Activity and control of citrus thrips, Scirtothrips citri (Moulton) on kinnow

Studies conducted during 2003–2005 on the activity of citrus thrips, Scirtothrips citri (Moulton) on flower buds/flowers of Kinnow plants showed that the pest started appearing in first week of March with the initiation of flowering and caused damage to petals, stamens and basal part of the ovary. Its attack continued upto third week of April. The population increased progressively and reached at peak (14.7 nymphs and adults/flower) in 4th week of March while no thrips population was observed in 4th week of April. Thrips caused maximum scarring (64.7%) at the distal end of fruit followed by proximal end (27.6%) and central portion (7.7%). Evaluation of insecticides at different concentrations revealed that three applications at pre-flowering, flowering and pea stage of fen valerate and cypermethrin (each 0.02%); quinalphos, ethion, endosulfan, triazophos and oxydemeton methyl (each 0.05%) were effective (100% thrips mortality) in reducing the fruit scarring from 34.7 per cent in control to 0–0.9 per cent in these treatments. However, spraying of ail these insecticides at pea stage had 29.6 to 34.2 per cent scarred fruits while two sprays at flowering and pea stage resulted in 0.6–5.9 per cent fruit scarring.