Yellow and Blue sticky traps

A number of insect species are attracted to yellow colour. If a yellow coloured card is placed in a crop field, these flying insects will attempt to land on it. Covering the surface with non drying glue or with grease immobilizes and kills the insects. This forms the basic principle of yellow sticky traps.

Yellow sticky cards trap the adult stages of flying insects such as flower thrips, whiteflies, leaf miners, flea beetles and winged aphids.  However, mites, mealy bugs, scales, and wingless aphids do not fly and will not be caught on the sticky cards. Also, immature stages of thrips, and whiteflies will not be caught on the cards.

Yellow and blue coloured sticky cards are commercially available. Blue cards are more useful for trapping thrips.

Sticky cards can be made in any dimensions. The commonly available size is 3 by 5 inch.  Use at least 3 to 4 cards per 1000 sq. ft. or a minimum of one card per 1000 sq. ft. Place additional cards near doors, vents, and over insect-sensitive plant species or cultivars.  The cards should be placed one foot above the crop canopy.

An empty tin, board, plate or a wall painted yellow and smeared with castor oil will also serve the purpose. The adults of sucking pests that are attracted by the bright yellow colour get trapped in the oil smear. The trapped insects should be wiped off from the cards periodically and oil should be applied again.