Aromatic Plants> Palmarosa> Diseases

Red Leaf Spot (Colletotrichum Graminicola)

The disease is much prevalent in all the Palmarosa growing regions and appears during rainy season. Under warm and humid conditions, the disease spreads rapidly and may cause up to 35 % reduction in the oil production. The disease perpetuates on the left-out stumps and stubbles on the field. The symptoms can be seen as small brownish spots, scattered all over the ventral surface of the leaves. The disease also infects the leaf sheaths and midrib.

Control : Two Sprays of Bavistin (0.1%) just after the first appearance of the disease at an interval of 20 days or three sprays of Dithane M-45 (0.3%) at an interval of 10-20 days controls the disease.

Little Leaf or Grassy Shoot (Balansia Sclerotia)

The disease is attacks the floral parts and consequently the oil yield and seed production is adversely affected. The characteristic symptoms are stunting and formation of little leaf on the plants in place of normal inflorescence.

Control : Spray Dithane Z-78 (0.3%) before flowering stage at an interval of 10-12 days.

Smut (Tolyposprium Christensenii)

This is an inflorescence borne disease adversely affects the oil yield and seed production. The symptoms are characterized by the transformation of seed into the smut sori, which are slightly long covered by dull yellow membrane.

Control : Seeds should be treated with organomercurial fungicides before sowing in the nursery. Spraying Dithane Z-78 (0.3%) just at the time of flower initiation is effective in controlling the disease.