ABSTRACT

This study aimed to evaluate the effect of eleven treatments viz. mixture insecticides namely ripcord 10 EC+ imitaf 20 SL, ripcord 10 EC+ decis 2.5 EC, decis 2.5 EC+ imitaf 20 @ 1ml/L of water, sevin 85 SP+actara 25 WG @ 1.25g/L of water, voliam flexi 300 SC (thiamethoxam+chlorantraniliprole) @ 0.5ml/L of water, novastar 56 EC (bifenthrin+abamectin) @ 1ml/L of water and ripcord 10 EC, imitaf 20 SL, decis 2.5 EC     @ 1ml/L of water, sevin 85 SP @ 2g/L of water, actara 25 WG 0.5g/L of water by application 15 days interval along untreated control on the infestation level of litchi fruit borer and to find out the benefit-cost ratio for managing this pest by insecticide treatments. The results showed that the lowest fruit infestation was found in thiamethoxam+chlorantraniliprole (0.33%) followed by bifenthrin+abamectin(1.60%), sevin+actara (1.68%); imitaf (1.84%), actara (3.52%) and decis (3.85%) which was significantly difference from all other treatments and increased fresh fruit (52.83%), (52.23%) (52.19%) (52.11%) (51.27%) (51.11%), respectively over control. But, the highest benefit was obtained from the treated tree with decis (11.64:1) in single and mix formulation insecticide bifenthrin+abamectin (10.83:1) which was profitable to manage LFB. The maximum fruit infestation was observed (9.53%) in ripcord+decis and single ripcord (6.69%) in the treated fruits.The pre-formulation mixture of bifenthrin+abamectin (novastar 56 EC) was the most effective and decis 2.5 EC (deltamethrin) was the cost-effective approach at the rate of 1ml per liter water which can be used for controlling LFB.

Key words: Conopomorpha sinensis, Litchi chinensis, fruit infestation, insecticides.