1. Seasonal Abundance (2015–16 Field Study Findings)

• Adult population peaks per leaf:

  • July (1st & 2nd fortnight): 3.5 and 4.5

  • December (1st & 2nd fortnight): 4.75 and 4.00

  • April (2nd fortnight): 4.75

  • May (1st fortnight): 5.00

  • Absent during remaining months.

• Nymph population peaks per leaf:

  • July (1st & 2nd fortnight): 32 and 34.5

  • Lowest: June (1st fortnight): 6.25

• Egg spirals (per 5 leaves):

  • Highest: December (2nd fortnight) – 14.25

  • Also notable: June – 12.5; March – 10.63

  • Lowest: October (2nd fortnight) – none; November (1st & 2nd) – 0.25 and 0.5

2. Environmental Correlations

• Temperature:

  • Positive correlation with nymph and adult populations.

• Relative Humidity (RH) & Rainfall:

  • Negative correlation with nymph and adult populations.

• No significant relation between environmental parameters and egg incidence.

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3. Life Cycle & Morphology

• Egg stage:

  • Laid in spirals on undersides of young leaves, 35–50 per batch

  • Hatch in 4–12 days depending on conditions

• Larval stages:

  • 1st instar: mobile, dusky, with dorsal glandular spines

  • Later instars: sessile, dark with spines and wax, stacked exuviae

  • 3rd instar: black with green anterior spot

• Pupal stage (4th instar):

  • Females: ~1.25 mm; males: ~1.0 mm

  • Black with many dorsal spines and a waxy fringe

  • Used for species identification

• Adult:

  • Females larger (1.7 mm) than males (1.33 mm)

  • Dark-grey wings (with metallic sheen); orange to red body initially, darkens later

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4. Host Range & Polyphagy

• Polyphagous; prefers citrus

• Recorded on 75–169 plant species from 38–69 families

• Can persist on mango (Mangifera indica) for multiple generations

• Infestation on non-citrus is limited to 3 generations, rarely causes serious damage away from citrus

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5. Symptoms of Infestation

• Sticky honeydew → leads to black sooty mold

• Leaf distortion

• Presence of black spiny lumps on leaf undersides

• Ants often attracted to honeydew

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6. Development & Generations

• Tropical climate: All stages present year-round; reproduction halts in cold

• Development durations:

  • Egg: 11–20 days

  • Instars: 7–16, 5–30, 6–20 days

  • Pupal stage: 16–80 days

  • Adult lifespan: 6–12 days

• Life cycle: 2–4 months

• Generations/year: 3–6

• High mortality: Up to 77.5% in development

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7. Environmental Preferences & Limits

• Optimal temperature: 28–32°C

• Optimal RH: 70–80%

• Development threshold: 13.7°C

• Cannot survive:

  • Below 0°C

  • Above 43°C

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8. Management Implications

• Target peak periods: April–May, July, and December for control measures

• Monitor nymph and adult activity as it aligns with temperature trends

• Avoid excessive irrigation during these months to reduce RH-related risk factors

• Natural enemies: Their activity is density-dependent on pest populations, hence conserving them during pest surges may help in biological regulation

  Source: CABI