PEST MANAGEMENT DECISION GUIDE: GREEN AND YELLOW LIST
Green scale on coffee
Coccus viridis Coffee Green Scale
- Check that young nursery trees are scale-free before planting into or near older plantations.
- Use recommended spacing (single row 3x1m to 3x2m or double row 2x1m to 2x2m)
- Plant shade trees such as Leucena (lukin) to maintain 30% shade to encourage natural enemies
- Place sticky bands around stem bases or paint stem bases with sticky substance (at least 15 cm wide) to prevent ants from crawling up as ants protect scales from their natural enemies (e.g. lady beetles)
- Avoid planting host plants of green scales into the plantation, such as avocado, celery, flowering ginger, guava and orange.
- During the dry season, inspect for presence of little roundish shiny pale-green insects every 2 weeks. Look on the green wood and on the underside of leaves especially along the main leaf vein and near the tips of green shoots
- The young scales are flat and yellowish green covered with a hard 2 to 3 mm oval shield.
- The adult scales are shiny pale green with a tiny black, irregular U-shape at the back, just visible by naked eye.
- Infestations produce spots of honeydew on the stem and leaf, which become covered with a black dusty sticky mould
- Consider control measures when 10 or more leaves are each infested with one or more scales on the majority of trees
- Defoliation of badly affected trees can occur and action must be quickly taken to maintain tree vigour
- When plants are lightly infested, kill scales by rubbing them with your fingers to remove them from the infested twigs and shoots
- Prune and remove old branches and leaves in dry season to reduce scales
- Spray with soapy solutions (potassium soaps; add 10-15 tablespoons full of liquid soap to a 20 lt bucket) and apply only on the affected parts. Repeat weekly if necessary.
- Allow chickens into the plantation as they will sit on the tree branches and feed on the scale insects.
- There are currently no registered pesticides in Ethiopia to manage green scale on coffee
CREATED/UPDATED: February 2017
PRODUCED BY: Plantwise
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