Efficacy of Newer Insecticides against Leaf Hopper and Whitefly Infesting Brinjal and its Effect on Coccinellids

摘要

Efficacy of six newer insecticides was tested during kharif 2010 and 2011 at the experimental farm, Indian Agricultural Research Institute, New Delhi, with seven treatments. Three sprays each of six chemicals were made as treatments: TV thiamethoxam 25WG @ 35 g a.i. ha~(-1) T2: buprofezin 25SC @ 60 g a.i. ha~(-1); T3: pymetrozine 50 WDG @ 120 g a.i. ha~(-1); T4: propargite 57 EC @ 900 g a.i. ha~(-1); T5: spiromesifen 240SC @ 150 g a.i. ha~(-1); T6: acetamiprid 20 SP @ 25 g a.i. ha1; along with T7: control. The plants were sprayed at fifteen days interval for testing the efficacy against leafhopper and whitefly and compared with control (unsprayed). The impact of these chemical sprays on coccinellid population was also recorded. Population counts of the above mentioned insects were recorded a day prior to spraying and then up to 13 days after spraying at three days interval (1,4,7,10 and 13~(th) day after spraying). During all the three sprays in kharif 2010 and 2011, thiamethoxam 25WG @ 35 g a.i. ha~(-1) recorded the lowest leafhopper population (3.32 and 3.15; 3.51 and 2.85 ; 2.67 and 2.84 per three leaves per plant during 1~(st), 2~(nd) and 3~(rd) spraying in 2010 and 2011 respectively) as against (9.51 and 10.43; 10.79 and 13.28;10.13 and 9.93 per three leaves per plant during 1~(st), 2~(nd) and 3~(rd) spraying in 2010 and 2011 respectively) in control. The whitefly population was recorded lowest from spiromesifen 240SC @ 150 g a.i. ha~(-1) treated plots in all the three sprays during kharif 2010 and 2011. The coccinellid population in all the three sprays was found to be on par with control population in treatments with buprofezin, pymetrozine, spiromesifen and propargite. The neonicotinoid group (acetamiprid and thiamethoxam) recorded the lowest population of coccinellids among the six different chemicals.