Effect of elevated carbon dioxide on biology and morphometric parameters of yellow stem borer, Scirpophaga incertulas infesting rice (Oryza sativa)

An experiment was conducted at Research Farm, National Rice Research Institute, Cuttack, Odisha, India to quantify the effect of elevated carbon dioxide (CO2) concentrations on the biology and morphometric parameters of yellow stem borer (Scirpophaga incertulas, Pyralidae, Lepidoptera). Yellow stem borer is one of the major pest of rice in the whole rice growing regions of South East Asia. The effect of three carbon dioxide concentrations i.e. 410 ppm (ambient), 550 ppm and 700 ppm on the duration of the developmental period as well as morphometric parameters of each stage of the lifecycle of the pest was analysed. It was found that, there was an increase in the duration of the developmental period of each stage of life cycle as the concentration of CO2 increases. However, the life span of the adult moth was significantly lower under the elevated CO2 concentrations when compared with ambient CO2 concentration. Morphometric parameters viz., mean length, width and weight of each larval instar, pupa and adult were found to be significantly higher in elevated concentrations of CO2 as compared to ambient concentration.

Design and Development of BRRI Solar Powered Light Trap

This research intends to design, assemble and evaluate the performance of an eco-friendly solar light trap to reduce the insect population in rice fields as well as to minimize the use of harmful chemical pesticides. An AutoCAD drawing tool 2016 was used to sketch the design of solar light trap. The main component of this light trap was bulb, solar panel and battery. Design of solar panel and battery was done considering by 5W LED bulb. A total of five bulbs with different colors were selected to test the insect’s reaction by visible light. Study indicated that ultra violet-blue bulb showed the best performance compare to others based on the high percentage of insect trap (31.22%). A 20-watt solar panel and two 4.5 ah batteries of 6 volts were used to operate the solar light trap. The current, voltage, solar intensity was recorded to check overall performance of solar panel. The solar panel generated more power in April than May due to higher solar radiation in the study area. Study suggested that only 4.26 sunshine hours were required to full charge the battery. The solar light trap was operated 5.5 hour in night which was sufficient to reduce the insects in rice field. Moreover, the light sensor was showed 100% functional for ON/OFF purposes. The dominant insects like yellow stem borer (YSB), green leafhopper (GLH) were mostly observed. The average largest numbers of YSB and GLH were 900 and 600 respectively. In conclusion, the solar light trap is eco-friendly, low cost, easy and self-sufficient in term of solar energy. Finally, the newly developed light trap could be helpful for manufactures, decision makers, and engineering community as well as farmers as a best tool to protect nature in comparison to other pesticide using practices.

Population Dynamics of Rice Insect Pests through Light Trap Catches and Its Relation to Abiotic Factors in High Altitude Tribal Zone of Seethampeta in Andhra Pradesh, India

Studies were carried out at Agricultural Research Station, Seethampeta in Andhra Pradesh during the kharif season for three consecutive years starting from 2017 to 2019 on the population dynamics of insect pests occurring in paddy and also to assess the influence of weather parameters on insect pests. The insect pests observed in the light trap catches were, Yellow stem borer, Gall midge, Leaf folder, Green leafhopper, Plant hopper (BPH/WBPH) and Grasshoppers. The light trap catches of rice insect pests were recorded at weekly interval during 32nd Standard Meteorological Week (SMW) to 52nd Standard Meteorological Week (SMW) and the data were correlated with the weather parameters. The results revealed that more number of adults of Yellow stem borer were noticed during the year 2019 from 45th to 48th SMW and the correlation studies revealed that that maximum temperature, minimum and maximum relative humidities had significant positive influence and regression value of R2 (743, 638 and 726 during 2017, 2018 & 2019). The population of gall midge was negligible during the year 2017 and 2018. Whereas, in 2019 peak was notice during 38th SMW (15 No’s) maximum relative humidity has positive relation with increase in the gall midge population. Leaf folder adults were trapped more in the light traps during the year 2019 with peak catches of 11.00 No’s on 42nd SMW and were positively correlated with maximum temperature, minimum and maximum relative humidities. Similarly, leafhopper, brown leaf hopper, grass hoppers were positively correlated with the relative humidity.

Resistance of rice accessions against rice yellow stem borer, Scirpophaga incertulas (Walker) under greenhouse and field conditions

Sixteen rice accessions were screened under greenhouse condition and field condition against yellow stem borer (YSB) during 2014-15. Six wild accessions were screened against YSB under green house condition only. In green house condition, the accessions viz., Oryza minuta, O. nivara, IR 20, IET 23710 and IET 23715 recorded the score of 3 (moderately resistant) at both phases. Under field condition, the variety TKM 6 recorded score 1 (resistant) based on dead heart and white ear damage followed by IR 20, IET 23710 and IET 23715, which recorded the score of 3 (moderately resistant) for both dead heart and white ear damage. Both under field and green house condition, IR 20, IET 23710 and IET 23715 showed moderate resistance to yellow stem borer.

Performance of Trichogramma japonicum under field conditions as a function of the factitious host species used for mass rearing

Different factitious hosts were used to mass rear Trichogramma japonicum Ashmead in different parts of the globe because thorough details were lacking in both the laboratory and the field. The objective of this study was to compare, parasitoid, T. japonicum reared in different factitious hosts. Three commonly used factitious host eggs, Corcyra cephalonica (Stainton), Ephestia kuehniella Zeller and Sitotroga cerealella Olivier were tested under laboratory conditions and then in the field over a yellow stem borer, Scirpophaga incertulus (Walker) of rice. The highest parasitism by T. japonicum was observed on E. kuehniella eggs. The parasitoid’s highest emergence (88.99%) was observed on S. cerealella eggs at 24 h exposure, whereas at 48 h it was on E. kuehniella eggs (94.66%). Trichogramma japonicum females that emerged from E. kuehniella eggs were significantly long-lived. The days of oviposition by hosts and the host species were significant individually, but not their interaction. Higher proportions of flying T. japonicum were observed when reared on E. kuehniella and C. cephalonica eggs. Field results showed that T. japonicum mass-reared on E. kuehniella showed higher parasitism of its natural host, S. incertulus eggs. Hence, by considering these biological characteristics and field results, E. kuehniella could be leveraged for the mass rearing of quality parasitoids of T. japonicum in India, the Asian continent and beyond.