be attacked and appear black and water soaked.
- Flowers and pin-heads shrivel and turn black.
- The entire crop may be lost.
Highlights on Good Agricultural/Hygienic Practices
- Avoid indiscriminate use of fungicides to prevent pesticide residue accumulation.▪ Sterilise all implements used on diseased plants.
- Severe infection leads to death of twigs and branches which reduces yield and bean quality.
- Only recommended fungicides should be used.
Avoid planting materials from BBC known areas
Management of BBC
- Cut off infected twigs and branches.
- Plant shade trees and wind breaks on exposed sides of BBC areas.
- Observe field hygiene by disinfecting tools used for pruning infected trees with a suitable disinfectant such as Kerol 0.1 % , Lysol 3%.
- Avoid planting materials from known BBC areas.
- Critical spray time is just before, during and after flowering especially when these coincide with wet weather.
- Complete first spray by mid-February and continue through the rains at two week intervals and after rains at three week interval .