African citrus psyllid

Systematic position. The African citrus psyllid, Trioza erytreae, belongs to the order Hemiptera and the family Triozidae. It is a highly destructive insect pest that primarily affects citrus production, acting as a major threat to the industry due to its feeding habits and disease transmission capabilities.

Host plants and damage. This pest primarily infests plants in the Rutaceae family, with a strong preference for citrus species such as lemon, orange, lime, and grapefruit. The damage is caused by both adults and nymphs feeding on succulent young leaves and shoots. This feeding results in leaf deformation, curling, the formation of pit-like galls, and overall tree vigor loss.

Biology and life cycle. The life cycle involves egg, five nymphal stages, and adult stages. Females lay eggs on the edges of young flushing leaves. Nymphs remain sedentary in specialized pits during their development. The rate of reproduction is closely tied to environmental conditions, with the species thriving in cool and humid climates where it can complete multiple generations in a single year.

Economic impact. The primary economic threat posed by Trioza erytreae is its role as a vector for the bacterium Candidatus Liberibacter africanus, the causal agent of African citrus greening disease. Infected trees exhibit yellowing, premature fruit drop, and eventually complete decline, rendering entire orchards unproductive and threatening local citrus markets.

Protection measures. Management of this pest requires a combination of regulatory and cultural tactics:

• Strict quarantine regulations to prevent the movement of infested nursery stock between regions.
• Routine field monitoring using yellow sticky traps to detect early population spikes.
• Chemical control using systemic insecticides applied during critical flush periods to protect new growth.
• Integrated Pest Management (IPM) practices, including the preservation of natural predators like parasitoid wasps.
• Regular pruning of infested shoots to reduce the localized population density and disrupt the cycle.