Population dynamics of insect pests and their natural enemies in rice seed bed ecosystem (original) (raw)
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Population dynamics of insect pests in rice ecosystem
Indian Journal Of Entomology, 2021
Investigations on major insect pests in rice was carried out at the Agricultural Research Farm, Banaras Hindu University, Varanasi during kharif 2017-18 and 2018-19. Observations on Scirpophaga incertulas incidence revealed that deadhearts and white ears were observed to be maximum during 1 st week of October (40 th SMW) and 3 rd week of November (47 th SMW), respectively. Likewise, Cnaphalocrocis medinalis was observed during 1 st week of August (31 st SMW) with maximum incidence being in the 1 st week of October (40 th SMW) with 11.39% damaged leaves/ 10 hills. Nilapravata lugens appeared from 2 nd week of August (33 rd SMW) and attained its peak in 1 st week of October (40 th SMW) as 17.33/ 10 hills. The maximum incidence of Nephotettix virescens was observed in the 4 th week of October (43 rd SMW)-15.67 insects/ 10 hills. The activity of Leptocorisa acuta commenced from 3 rd week of October (42 nd SMW) and reached its peak during 3 rd week of November (47 th SMW-14.67/ 10 sweeps in nets). Correlation analysis revealed that the rainfall and evening RH exhibited a negative impact on S. incertulas, C. medinalis, N. lugens, N. virescens and L. acuta; minimum and maximum temperature, and morning RH, showed both positive and a negative impact on these insect pests of rice.
Paradigm shift of insect pests in rice ecosystem and their management strategy
Oryza, 2018
Insect population has changed both spatially and temporally over the period of time in a crop like rice. In the present study, data from the year 1965 to 2017 shows considerable increase of insect pests to 21 numbers. Their spread to large rice areas has been worked out which is a matter of concern, particularly Brown Planthopper (BPH), which has invaded all rice growing areas of the country. Present article focuses on more frequent occurrence of pests in different years related to the extent of damage incurred, which will be the principal concern of applied entomologists and farmers. Insects are classified as pests based not solely on numbers but on socioeconomic impact and on biological tolerance of the host to pest attack. In the present study, emphasis is placed upon host plant resistance to pests, proper monit oring and developing location-specific IPM packages for management of rice insect pests based on their initial populations and the processes by which they change to endemic form.
Journal of entomology and zoology studies, 2017
Fixed plot survey carried out during Kharif season (August to December) 2013 for insect pests and natural enemies complex of paddy ecosystem in different location of Cauvery command areas of Mandya district (nearby Vishveshvaraiah canal farm, Mandya). Among the pests, yellow stem borer, plant hoppers, gall midge and leaf folder were very severe and in case of predators, mirids and spiders were most important natural enemies. The average yield loss in rice has been estimated 21-51 %. The population of yellow stem borer was significantly positively correlated to Hymenopterans, Odonata and Staphylinids, whereas BPH is positively correlated with mirids (r=+0.770**), spider spider (r=+440*), odonatan (r=+0.700**), coccinellids (r=+0.476*), carabids (r=+0.779**) and cicindelids (r=+0.417*). In the same way white backed plant hopper, skipper, caseworm, hispa, blue beetle & grass hopper recorded positive significant and positive non-significant with the predators and parasitoids.
The relative abundance of major insect pests and natural enemies were studied at three different growth stages in seven high yielding varieties, Ranjit, Ranjit Sub-1, Bahadur, Bahadur Sub-1, Gitesh, Swarna Sub-1 and Shraboni in kharif and rabi season at Titabar, Assam during 2020–2022. White stem borer (47.49%) was the most predominantly abundant species followed by yellow stem borer (41.97%) among seven major insect pest species e.g., leaf folder, gall midge, caseworm, whorl maggot and gundhi bug in kharif season. But, yellow stem borer (48.69%) was abundantly observed followed by white stem borer (40.63%) among all major insect pests during rabi season. Both the species of stem borer gradually increased and reached peak due to availability of enough food at reproductive stage and decreased in the ripening stage in both the season comparatively higher in rabi season Leaf folder was the most abundant leaf feeder and its population abundance was higher in Shraboni (9.89%) followed by...
Impact of Recommended Integrated Pest Management Practices for Rice Insect in Bangladesh
Bangladesh Rice Journal, 2015
Integrated Pest Management (IPM), developed by the Bangladesh Rice Research Institute (BRRI) for management of rice insect pests, was demonstrated and validated through intensive investigation in farmer's fields of Pirganj and Taraganj in Rangpur district during 2012-2014 in two T. Aman and Boro seasons. A portion of each farmer's field kept under the respective farmers' supervision without any intervention, which was treated as control treatment (T4). The other portion was managed with three treatment combinations ie, T1=Prophylactic use of insecticide, T2=Perching + sweeping + need based insecticide application and T3=Perching only. BRRI dhan52 and BRRI dhan58 were used in Aman and Boro seasons respectively. RCB design was followed with eight replications for data analysis. The insect infestation was monitored fortnightly by visual counting from 20 hills and also 20 complete sweeps. The insect infestation, yield and yield contributing characteristics were analysed by one way analysis of variance by Tukeys' post hoc test. The objective of this studies were to validate and demonstrate the IPM techniques in farmers' field. Yellow stem borer, rice leaf roller, long horned cricket, grasshopper, green leafhopper, brown planthopper, white-backed planthopper and gall midge were found as pests in both the locations. However, insect infestation was below the economic threshold level (ETL). No significant differences were observed for insect infestation among the treatments. Natural enemies eg, spider, ladybird beetle, dragon fly, damsel fly, carabid beetle and staphylinid beetle were noticed in both the locations. In some seasons and also locations some natural enemies were not found particularly where indiscriminate/continuous insecticide was used. Thus, it was indicated that indiscriminate/continuous use of insecticide has the detrimental effect on the population of natural enemies. Also, refrained from insecticide application at early crop stages (30-40-day after transplanting) natural enemy populations increased, which might reduce insect population below the ETL. Significantly lower yield was observed at farmers managed fields in both the locations. Therefore, it was found that indiscriminate/continuous use of insecticide had no effect on yield and yield contributing characters of rice, when insect infestation below the ETL. So, farmers could avoid continuous/indiscriminate use of insecticide, which might ultimately save production cost and the environment from insecticidal pollution as well.
Journal of Biological Control
Bio-intensive pest management practices were compared with farmer's practices and untreated control in basmati rice at village Sahauli (Punjab). BIPM practices involved green manuring; seed treatment; alternate wetting and drying of the field; installation of pheromone traps and bird perches; augmentative releases of Trichogramma spp.; spray of Neem oil 1%. The farmer's practices comprised the applications of chemical insecticides. The mean leaffolder damage was 3.12, 1.90 and 5.41 per cent in BIPM, farmer's practice and untreated control, respectively. The dead heart incidence was 2.49 per cent in BIPM, 1.16 per cent in farmer's practice and 4.30 per cent in untreated control. Similarly, the mean incidence of white earheads was 3.31, 1.78 and 5.06 per cent in BIPM, farmer's practice and untreated control, respectively. Highest grain yield was recorded in farmer's practice fields (30.63 q/ha) followed by yield in BIPM fields (28.07 q/ha). These yields were significantly better than untreated control (25.18 q/ha).The population of natural enemies was higher in BIPM fields as compared to farmer's practiced fields.
Management Trends of Rice Insect Pests in South Asia: A Review
Reviews in Food and Agriculture, 2021
Rice is a staple food to over half of the world population. It is an economically important crop throughout South Asia. Rice in this region is susceptible to insect pests such as Planthoppers, Leafhoppers, Stem borers, Hispa and many others. Several management practices have been adopted in the region since historic times. The management practices include cultural, biological and chemical methods in addition to integrated and miscellaneous approaches. Rice farmers in the region rely heavily on the conventional cultural practices. However, the trend is shifting slowly to the chemical approaches with gradual increase in availability and affordability of synthetic insecticides. Integrated Pest Management (IPM), which focuses on sustainable crop production, has shown promising results. Modern management techniques such as genetic modification, use of digital technology, resistant cultivars, fungal entomopathogens etc. are more effective and eco-friendly. The focus at present should be t...
Agronomic Management of Insect-pests of Rice: A Sustainable Approach to Bring down Pest Population
Vigyan varta, 2023
Rice crop suffers from a number of biotic constraints out of them insect pests are a prominent one in deteriorating the yield and market value rice grains. Hence, management of the insect pests are of utmost importance to increase the productivity of rice. Various insect pests of rice include yellow stem borer, brown plant hopper, leaf folder, green leafhopper, hispa, gall midge etc. Agronomic management or cultural control refers to the control of insect pests through adoption of normal farm practices in appropriate time in such a way that insects are either eliminated or reduced in population. The agronomic management practices of rice insect pests are given briefly in this article.