Management of Pests

Acknowledgment:
This guide is adapted from the Coffee Industry Corporation (CIC) PNG Coffee Handbook 2016. We have simplified the content for easier understanding by farmers.

Pest 1: Scale Insects

  • Introduction
    • Green scales (Coccus spp.) feed on coffee and other plants in PNG.
    • Occur in most coffee-growing areas; attack both Arabica and Robusta.
    • Ants are always associated, feeding on honeydew.
    • Two species: C. celatus (dark green) and C. viridis (pale green); field identification requires a specialist.
    • Natural enemies: Coccinellid beetles, fungi, parasitic wasps (seldom control heavy infestations).
  • Description and Damage
    • Adult females oval, flat, up to 4 mm long × 2 mm wide.
    • Favor young shoots and lower canopy; citrus is an important alternative host.
    • Sap-sucking; excrete honeydew promoting sooty mold.
    • Severe infestation → 21% flower loss, 16% fruiting node loss, ~50% cherry loss.
    • Ants protect scales, remove honeydew, transport scales, build shelters.
  • Control
    • Chemical:
      • Ants: Dursban EC, Losban EC, Cislin 25, Bifenthrin EC, Amdro bait (2 applications before & after flowering).
      • Green scales: White Oil (dry season) or White Oil + Malathion 500 EC (3 applications monthly).
    • Biological: Parasitic wasp Metaphycus baruensis, Coccinellid beetles, Verticillium lecanii, native wasps.
    • Cultural: Prune lower branches during peak adult scale population (Nov–Dec).
    • Integrated: Combine chemical, biological, and cultural methods.

 

Pest 2: Coffee Berry Borer

  • Introduction
    • Hypothenemus hampei (small black beetle 1.5–1.8 mm).
    • Females bore into berries, lay eggs inside beans.
    • Not yet in PNG; present in nearby Indonesia and New Caledonia.
  • Description and Damage
    • Eggs: 30–120 per tunnel; larvae feed inside beans.
    • Crop loss: 30–80% in severe infestations.
    • Damaged beans affect grading and market quality.
  • Host Range
    • Monophagous on Coffea species: Arabica & Robusta susceptible; Liberica resistant.
    • Other plants used only for feeding, not supporting life cycle.
  • Ecological/Cultural Factors
    • Influenced by altitude, temperature, rainfall, and cultural practices.
    • Favored by heavy shade, close planting, unpruned trees, continuous flowering, fallen cherries.
  • Dispersal
    • Females fly to new cherries; long-distance assisted by wind.
    • Spread by humans (beans, clothing, packing materials).
  • Control
    • Sanitation: Remove all cherries (on tree & ground), off-season flowers.
    • Host Plant Resistance: Use Liberica as barrier crop.
    • Chemical: Confidor (Imidacloprid).
    • Biological: Parasitoids: Cephalonomia stephanoderis, Prorops nasutu, Phymastichus coffea, Beauveria bassiana.

 

Pest 3: Coffee Ring Borer

  • Introduction
    • Meroleptus cinctor attacks coffee in nurseries & smallholder fields; common host is sweet potato.
  • Description and Damage
    • Adults: brown/black, ~7 mm; larvae off-white with dark heads.
    • Larvae tunnel around trunk, feed on inner bark & outer wood.
    • Young trees: wilting & dieback; older trees: damage often repaired.
  • Control
    • Remove sweet potato from planting areas.
    • Cut & burn infested uprights.
    • Brush-on Lorsban 0.5% on trunk effective; foliar sprays usually ineffective.

 

Pest 4: Leafhoppers

  • Introduction
    • Leafhoppers (Hemiptera: Cicadellidae) feed on coffee sap.
    • Common species: Batrachomorphus spp., Archeguina spp.
  • Description and Damage
    • Small, slender, long-bodied insects; females brown, males dark green/blue.
    • Eggs in internodes; nymphs black → green, feed on sap.
    • High populations → reduced vigour, stunted growth, yellowing, wood warping.
  • Control
    • Natural enemies: parasitic wasps, predatory insects.
    • Chemical: Basudin, Actellic 50 EC, Orthene 75 (foliar spray when population high).

 

Pest 5: Coffee Centre Borer

  • Introduction
    • Zeuzera coffeae attacks coffee, citrus, cocoa, tea, kapok, ornamentals.
  • Description and Damage
    • Adults: grey/white with black dots; females larger (5 cm wingspan), males smaller (4 cm).
    • Larvae bore into branches, cylindrical tunnels, reddish-brown frass; killed branches.
  • Control
    • Prune & burn infested branches.
    • Parasitic wasps & predatory insects help regulate populations.

 

Pest 6: Coffee Leaf Roller

  • Introduction
    • Hamona coffearia feeds on coffee leaves; alternate hosts: Crotalaria, Dahlia, Albizzia, wild hops, silky oak.
  • Description and Damage
    • Larvae dull green/blue-green; pupate in rolled leaves.
    • Eggs laid in scale-like masses of 20–40.
    • Life cycle ~8 weeks; up to 80% defoliation in severe attacks.
  • Control
    • Natural parasitism up to 60%.
    • Chemical: Orthene or Karate 75 (0.25% spray on leaves at larval stage).

 

Pest 7: Cicadas

  • Introduction
    • Occasionally problematic; numbers increase with shade removal, litter loss, insecticide use.
  • Description and Damage
    • Adult females lay eggs in primaries; nymphs drop to soil & feed on rootlets.
    • High populations reduce nutrient uptake, mimicking dieback.
  • Control
    • Natural enemies: Cordiceps spp., Metarrhizium spp., Rhipiphoridae larvae, ants.
    • Long-term: plant shade trees, maintain litter layer.

 

Pest 8: Army Worms

  • Introduction
    • Spodoptera exempta seasonal; affects coffee, grasses, some fruit & root crops.
  • Description and Damage
    • Adults robust, light brown, ~40 mm; larvae ~40 mm, cream-yellow stripe.
    • Larvae feed on leaves & immature cherries; life cycle 21–30 days.
    • Density 16–25 larvae/tree → significant defoliation.
  • Control
    • Monitor fields for feeding larvae.
    • Chemical: Orthene 75 or Maldison 500 (foliar spray at larval stage, rotate if needed).

 

Pest 9: Shot Hole Weevil

  • Introduction
    • Oribius spp. minor pest; found in most coffee-growing regions.
  • Description and Damage
    • Adults ~5 mm, dark brown/black; feed on leaves causing small holes.
  • Control
    • Weed control to reduce host plants.
    • Chemical only if severe: Dursban, Malathion, Imidacloprid.
    • Biological: Beauveria bassiana (spray on foliage, branches, base; 2 applications Oct–Nov).

Article Details

Article ID:
13
Category:
Views:
1
Rating (Votes):
(0)

Related articles