Coffee Rust Disease Symptoms

The first  symptoms of rust are the spots with a powdery appearance and yellowish colour found on the underside of the leaves.  Lesions may first appear as small yellow-coloured spots which change colour to bright orange. Rust sori are characterized as oil spots on the upper leaf surface.  A yellow-green diffuse halo may surround lesions.  Eventually the lesions may become necrotic, turning gray or brown.  Extensive defoliation can weaken and eventually kill coffee plants.  In contrast, H.coffeicola does not produce distinct spots, but rather the spored completely cover the lower surface of the leaf.

References.
Thurston, H.D. 1998. Tropical Plant Diseases. American Phytopathological Society, St. Paul, MN.

Location: Minas Gerais region, Brazil.

Objective: compare OMEX Zynergy with and without standard fungicides for plant disease levels and productivity in coffee plantation

OMEX treatment: Total of 3.0 litres of OMEX Zynergy per hectare and 3.0 litres of OMEX Bio 20 in three applications of 1.0 + 1.0 litres with intervals of 30 to 40 days.

OMEX and fungicide products were applied together in a volume of 400 litres of water per hectare.