Pests and diseases

Pests and diseases
    Pests
    • The grubs of cockchafer beetles (Holotrichia repetita, Rhizotrogus refus, Serica nilgiriensis, Popilla chlorion, etc.) cause serious damage to the seedlings in South Indian plantations. The adults of these beetles come to the surface during summer and should be flushed by irrigating the seed-beds with water mixed with crude oil emulsion. The beetles must be then hand-picked and killed.

    • Crickets also cut the young seedlings and drag them to their haunts in the seed-beds. The haunts must be searched and the insect killed. The application of tobacco decoction with kerosene or phenyl wards off these insects.

    • The tea-fly (Helopeltis antonii and H.cinchoniii) infest the leaves in nurseries and also in the main field. These insects cause leaf-curl by sucking the juice form the tender leaves. If heavy damage is noticed, sodium arsenate mixed @ 28 g with 113 g of molasses in 9 litres of water may be sprayed on the plants for controlling these insects. The leaf bug, (Disphinctus humeralis), is occasionally found on tender foliage.

    Diseases
    • Stem blight caused by Sporotrichium and Verticillium spp., seedling blight due to Phytophthora parasitica, root-rot due to Phytophthora cinnamomi, and Sclerotium rolfsii and damping-off due to Pythium dexans and Rhizoctonia solani are some transplant bed-diseases affecting cinchona seedlings.

    • The spread of these diseases can be checked by scooping out the soil in the diseased patches all around, to a depth of 10 cm and throwing it away.

    • The cavity, so formed, may be filled with sterilized, dry soil.
    • The nursery-beds should also be drenched with mercurial fungicide to check the spread of the diseases.

    • Die-back or pink disease is caused by Pellicularia salmnicolor.

    • This organism attacks the tender tips of the stems and branches and gradually spreads. The branches should be pruned to prevent the spread of the disease.

    • Besides, the fungus Armillaria mellea causes root rot and Rosellinia spp. causes leaf spot diseases.

Last modified: Tuesday, 3 April 2012, 6:24 AM