Scope to Maximise Rice Yellow Stem Borer Moth Catch in Delta Type Pheromone Traps

Abstract

The yellow stem borer (YSB), Scirpophaga incertulas (Walker), is a major pest of rice in Asia and pheromone trapping technology is emerging as a promising eco-friendly IPM tool for more sustainably managing this pest. To identify more efficient trap design so to maximize the efficiency of attracting and retaining the male moths in pheromone-based trapping system, a common methodology-based network study was taken up to compare the moth catches in alternative sex pheromone-baited Delta traps of varying attributes versus the commonly used Funnel (sleeve) trap at three major rice growing locations (Coimbatore, Tirurkuppam, Tirupathisaram) in Tamil Nadu, India within the same season during 2017-18. The results from the concurrent six week trap catch studies clarified that two superior Delta trap variants caught significantly more YSB moths than the funnel trap at all three locations. The moth catches were about 4-5 times greater in the normal size Delta trap (32x20x11cm) compared the Funnel traps, while even the smaller size Delta trap (22x12x7.5cm) caught nearly 2 times more moths than Funnel traps. The attribute of additional vents on the side roof of Delta traps was found to enhance the moth catch in Delta trap significantly. The relative moth catches among the five Delta trap variants versus Funnel trap at each location are also illustrated, along with results of pooled analysis over the locations, which confirmed the consistent superiority of Delta trap versions and the extra benefit from additional vents as trap attributes in enhancing the moth catches. The present results have shown the scope to enhance the impact potential of the improved Delta trap designs in monitoring and mass-trapping of YSB. The need for future population ecology R&D in linking the use of such improved Delta trap versions to fine-tuning the local action thresholds which are based on trap catches by relating to trapping efficiency as a factor is indicated.