Enhancing Monitoring Efficiency and Management of Vectors of Maize Lethal Necrosis Disease in Kenya

Abstract

This study was carried out to determine the best monitoring strategy to follow as part of management practice for vectors of maize lethal necrosis disease (MLND). The trial was carried out in a randomised complete block design, with four replications in two seasons, from 1st April 2015 to 8th April 2016, in Bomet County, Kenya, the epicentre of the disease. Blue and yellow sticky traps were tested for trapping efficiency when placed at four angles (90°, 120°, 150°, and 180°). Blue and yellow sticky rolls were also tested for their trapping efficiency at different installation times (at germination, and 1 and 2 weeks after germination),and using a control without sticky rolls. Further trials included sampling and planting orientation. Traps positioned at 90° significantly (P ≤ 0.001) trapped more corn thrips, as compared with the other positions. Blue sticky rolls trapped one-fold more corn thrips than yellow rolls. In contrast, yellow sticky rolls trapped one-fold more corn leaf aphids than the blue rolls (P ≤ 0. 001). Corn thrips infestation was better estimated by sampling along the maize rows than sampling across the rows, by almost half-fold (P ≤ 0.001). Maize planted along a north–south orientation became more infested by corn thrips than plants along an east–west orientation (P ≤ 0.04). The findings strongly suggest that sticky traps and sticky rolls should be included in the management of vectors of MLND-causing viruses. The role of maize-row orientation requires further investigation as part of cultural practice in managing the disease. Sampling along maize rows will better estimate the vector population, allowing for the deployment of appropriate measures at the earliest time. It is recommended that these effective tools be promoted for farmers to gain from their use.