PESTS OF COFFEE
White stem borer Xylotrechus quadripes Cerambycidae: Coleoptera
- White stem borer is the most serious pest of Arabica coffee in India.
- Alternate host plants include Robusta tree coffee, teak, Oleadioica etc. However, borer usually does not breed in these plants.
- Adult is slender and 2.5 cm long beetle. Forewings are black with white bands.
- Infested plants show externally visible ridges around the stem. Such plants also exhibit yellowing and wilting of leaves. Young plants (7 to 8 years old) attacked by the borer may die in a year, while older plants withstand the attack for a few seasons. However, such plants are less productive, yielding more of floats.
Coffee berry borer Hypothenemus hampei Ferrari Scolytidae Coleoptera
- The pest damages young as well as ripe berries.
- Infested tender berries drop due to injury or secondary infection by fungi. In case of severe infestation, 30 to 80% of the berries are attacked, resulting in heavy crop loss.
- A typical pin hole at the tip of the berries indicates the presence of the pest. In case of severe infestation, two or more holes are seen
- Adult is a small black beetle. Larvae feed on the beans, making small tunnels.
Shot–hole borer or Ambrosia beetle Xylosandrus compactus Scolytidae: Coleoptera
- This insect has a wide host range like Anmota, Avocado, Clerodendron, cocoa, Crotalaria, croton, dadap, Dendrobium, mahogony, mango, neem etc.
- Adult beetle is brown to black with a short, sub cylindrical body. Body is covered with fine hairs.
- Pest infests green succulent main branches in young plants. After entering into the twig through the shot-hole made on the underside, female makes a longitudinal tunnel between the nodes.
- The beetle then lines the wall of the gallery with ‘ambrosia’ fungus, the spores of which are carried from the tunnel. Two species of ambrosia viz., Ambrosiella macrospora and A. xylebori have been recorded in India. After growing the fungus, female lays 50 eggs, in groups of 5 to 8. Eggs hatch in 2 to 3 days. The milky white larvae feed on the ambrosia and live for 13 to 21 days, and the pupal stage for about 11 days. Oviposition to adult emergence takes 4 to 5 weeks. All the life stages of the pest are seen in the same tunnel during the peak period of incidence.
- Withered or dried branches with shot-holes indicate the presence of the pest. Attacked branches dry up. Leaves above the point of attack fall prematurely. Terminal leaves wilt, droop and dry up. Withering is faster in young branches and delayed in older twigs. Severe infestation results in the loss of productive branches. Due to the loss of primaries, establishment of young plantations is delayed.
Red borer Zeuzera coffeae Nietner Cossidae Lepidoptera
- Red borer is a minor pest of Arabica and Robusta coffee.
- It has a wide range of hosts including tea, cinnamon, sandal, cotton, orange, teak and many forest trees.
- Adult of orange-red borer is a medium sized moth with spotted wings.
- After entering through the junction of leaf stalk and twig, larva constructs a tunnel in young plants, which even extends up to the roots.
- Larva causes damage by boring the stem or branches to feed on the wood. In advanced cases, the branch or the whole plant dries up.
Mealy bugs Planococcus spp. Pseudococcidae Hemiptera
- Mealy bugs infest tender branches, nodes, leaves, spikes, berries and roots in large numbers. Both nymphs and adults suck the sap. Young plants succumb to heavy infestation. Leaves become chlorotic, flower buds abort and berries become small if severely infested. A black fungus (sooty mould, Capnodium sp.) develops on the honeydew excreted by the bugs. Consequently, the leaves of infested plants become black, affecting photosynthesis.
- Among the cultivated varieties of coffee, Robusta and Cavery suffer the worst from mealy bug attack.
Green scale Coccus viridis (Green) Coccidae: Hemiptera
- They suck sap from the tender parts, congregating down on the undersurface of leaves close to the midrib and veins, on the green shoots, spikes and berries. The severe infestation results in death of the plant. The infested leaves may curl up and tender twigs droop. Honeydew excreted by the scale forms a layer on the leaves and acts as a medium for the growth of the “sooty mould”. This hinders photosynthesis, thereby weakening the plant.
Brown scale Saissetia coffeae (Walker) Coccidae: Hemiptera
Cockchafers or white grubs Holotrichia spp. Melolonthidae Coleoptera
Hairy caterpillars Eupterote spp. Bombycidae: Lepidoptera
Coffee bean beetle Araecerus fasciculatus Anthribidae Coleoptera
- It is a pest of coffee berries in the field and of beans in storage. Adult is pale grey with black spots, and entire body is clothed in a felt of fine hair.
- Infested coffee shows circular holes.
Snail Ariophanta solata Benson Ariophantidae Class: Gastropoda Phylum: Mollusca
Thrips Heliothrips haemorrhoidalis; Retithrips syriacus; Scirtothrips bispinosus; S. sweetmanni; Thrips nilgiriensis (Thripidae: Thysanoptera)