The control of black pod, canker and seedling blight of cocoa, caused by Phytophthora palmivora, with potassium phosphonate
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Trunk injected potassium phosphonate (8 or 16 g a.i. per tree every 6 months) controls black pod and stem canker of cocoa: Foliar sprays of potassium phosphonate (20 g a.i. per tree every 6 months) or Ridomil Plus 72WP (0.72 g a.i. per tree every 6 weeks during the wet season) do not control black pod. Trunk injection is less weather dependent than foliar sprays, and is a more effective application method for mature trees in the cocoa growing areas of Papua New Guinea. Single Ridomil Plus 72WP (0.8%) or potassium phosphonate (4%) sprays control artificially inoculated seedling blight more effectively than either a lower rate of potassium phosphonate (0.5%) spray or a soil drench of potassium phosphonate (1%).
KeywordsAustralasian Plant Pathology Downy Mildew Metalaxyl Foliar Spray Stem Canker
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