Scale Insect: Aspidiotus destructor

Symptoms of Damage:

• It occurs more in summer. Scale insects affects on leaves and nuts of coconut palms.
• A severe infestation, scale forms a continuous crust over flower spikes, young nuts and lower surface of leaves.
• On leaves, A. destructor causes scales with yellow spots developing where the crawlers have settled and grown into adults.
• Nymphs reside and develop in leaf by sucking the sap.
• Entire leaves may turn yellow to brown and fall. Sooty mould may develop. The bright yellow colour of affected coconut palms is clearly visible from a great distance.
• In extreme cases, the leaves dry out, entire fronds drop off and the crown dies. Heavy infestation results in stunting of new leaves, reduction of crop yield or complete crop failure.
• Infested coconut fronds exhibit yellow areas on the upper surface, formed by numerous yellow spots each marking the position of the coconut scale on the under surface.

Scale on leaves	Scale on coconut	Yellow spots on leaf

Identification of the Pest:

• Egg: hatching the young scales on the undersides of the leaves.
  
• Nymph: Covered with circular waxy secretion
  
• Adult: The scale is bright yellow and round or reddish (female) and oval (male) covered with semitransparent grayish white flat scale. Females are always wingless and remain under their scale their entire life. Adult males have one pair of membranous wings, move about actively in search of females and do not feed during adult stage.

Nymph	Adult

Management:

Chemical Method:

• Spray Fish Oil Rosin Soap (FORS) 2.5% or spray Malathion. A second round is given after 20 days.

Biological Method:

• Release of predatory Coccinellids, Chilocorus nigritius is found to be effective.