STUDIES ON INCIDENCE OF BROWN PLANTHOPPER, Nilaparvata lugens (Stal.) (Delphacidae: Hemiptera) IN DIRECT SEEDED RICE AND ITS MANAGEMENT
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Date
2022-08-10
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guntur
Abstract
“Studies on incidence of Brown Planthopper, Nilaparvata lugens (Stal.) (Delphacidae: Hemiptera) in direct seeded rice and its management” were conducted with an aim to know the incidence of BPH and its natural enemies in rice ecosystems at farmers’ fields of Guntur district and to study the efficacy of novel insecticides in combination with neem products against BPH and its natural enemies at Agricultural College Farm, Bapatla during kharif, 2020.
Survey was conducted to record the incidence of BPH, WBPH and natural enemies like mirid bugs, spiders and coccinellids at active tillering, panicle initiation (PI) and harvesting stages of both Direct Seeded Rice (DSR) and Puddled Transplanted Rice (PTR) fields in five mandals viz., Bapatla, Ponnur, Amarthaluru, Karlapalem and Pittalavanipalem of Guntur district during kharif, 2020.
The survey data indicated that the mean population of BPH per hill was statistically lower in DSR (4.70, 9.15 & 1.15) when compared to PTR (6.10, 11.22 & 1.57) respectively at active tillering, PI and harvesting stages. Same trend was observed in WBPH population also with statistically lower population in DSR (2.28, 4.15 & 0.82) when compared to PTR (3.15, 5.43 & 1.01) respectively at active tillering, PI and harvesting stages of crop growth. Thus, the mean population of both BPH and WBPH was highest during PI stage with a mean population of 11.22 and 5.43 hoppers per hill respectively in PTR.
The mean population of mirid bugs was statistically lower in DSR (3.05, 4.71 & 1.19) when compared to PTR (4.32, 5.66 & 1.40) respectively at active tillering, PI and harvesting stages. The mean population of spiders was statistically lower in DSR (0.61, 1.23 & 1.13) when compared to PTR (0.75, 1.8 & 1.31) respectively at active tillering, PI and harvesting stages. The mean population of cocccinellids was statistically lower in DSR (0.44, 0.86 & 0.90) when compared to PTR (0.54, 1.08 & 1.10) respectively at active tillering, PI and harvesting stages of crop growth.
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The data on management of BPH and WBPH with certain novel insecticides revealed that all the insecticide treatments were found superior over untreated control. Among the different insecticidal treatments on BPH after the two sprays revealed that triflumezopyrim 10.6 SC @ 25 g a.i. ha-1 was found to be the best treatment with 64.40 per cent reduction over untreated control, followed by dinotefuran 20 SG @ 40 g a.i. ha-1 (57.97%) and pymetrozine 50 WG @ 150 g a.i. ha-1 (55.62%). The efficacy of different insecticidal treatments on WBPH after the two sprays followed the same trend as that of BPH, with triflumezopyrim 10.6 SC @ 25 g a.i. ha-1 as the best treatment with 68.29 per cent reduction over untreated control, followed by dinotefuran 20 SG @ 40 g a.i. ha-1 (62.48%) and pymetrozine 50 WG @ 150 g a.i. ha-1 (60.85%).
The data on effect of insecticide treatments on mirid bugs revealed that neem formulation 1500ppm @ 5 ml l-1 recorded highest population of green mirid bugs (6.50/hill) and found to be the safest treatment against green mirid bugs. Other treatments pymetrozine + neem formulation @ 75 g a.i ha-1 + 5 ml l-1 and triflumezopyrim + neem formulation @ 12.5 g a.i. ha-1 + 5 ml l-1 recorded 4.68, 4.60 mirid bugs/hill and were on par with neem formulation 1500ppm. The data on spider population revealed that neem formulation 1500ppm @ 5 ml l-1 was found to be the safest treatment with 8.86 spiders/10 hills. All the other treatments had moderate influence on spider population and were on par with each other.
The grain yield was highest in triflumezopyrim 10.6 SC @ 25 g a.i. ha-1 (4974 kg ha-1) treated plots with 63.67 per cent increase in yield over untreated control followed by dinotefuran 20 SG @ 40 g a.i. ha-1 (4720 kg ha-1) and pymetrozine 50 WG @ 150 g a.i. ha-1 (4619 kg ha-1) with 55.33 & 51.99 per cent increase in yield over untreated control, respectively.
The highest ICB ratio was recorded with dinotefuran 20 SG (1:4.40) followed by pymetrozine 50 WG (1:4.17), triflumezopyrim 10.6 SC (1:3.78), dinotefuran + neem formulation (1:2.27), pymetrozine + neem formulation (1:2.18), neem formulation 1500ppm (1:1.61) and triflumezopyrim + neem formulation (1:1.53).
Description
STUDIES ON INCIDENCE OF BROWN PLANTHOPPER, Nilaparvata lugens (Stal.) (Delphacidae: Hemiptera) IN DIRECT SEEDED RICE AND ITS MANAGEMENT