Validation of coloured sticky traps with LUREM-TR attractants for effective monitoring of thrips dynamics on French beans in Kenya

Thrips are among the key pests of French beans inflicting both quantitative and qualitative crop damage. Effective monitoring and timely implementation of pest management strategies is key for their management. Field experiments over two seasons were conducted to evaluate the response of pest thrips species infesting French beans to coloured traps with LUREM-TR attractant and validate the same for effective monitoring of thrips dynamics. Six treatments including three coloured traps: blue, yellow and clear sticky traps either with and without LUREM-TR attractant were evaluated. Blue traps caught 2.05 – 3.52 times as many thrips as yellow traps, and 22.07 – 29.31 times as many as clear traps. Blue traps were more attractive to Megalurothrips sjostedti (Trybom), Frankliniella schultzei (Trybom) and Frankliniella occidentalis (Pergande), while Hydatothrips adolfifriderici (Karny) was mostly attracted to yellow traps. LUREM-TR attractant increased thrips captures on coloured traps between 29.6 - 158.4%. Yellow traps where more attractive to aphids, whiteflies, hoppers, coccinelids and thrips natural enemies like Ceranisus sp. and Orius sp, while blue and clear traps were more attractive to dipterans and coleopterans, respectively. Total trap captures on blue traps with LUREM-TR correlated the most with absolute measures of thrips density on the plants. Weather parameters like mean maximum temperature and wind run significantly influenced the thrips population dynamics. The high proportion of thrips captured suggests that the blue sticky traps and LUREM-TR can be an important element for monitoring thrips dynamics on French beans in Kenya.