EVALUATION OF THE EFFECT OF ELEVATED CO2 ON BIOEFFICACY OF BUPROFEZIN INSECTICIDE AGAINST BROWN PLANT HOPPER,  Nilaparvata lugens (STÅL)

The effect of elevated CO2 (570±25ppm) on the brown plant hopper (BPH) population, rice yield parameters, and efficacy of buprofezin (0.05%) in terms of spray volume was studied in an open top chamber (OTCs) during rainy season 2017 and 2018. The pest population was observed to be higher during 2017 compared to the rainy season of 2018. Under elevated CO2, rice plants had more vegetative tillers (18%) and reproductive tillers (22.1%), but there was a decrease in 1000-seed weight (11.2%), seed number per panicle (3.91%), and grain yield (18.8%) in comparison to ambient CO2 grown rice plants. The spray volumes of 700, 600, 500, and 400 l/ha each caused higher BPH mortality under ambient CO2 compared to elevated CO2. A spray volume of 500 l/ha did not prove as effective under elevated CO2 as under ambient CO2. Lower efficacy of spray volume of 500 l/ha under elevated CO2 could be ascribed to higher canopy size under elevated CO2 due to higher tillering. Increased crop canopy size under elevated CO2 may thus require higher spray volume to ensure proper coverage. Results of the study suggested a need to revise spray volume recommendations to facilitate effective management of BPH under climate change.

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Effects of elevated CO2 on resistant and susceptible rice cultivar and its primary host, brown plant hopper (BPH), Nilaparvata lugens (Stal)

10.21203/rs.3.rs-118055/v1 ◽

2020 ◽

Author(s):

Sengottayan Senthil-Nathan

Keyword(s):

Elevated Co2 ◽

Insect Pests ◽

Rice Cultivar ◽

Nilaparvata Lugens ◽

Carbon Accumulation ◽

Rice Cultivars ◽

Ambient Conditions ◽

Primary Host ◽

Nilaparvata Lugens Stål ◽

Brown Plant Hopper

Abstract Elevated CO2 has positive response on plant growth and negative response on insect pests. As a contemplation, the feeding pattern of the brown plant hopper, Nilaparvata lugens Stål on susceptible and resistant rice cultivars and their growth rates exposed to elevated CO2 conditions were analyzed. The elevated CO2 treatment showed significant differences in percentage of emergence and rice biomass that were consistent across the rice cultivars, when compared to the ambient conditions. Similarly, increase in carbon and nitrogen ratio of leaves and alterations in defensive peroxidase enzyme levels were observed, but was non-linear among the cultivars tested. Lower survivorship and nutritional indices of N. lugens were observed in conditions of elevated CO2 levels over ambient conditions. Results were nonlinear in manner. We conclude that the plant carbon accumulation increased due to elevated CO2, causing physiological changes that decreased nitrogen content. Similarly, elevated CO2 increased insect feeding, but did not alter other variables such as their biology or reproduction.

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Seasonal variation in population and biochemical contents of brown planthopper, Nilaparvata lugens (Stål)

Journal of Environmental Biology ◽

10.22438/jeb/43/1/mrn-1983 ◽

2022 ◽

Vol 43 (1) ◽

pp. 52-58

Author(s):

S. Narayana ◽

◽

S. Chander ◽

S. Doddachowdappa ◽

S. Sabtharishi ◽

...

Keyword(s):

Population Dynamics ◽

Rainy Season ◽

Brown Planthopper ◽

Chemical Compounds ◽

Nilaparvata Lugens ◽

Water Soluble ◽

Soluble Carbohydrates ◽

Water Soluble Carbohydrates ◽

Nilaparvata Lugens Stål ◽

Brown Plant Hopper

Aim: The present study was undertaken on population dynamics and estimation of protein, water-soluble carbohydrates and glycogen contents in the brown planthopper, Nilaparvata lugens to explore their migratory behaviour. Methodology: Brown planthopper populations were monitored and collected using sweep nets from 23rd standard meteorological week (SMW) to 47th SMW during 2017 and 2018 rainy seasons to understand population dynamics of the pest. The protein, water-soluble carbohydrates and glycogen contents were estimated from the pest samples collected during 36th to 44th SMW in 2017 and 2018 rainy seasons. Results: Brown planthopper population were not observed in rice farm during 23rd SMW to 28th SMW during two years of study. However, macropterous form of the pest first appeared in the farm during 29th SMW and peaked during 43rd SMW. Thereafter, population declined and disappeared after 47th SMW during both the years. Water-soluble carbohydrates and glycogen contents varied significantly different weeks which remained low during 36th-39th SMW, however, increased gradually towards the end of the rainy season 2017 and 2018. On the other hand, protein content significantly varied among different weeks unlike the trend of water-soluble carbohydrates and glycogen. Interpretation: The study revealed the absence of brown plant hopper during summer season preceding rainy season, and the accumulation of bio-chemical compounds towards the end of rainy season under Delhi environment is perhaps suggestive of migration of the pest from unknown areas during rainy season to Delhi and likely preparedness of the pest for emigration to safer areas from Delhi, respectively.

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