Responses of flea beetles (Podagrica spp.) and okra plants (Abelmoschus esculentus L. Moench) to differently coloured polyethylene shades

Abstract

The response of flea beetles (Podagrica spp.) to visual cues produced by differently coloured polyethylene films, and the performance of okra plants grown under shades, were studied in Nigeria. In the first of our experiments, factorial combinations of seven shade contrasts and two okra varieties grown in pots were laid out in a completely randomized design. A second experiment comprised five differently coloured plastic water trap bowls laid out in the field in a randomized complete block design, with four replications. Okra plants covered with yellow polyethylene films consistently attracted significantly higher numbers of adult Podagrica than plants grown under other-coloured films. Plant height, stem diameter, leaf number and size were significantly higher under red polyethylene covers. The number of fruits harvested under the transparent (clear) cover was significantly higher than the number harvested under red, green or blue film polyethylene covers. Also, the yellow-coloured plastic water trap bowls caught consistently more flea beetles than bowls of other colours. Generally, the intensity of transmitted light and temperature varied only slightly under the various covers. Yellow reflectance from the polyethylene film was therefore inferred to elicit strong attractant responses in Podagrica; the implications of this for monitoring and management of Podagrica in the field are discussed.