Papaya mealybug infestation in Nigeria: incidence, spread, abundance and damage estimate on pawpaw

The papaya mealybug, Paracoccus marginatus Williams and Granada de Willink, is a small hemipteran insect recently introduced in Nigeria that attacks several genera of host plants, including economically important tropical fruits, vegetables and ornamentals.
A survey was conducted in 2014 and 2015 to assess its spread, abundance and damage levels on pawpaw in orchards and homestead trees.
The survey covered 23 states of Nigeria distributed in various agro-ecological zones which included Swamp forest, Rainforest, Forest-Savannah transition, Southern Guinea Savannah, Northern Guinea savannah and Sudan savannah.
Sites for sampling were earmarked at 20 km intervals.
Five pawpaw plants were selected at random per site for observations on the infestation levels and damage of leaves and fruits.
Other plants in the vicinity of pawpaw were also sampled.
Infestation/damage were scored 1-4 corresponding to 0->50 infestation/damage of leaves/fruits.
A total of 116 sites were surveyed.
Papaya mealybug attacked the leaves and fruits of pawpaw.
Eighteen (18) alternative hosts were also attacked.
The percentage of infested plants in 2014 and 2015 ranged between 0 and 57% and 29-70% respectively.
Rated population levels on leaves and fruits of pawpaw ranged between 0 and 2 and 0-4 in 2014 and 2015. Similarly in both years, damage severity ranged between 0 and 3 and 0-4 in the visited sites.
Infestation increased in the survey of 2015 compared to the survey of 2014. The consequences of rapid spread of papaya mealybug on horticultural plants was discussed.

XXX International Horticultural Congress IHC2018: V International Symposium on Plant Genetic Resources and International Symposium on Applied Functional Molecular Biology

V.C. Umeh, G. Goergen, O. Ajuonu

Carica papaya, horticultural plants, mealybug, Paracoccus marginatus, Nigeria

https://doi.org/10.17660/ActaHortic.2020.1297.36