Distribution and damage characteristics of Analeptes trifasciata Fabricius 1775 (Coleoptera: cerambycidae) on cashew (Anacardium occidentale linnaeus 1753) in Nigeria

The infestation of cashew, Anacardium occidentale by Analeptes trifasciata, is on the increase and poses serious threat to cashew cultivation in Nigeria. There is dearth of base-line information on A. trifasciata in Nigeria. This study was conducted to provide more information on the distribution and damage characteristics of the pest in Nigeria. A survey of infestation by A. trifasciata was carried out in the Federal Capital Territory and 25 States of Nigeria that grow cashew in order to ascertain the geographical spread of the pest. A random sampling of 1000 cashew trees was carried out in each State. The monthly distribution and damage assessments of the pest were carried out at the Cocoa Research Institute of Nigeria (CRIN) Ibadan cashew research plots (N7/3, SW3/2, SS6) and its Ochaja Sub-station plots (NW1, NW7, SE5A) by sampling 100 randomly selected cashew trees at each plot. Data generated were analyzed with Student’s T-test. Analeptes trifasciata was found in South-East, South-West, South South and North-Central geopolitical zones of Nigeria. Pronounced infestation levels of 42.7% to 82.6% were recorded, the highest in Kogi State (82.6%) followed by Oyo (79.3%), Abia (62.4%), Imo (61.3%), Osun (61%) and Anambra (59.3%) States. The devastating effects of the insect were not noticed in Akwa-Ibom, Bayelsa and Rivers States. Peak infestation (117 130 adult Analeptes) per plot was recorded in September to December, and least (7 Analeptes) in June. Analeptes trifasciata population was more abundant in Oyo State (554.3 ± 41.3) than Kogi State (360.7 ± 42.4). However a higher number of girdled-branches, 535.8 ± 27.6/hectare was recorded for Kogi State when compared with 323.7 ± 18.4 for Oyo State. The wide spread of A. trifasciata infestation in most cashew growing states has made it an economic pest. The girdling of cashew by the adult insect in highly infested plantations leads to significant damages. Control measures in Nigeria should target the peak periods of infestation to reduce losses in cashew production.