A new sampling technique involving yellow sticky traps for monitoring of thrips infesting different crops

Yellow sticky traps were used to monitor the activity of seven different species of thrips infesting cotton, sunflower, groundnut and soybean in the gardenland ecosystem and brinjal, okra, tomato, chillies, onion and sweet potato in the orchard ecosystem of the Tamil Nadu Agricultural University, Coimbatore during August 1991-February 1992. The cylindrical aluminium traps painted with bright highways yellow colour were erected at a height of 30 cm and smeared with castor oil. Observations commenced from 20 days after sowing/transplanting and continued up to senescent stage of the crop. Trap catches revealed that mean number of thrips/trap/week were maximum on sunflower (915.34) followed by onion (638.98) and soybean (586.06). The next in the order were brinjal (452.05) > okra (417.83) > cotton (407.17) > groundnut (374.44) > tomato (371.76). Minimum catches were recorded on sweet potato (253.21) > chillies (240.21), and were at par with cotton, groundnut and tomato.