Population dynamics and management of insect pests of rice and their natural enemies in different rice cultivation systems in Bihar
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Date
2020
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DRPCAU, Pusa
Abstract
Investigations were carried out to record the population dyanamics and
Management of Insect Pests of Rice and their Natural Enemies in different Rice
Cultivation Systems in rice CV Rajendra Bhagwati in Pusa, Bihar. Field experiments were
conducted at the Research Farm, RPCAU, Pusa and in the Laboratory, Department of
Entomology, RPCAU, Pusa during Kharif, 2016 and 2017. Results pertaining to different
aspects of the study viz. to study the dynamics of pest species composition of rice stem
borers, to ascertain the population dynamics and management of stem borers, leaf folder
and Gundhi bug, to study the population dynamics of different natural enemies, to assess
the efficacy of different insecticides against different insect pests and its effect on different
natural enemies have been abstracted below:
All the four species of stem borer of rice viz. yellow stem borer, Scirpophaga
incertulas (Walker), pink stem borer, Sesamia inferens (Walker), white stem borer,
Scirpophaga innotata (Walker) and dark headed striped borer, Chilo polychrysus
(Meyrick) were prevalent during the crop season. However, yellow stem borer was found
to be dominant over other species of stem borer and showed consistency with higher
population in the entire four cultivation system viz. transplanting (92.70 to 93.50%), drum
seeded (91.22 to 92.10%), direct seeded (94.00 to 95.17%) and SRI (89.10 to 90.00%)
(System of Rice Intensification) during Kharif, 2016 and 2017, respectively.
Highest population of leaf folder and gundhi bug were found in direct seeded
followed by transplanting, drum seeded and SRI cultivation system with 8.73 & 17.39,
8.48 & 15.20, 6.51 & 14.63 and 6.12 & 13.61/ five sweeping net, respectively. (Plooed
mean Kharif 2016 & 2017). Among all cultivation systems highest spider population were
found in SRI with 13.40 followed by transplanting with 12.21 numbers of Spiders/ sq m.
Lowest spider population was found in Direct seeded with 9.45 followed by Drum seeded
with 10.82 numbers of Spiders/sq m. Almost similarly highest population of ladybird
beetle, ground beetle and mirid bug were recorded in SRI with 16.01, 4.04 and 4.10
followed by Drum seeded with 14.26, 3.63 and 3.84; Transplanting with 13.34, 3.23 and
3.63 and direct seeded with 12.37, 3.12, 3.39 numbers of /sq m, respectively. Highest
numbers of population of dragonfly and damselfly were recorded in SRI with 9.10 and
4.49 followed by Transplanting with 8.53 and 4.41 Drum seeded with 8.17 and 3.86 and
7.65 and 3.69 numbers/five sweeping nets, respectively.
Seasonal incidence of Yellow stem borer (1.00 to 16.28 %, 1.71 to 17.02 %, 2.11 to
17.86 % and 2.71 to 14.85 %), Pink stem borer (1.33 to 5.91%, 1.05 to 6.52%, 1.54 to
6.70% and 0.80 to 5.43%), White stem borer (1.11 to 5.31%, 1.00 to 5.46%, 1.45 to 6.39%
and 1.44 to 5.44 %) and Dard headed stem borer (0.53 to 5.42%, 0.29 to 5.74 %, 1.05 to
5.96% and 0.69 to 5.12%) were observed in transplanting, drum seeded, direct seeded and
SRI cultivation system, respectively, during 4th week of July (30th SMW) to 1st week
October (40th SMW). The prevailing measured weather parameters; maximum and
minimum temperatures range of 31.80 0C to 33.80 and 25.9 to 26.50C, maximum and
minimum relative humidities 86.00 to 90.50 per cent 68.00 to 74.50 per cent and weekly
rainfall 0.0 to 152.2 mm were found during infestation period.
Seasonal incidences of Rice stem borers (YSB, PSB, WSB, and DHSB) in different
rice cultivation system was found in the ranges of 0.56 to 20.60 percent, 1.10 to 16.66
percent and 1.35 to 21.76 percent in transplanting, drum seeded, and direct seeded
cultivation system, respectively, during 4th week of September (39th SMW) to 2nd week
November (46th SMW). However, in SRI cultivation system white earhead symptom was
found in the range of 0.07 to 16.78 per cent during 3rd week of September (38th SMW) to
1st week November (45th SMW). The prevailing measured weather parameters; maximum
and minimum temperatures range of 31.80 0C to 33.80 and 25.9 to 26.50C, maximum and
minimum relative humidities 86.00 to 90.50 per cent 68.00 to 74.50 per cent and weekly
rainfall 0.0 to 152.2 mm were found during infestation period.
Rice leaf folder incidence in different rice cultivation system was found in the
ranges of 1.86 to 18.65 percent, 1.10 to 18.07 percent, 1.14 to 20.95 percent and 0.18 to
16.56 percent in transplanting, drum seeded, direct seeded and SRI cultivation system,
respectively during 4th week of July (30th SMW) to 4th week October (44th SMW). The
prevailing measured weather parameters; maximum and minimum temperatures range of
31.80 0C to 33.80 and 25.9 to 26.50C, maximum, and minimum relative humidities 86.00
to 90.50 per cent and 68.00 to 74.50 per cent and weekly rainfall 0.0 to 152.2 mm were
found during infestation period. Seasonal incidence of rice gundhi bug in different rice
cultivation were found in the ranges of 0.14 to 3.56; 0.07 to 4.05;0.15 to 4.97 and 0.30 to
3.18 in transplanting, drum seeded, direct seeded and SRI cultivation system, respectively,
during 1st week of August (31st SMW) to 4th week October (43th SMW). The prevailing
measured weather parameters: maximum and minimum temperatures range of 31.80 0C to
33.80 and 25.9 to 26.50C, maximum, and minimum relative humidities 86.00 to 90.50 per
cent 68.00 to 74.50 per cent and weekly rainfall 0.0 to 152.2 mm were found during
infestation period.
All the treatments were found significantly superior over untreated control in
respect to per cent mean Deadheart (DH) and White earhead (WEH). Among the all
treatments Imidacloprid 17.8SL (4.20%, 1.37%, 1.33% and 1.62% DH) and Thiamethoxam
25WG (4.94%, 1.69%, 1.51% and DH) were found most effective in reducing percent
deadheart caused by Yellow stem borer, Pink stem borer, White stem borer and Dark
headed stem borer, respectively over the standard check Monocrotophos 36SL (6.73%,
1.95%, 1.68%, and 2.18% DH). However, among the all treatments Imidacloprid 17.8SL
(8.58% WEH) and Thiamethoxam 25WG (9.33%WEH) were found most effective in
reducing percent white earhead over the standard check Monocrotophos 36SL (12.86%
WEH). All the treatments were found significantly superior over untreated control in
respect to per cent mean damaged leaf (DL) infestation caused by rice leaf folder. Among
the all treatments, Acephate 75SP (6.80% DL) followed by Imidacloprid 17.8SL (7.59%
DL), Thiamethoxam 25WG (8.32% DL) were found most effective in reducing percent
damaged leaf over the standard check Monocrotophos 36SL (11.18% DL). All the
treatments were found significantly superior over untreated control in respect to number of
gundi bug. Among the all treatments Imidacloprid 17.8SL (0.64/hill) and Thiamethoxam
25WG (0.87/hill) were found most effective in reducing Gundhi bug population over the
standard check Monocrotophos 36SL (1.08/hill).
Mean yield production was varied widely from 39.22 to 49.35q/ha with maximum
and minimum being in treatment of insecticide component and untreated control,
respectively. Highest yield with 49.35 q/ha and 47.78 q/ha were recorded from
Imidacloprid 17.8SL and Thiamethoxam 25WG treated plots. Among all treatments
Buprofezin 25SC Dinotefuron 20SG Monocrotophos 36SL Thiamethoxam 25WG
Imidacloprid 17.8SL and Acephate 75SP were recorded maximum survived spider,
ladybird beetle, dragonfly, damselfly, ground beetle and mirid bug population over
standard check Monocrotophos 36SL.