1) White stem borer, Xylotrechus quadripes; Coleoptera: Cerambycidae
White stem borer of coffee is an important insect pest. Three species of coffee stem borer i.e. Xylotrechus quadripes, X. semei, and X. annulutus have been reported in Nepal. Among them white stem borer is an economically important pest of coffee. White stem borer adults are slender, long beetle measuring about 2.5 cm. Forewings are black in color with white bands. Males are generally smaller than females. Head shows distinctly raised black Ridges and the Hind Leg Femur extends beyond the apex of the Elytra while these characters are missing in females.
Damage: Damage to coffee plant is caused by grub. After hatching grub enter into the hardwood and make tunnels. Tunneling may extend even into the roots. Tunnels are tightly filed with the excreta of the grubs. The infested branches wilt and break easily. Infested plants show visible ridges around the stem. Yellowing and wilting of leaves can be seen. Young plants (mostly 7 to 8 years old) attacked by the borer may die in a year.
- Maintain optimum shade on the estates.
- Collect and destroy beetles mechanically especially during egg-laying period.
- Field release of predators Apenesia sps for biologically effective control of white stem borer.
- Collars prune the infested plants.
- Uproot and burn the affected parts, maintain clean sanitation.
- Remove the loose scaly bark of the main stem using coir glove or coconut husk to kill the eggs.
- Scrubbing during flight periods to kills the eggs and grubs present in the bark region. Deep scrubbing should be avoided (sharp implement may injure the green wood and eventually kill the plant).
- Spraying the main stem and thick primaries with neem kernel extract may afford good control of the pest.
2) Coffee berry borer, Hypothenemus hampei
Symptom of Damage:
- Pin hole at the tip of the berries (novel region)
- In severe infestation two or more holes may be seen.
- Female beetle bores into the berries through the navel region make tunneling and feed inside content.
- Powdery substance comes out through the holes
- Proper adoption of cultural practices and phytosanitary measures for effective management of coffee berry borer.
- Transportation of infested coffee to uninfected areas is the main reason for spread.
- Crop bags should be fumigated before delivery to estates to avoid cross infestation.
- Timely harvest of berries helps to reduce infestation.
- Reduce gleaning – spreading gunny bags or polythene sheets on the ground after picking the berries minimize gleaning.
- Maintain optimum shade and good drainage in the estate.
- Dipping infested berries in boiling water for 2-3 minutes kills all the stages of pest inside.
- Drying of coffee beans – prevents breeding of beetles in stored coffee based on moisture content level. Arabica (10% moisture content) – 16kg/lit. Roubsta (11% moisture content) – 18kg/lit
- Install attractant trap to collect and kill the beetles
Minor Insects Pests:
- Shot hole borer, Xylosandrus compactus
- Mealy bugs, Planococcus spp.
- Green scale, Coccus viridis (Green)
- Brown scale, Saissetia coffeae
- Coffee bean beetle, Araecerus fasciculatus