Pest Scenario Research Articles

Pesticide Usage Pattern by Paddy Growers in Palnadu District of Andhra Pradesh

Background: Over the years, pesticides have been crucial in ensuring food security since novel compounds have been produced in response to changing pest scenarios, environmental concerns and food safety regulations. Methods: The study was carried out on pesticide usage pattern followed in paddy fields of Palnadu district, Andhra Pradesh during rabi 2020-21 in 15 villages of five mandals. Fortnightly observations on pesticide usage pattern in individual farmer field was collected using a questionnaire prepared in the regional language (Telugu). Result: Farmers in the Palnadu district during rabi 2020-21 applied 345 pesticides in 177 applications/sprayings, with an average of 4.32 sprayings/applications per farmer and 8.41 pesticides in each field during the crop season, while ZBNF farmers have not used any pesticide. The commonly used pesticides in the area were acephate, flubendiamide and propineb, out of a total of 34 pesticides, 17 insecticides; 12 fungicides; 4 herbicides and one bio-chemical product were used by the farmers.

Shifting Pest Paradigms in Indian Crops: A Comprehensive Review of Emerging Threats

Sustainable crop production directly relates to the insect repercussions in future climates. In recent times, it has been essential to look over the changes in the pest scenario as the categories of pests may shift. Such deviations in the pest status are due to multiple factors viz., increased temperature, rise in Co2 levels, etc. This is well-witnessed in a wide array of crops. Changes in these factors favour the pest species depending on their ecology. Monitoring the climate and pest population is vital for understanding the effect of climate change on insect pests. Therefore, the forecasting and prediction models must be adjusted considering the evolving circumstances. This review examines these changes in key crops, including pearl millet, maize, okra, cotton, tomato, chilli, cassava, mango and coconut. Significant pest shifts include the replacement of stem borer and shoot fly by fall armyworm in maize and the rise of sucking pests in Bt cotton. New invasive pests such as Tuta absoluta in tomato and Thrips parvispinus in chilly underscore the shifting pest landscape. The review highlights the importance of monitoring pest populations and advocates for integrated pest management (IPM) strategies, the development of resistant varieties and conservation of natural enemies to mitigate economic losses.

Carbon Emissions Effect on Vendor-Managed Inventory System Considering Displaced Re-Start-Up Production Time

Background: The classical mathematical formulation of the vendor-managed inventory (VMI) model assumes an infinite planning horizon, and consequently, the solution derived ignored the impact of the first cycle. The classical formulation is associated with another implicit assumption that input parameters remain static indefinitely. Methods: This paper develops two mathematical models for VMI for a joint economic lot-sizing (JELS) policy. Each model considers investment in green production, energy used for keeping items in storage, and carbon emissions from production, storage, and transportation activities under the carbon cap-and-trade policy. The first model underlies the first cycle, while the second underlies subsequent cycles. Results: The re-start-up production time for subsequent cycles commences only at the time required to produce and replenish the first lot, which implies further cost reduction. Mathematical formulations are perceived as important both for academics and practitioners. For example, the base model of the first cycle (subsequent cycles) generates an optimal produced quantity with 18.42% (4.35%) less total system cost when compared with the pest scenario in favor of the existing literature. Moreover, such a percentage of total system cost reduction increases as the production rate increases. Further, the proposed models not only produce better results but also offer the opportunity to adjust the input parameters for subsequent cycles, where each cycle is independent from the previous one. Conclusions: The emissions generated by the system are very much related to the demand rate and the amount of investment in green production. Illustrative examples, special cases, model overview, and managerial insights are given. The discussion related to the contribution of the proposed model, the concluding remarks, and further research are also provided. The proposed model rectifies the base model adopted by the existing literature, which can be further extended to be implemented in several interesting further inquiries related to JELS inventory mathematical modeling.

Pest scenario of Helicoverpa armigera (Hub.) on pigeonpea during future climate change periods under RCP based projections in India

Gram pod borer, Helicoverpa armigera (Hub.) is the major insect pest of pigeonpea and prediction of number of generations (no. of gen.) and generation time (gen. time) using growing degree days (GDD) approach during three future climate change periods viz., Near (NP), Distant (DP) and Far Distant (FDP) periods at eleven major pigeonpea growing locations of India was attempted. Multi-model ensemble of Maximum (Tmax) and Minimum (Tmin) temperature data of four Representative Concentration Pathways viz., RCP 2.6, 4.5, 6.0 and 8.5 of Coupled Model Inter comparison Project 5 (CMIP5) models was adopted here. The increase in projected Tmax and Tmin are significant during 3 climate change periods (CCPs) viz., the NP, DP and FDP over base line (BL) period under four RCP scenarios at all locations and would be higher (4.7–5.1 °C) in RCP 8.5 and in FDP. More number of annual (10–17) and seasonal (5–8) gens. are expected to occur with greater percent increase in FDP (8 to 38%) over base line followed by DP (7 to 22%) and NP (5to 10%) periods with shortened annual gen. time (4 to 27%) across 4 RCPs. The reduction of crop duration was substantial in short, medium and long duration pigeonpeas at all locations across 4 RCPs and 3 CCPs. The seasonal no.of gen. is expected to increase (5 to 35%) with shortened gen. time (4 to 26%) even with reduced crop duration across DP and FDP climate periods of 6.0 and 8.5 RCPs in LD pigeonpea. More no. of gen. of H. armigera with reduced gen. time are expected to occur at Ludhiana, Coimbatore, Mohanpur, Warangal and Akola locations over BL period in 4 RCPs when normal duration of pigeonpeas is considered. Geographical location (66 to 72%), climate period (11 to 19%), RCPs (5–7%) and their interaction (0.04–1%) is vital and together explained more than 90% of the total variation in future pest scenario. The findings indicate that the incidence of H. armigera would be higher on pigeonpea during ensuing CCPs in India under global warming context.

Screening of Hybrid Varieties of Tomato Crop against American Serpentine Leaf Miner, (Liriomyza trifolii, Burgess) in Lucknow District of Uttar Pradesh, India

Tomato is a major cash crop of farmers of central plain of Uttar Pradesh. Injudicious use of chemicals invited too many number of insect pests. Among them sucking insect problems were very serious in comparison to biting and chewing insects because these insects developed resistance and insecticides. So, in last five years pest scenario had changed. Some new insects were seen on crops. In which, American serpentine leaf minor in one of them. Their incidence increasing very rapidly in different crops like tomato, vegetable pea and cucurbitaceous crops etc. Tomato crop was more susceptible for leaf miner. Due to which screening of popular tomato varieties were urgently needed. On that basis this study were carried out on ten popular hybrid varieties. The field incidence of the serpentine leaf miner, L. trifolii (Burgess) was severe during the fruiting stage of the crop. Infestation was higher on lower surface of leaf in comparisons of upper surface. On the basis of cumulative susceptibility index test varieties all varieties viz. Pusa Rohini, Pusa Uphar, Arka Saurabh, Naveen-2000, N-815, Arka Vardan, Pusa Sadabahar, Arka Vishal, N-2535 and ArkaVardan were found to be resistant/less susceptible. There were no significant correlation found among leaf miner incidence and yield of crop. All tested hybrid varieties performed better in Lucknow district of Uttar Pradesh.

Observations on the herbivore diversity in a managed tea plantation and population dynamics of major insect pest in tea with regional weather

Globally, the pattern of incidence of insect pest complex has been changing in all agroecosystem due to climate change and variability. It is essential to know the incidence pattern of insect pest complex in tea for adopting successful management practice. An investigation was carried out to know the present incidence pest scenario of tea at Assam during March 2019 to Feb 2020. The results show the presence of four mite species belonging to single order and 4 families, and a total of 33 insect species belonging to 7 orders and 27 families. Among them red spider mite, tea mosquito bug, whitefly, leafhopper complex and thrips were recorded as important sucking pests. Leaf roller, tea tortrix, and flush worm were recorded as significant chewing pests. Observation shows that the tea whitefly, leaf hopper, thrips, leaf roller and flush worm has become a serious threat to the tea cultivation. The population dynamics of red spider mite and tea mosquito bug recorded a maximum incidence of 30.27 mites/ leaf and 27.17 infested flush/ bush respectively, during the month of November. Both insects were negatively regulated by maximum temperature and rainfall however relative humidity positively influenced population dynamics, as revealed by the correlation coefficient. This study paves way for the development of a new plant protection module to manage the emerging insect pests in tea plantation.

Insect pest scenario in Uttarakhand Himalayas, India, under changing climatic conditions.

The Himalayan mountains are early indicators of climate change, wherein slight changes in climate can lead to a drastic variation in faunal diversity, distribution, invasion of fauna into higher altitudes, rapid population growth, shortening of life cycle and increased number of overwintering species. The insects best represent the faunal diversity. In recent years, due to variation in pattern of rainfall and temperature regimes, several insect pests have moved northwards and are posing great threat to hill agriculture. Few among them are greenhouse whiteflies, thrips and mites in protected cultivation system; blister beetles on flowers of cereals, pulses and oilseeds; invasive insect pests like fall armyworm of maize and tomato pin worm and sporadic pests like grasshoppers that are reaching a status of major key pest in various crops. Keeping in mind the phenomenon of climate change and associated changes in pest population, the present article focuses on emerging insect pest problems in cereals, millets, pulses, oilseeds and vegetables of Indian Himalayas, along with their changing population density with respect to different climatic parameters, the per cent increase in the pest damage over the years and their potential of gaining the status of major pests in near future and causing huge economic losses to hill agriculture.

Effect of elevated CO2 and temperature on thermal constants and lower threshold temperatures of maize aphid, Rhopalosiphum maidis (Fitch.) (Aphididae:Hemiptera) on maize, Zea mays (Linn.)


 The objective of this study was to examine the development of corn leaf aphid,Rhopalosiphum maidis Fitch (Aphididae: Hemiptera) on maize Zea mays Linnaeus at elevated and ambient concentrations of CO2 (550 and 380ppm ± 25 ppm, respectively) at six temperatures (20, 25, 27, 30, 33 and 35°C) and to estimate thermal constants and lower temperature thresholds for the forecasting models based on heat accumulation units which could be developed for use in forecasting. The duration of different growth stages of R.maidis were reduced with an increase of temperature from 20°C to 35°C under both ambient and elevated CO2 conditions. The lower development threshold for first nymphal instar,second nymphal instar, third nymphal instar, fourth nymphal instar, adult duration and total development period required 10.1, 5.04, 13.42, 26.96, 10.9, 23.22 and 20.20°C under eCO2 whereas it was 13.32, 9.41, 19.13, 30.48, 16.38, 22.88 and 20.89°C under aCO2 conditions,respectively. The mean lower temperature threshold for nymph was slightly higher (16.38°C) at aCO2 compared to that of eCO2 (10.90°C) whereas for adult the mean lower temperature threshold was slightly higher (23.22°C) at eCO2 compared to that of aCO2 (22.88°C). The thermal requirement of R. maidis from first nymphal instar to adult (total development period) was found to be 100.00 degree days (DD) under eCO2 conditions as against 111.11degree days under aCO2 conditions. These estimated temperature thresholds and thermal constant can predict the pest scenarios and population dynamics of R. maidis.

Survey on major insect pests of groundnut in Southern Telangana zone

Survey on major insect pests of groundnut was carried out in Southern Telangana Zone comprising of the three districts viz., Mahabubnagar, Nagarkurnool and Wanaparthy at three stages of crop growth period viz., vegetative, pod formation and maturity stages for identification of pest scenario. In all the three districts the mean percent damage per plant (14.50-18.85%) and mean no. of larva per plant (0.90-1.05) of tobacco caterpillar were comparatively higher at pod formation stage while percent infested plants were more during maturity stage (38.60-40.30%). With respect to gram caterpillar, the mean percent damage per plant (2.90-3.60%) and mean percent infested plants (12.80-18.50%) was higher at maturity stage while in case of the leaf miner mean percent mining per plant (1.75-3.10%) was more at vegetative stage while mean percent infested plants (7.80-9.50%) was greater at pod formation stage. The mean no. of sucking pests viz., leafhoppers and thrips were recorded to be higher during pod formation stage (2.37-2.47 and 3.92-4.02, respectively).

Changing concepts in crop protection - a perspective view

Crop protection has traversed a long way from the conventional approaches to more advanced modern technologies. The predominantly chemical-based approach, that has been a part of the green revolution technologies, is giving way to the integrated approach of environment friendly technologies with less and less dependence on chemical pesticides. In this context, molecular biology has played an important role in developing resistant varieties through transfer of desired genes from wild and unrelated sources using various tools such as MAS, RNAi, recombinant DNA and CRISPR gene editing systems. Emphasis is being given to develop new pesticides based on green chemistry with least impact on the environment and to use them in an integrated manner along with other control methods including biological. Decision support systems can play significant role in reducing the use of pesticides. Much attention is also given on induced resistance in crop plants through use of various biotic and abiotic agents. Focus needs to be given to redefine pest management strategies in the wake of emerging pest scenario due to climate change. This review gives a perspective account of various technologies developed in the recent past and their scope in managing agricultural pests and pathogens with minimal impact on the environment.

Pest scenario of Spodoptera litura (Fab.) on groundnut under representative concentration pathways (RCPs) based climate change scenarios.

Multi-model ensemble of Maximum (Tmax) and Minimum (Tmin) temperature data of four Representative Concentration Pathways viz., RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 of Coupled Model Intercomparison Project 5 (CMIP5) models were generated for ten major groundnut growing locations of the India to predict the number of generations of Spodoptera litura (Fab.) using Growing Degree Days approach during three future climate viz., Near (NF), Distant (DF) and Very Distant (VDF) periods and were compared over 1976-2005 baseline period (BL). Projections indicate significant increase in Tmax (0.7-4.7°C) and Tmin (0.7-5.1°C) in NF, DF and VDF periods under the four RCP scenarios at the ten groundnut growing locations. Higher percent increase of the number of generations of S. litura was predicted to occur in VDF (6-38%) over baseline, followed by DF (5-22%) and NF (4-9%) periods with reduction of generation time (5-26%) across the four RCP scenarios. Reduction of crop duration was higher (12-22 days) in long duration groundnut than in medium and short duration groundnut. Decrease in crop duration was higher in VDF (12.1-20.8 days) than DF (8.26-13.15 days) and NF (4.46-6.15 days) climate change periods under RCP 8.5 scenario. Increase in number of generations of S. litura was predicted even with altered crop duration of groundnut. Among locations, more number of generations of S. litura with reduced generation time are likely at Vridhachalam and Tirupathi locations. Geographical location (74-77%) and climate period (15-19%), together explained over 90 percent of the total variation in the number of generations and generation time of S. litura. These findings suggest that the incidence of S. litura on groundnut could be higher in future.

Biodiversity of insect pests of rice in India

Insect pests of rice are affected by climate change directly through physiological effects due to changes in temperature and precipitation and indirectly through effects due to changes in the quality of host plants. Species that depend on each other like plants and insects that pollinate them, do not always adapt to changes at the same time. The environmental changes alter both the timings and rate of interactions with food plants, competitors and natural enemies. Loss of genetic variability in the newly established host range tends to influence the ability of insect populations to adapt the changing climatic conditions involving new food plants, competitors and natural enemies. It is interesting to mention that the insect pest scenario of the crop gradually changing with gradual changes in crop cultivation practices and climate change, especially the higher temperature. Several major pests have become minor and many minor pests attained the status of major pests. There are records of many new pests shifting the host and also some invasive pests due to change in their habitat. There are many good examples of such changing insect pest scenario in rice crops.

Invasive Insect Pest Scenario in India: A threat to biodiversity

Invasive insect species are non-native or exotic that occur outside their natural adapted habitat and dispersal potential. Although invasive alien species have been identified as the second greatest threat to biodiversity after habitat loss, characterizing and quantifying their impacts on native species and habitats remains a fundamental problem in the conservation biology. These species are causing enormous damage to biodiversity and the valuable natural agricultural systems upon which we depend. Direct and indirect health effects are increasingly serious and the damage to nature and environment is often irreversible. The impact of invasion of insect pests can be minimized with international cooperation through exchange of information on invasive pests and their natural enemies. The interdisciplinary coordinated work among researchers help in identifying and assessing their ecological problems.

Web-Based system for study of pest dynamics in relation to climate change

A web based system for study of Real Time Pest Dynamics (RTPD) was developed and implemented under National Initiative in Climate Resilient Agriculture to assess the field level impact of climate change on pest dynamics of four major crops viz., rice, pigeon pea, groundnut and tomato. Understanding pest dynamics vis-a-vis climate change is essential for prediction of pest severity. Predictions lead to pest forewarning that provides lead time for managing impending pest attacks, minimizes crop loss, and optimizes pest control leading to reduced cost of cultivation and better environmental safeguards. The current efforts mainly focus on pest data capture, reporting, analysis and its relation with weather data. The system consists of three major components viz. a database, an offline peat data capture application and online pest-weather reporting and analysis application. Pest and other relevant information obtained through regular monitoring of experimental and farmer's fields by Real Time Pest Surveillance (RTPS) locations established across the major agro ecological regions growing the target crops and daily weather data for these locations is captured on weekly basis by an offline application deployed at computers of RTPS locations which is transferred to central database. Subsequently, experts from research institutes view this information in various formats through online reporting and analysis application to compare pest scenarios, to study pest weather interactions as well as for generation of pest forewarning models.

Pest scenario and appropriate management for Bt cotton in Belgaum Karnataka

Prior to introduction of Bt cotton the Belgaum district had more area under short staple and very less area under extra long staple cotton. After the introduction of Bt cotton in 2003-2004 in Belgaum district, the area under cotton decreased however, yield levels increased drastically. Bt cotton suppressed bollworms which were major threat but at the same time minor sucking pests such as mealy bug and mirid bug emerged as major pests, with the regularly occurring jassids, thrips, white flies and natural enemies, disease and disorders. The increased length of cropping period for extra long Bt hybrids was the reason for more occurrence for pest and diseases. The unscientific follow up of general recommendations with more number of sprays, lowered the interest of farmers in taking up Bt cotton. However, the study area followed scientific and appropriate management practices with minimum dosage and less number of sprays for control of pests. This resulted in acceptance of Bt cotton in and around project area. The project was carried out in Belgaum district of Karnataka state covering 42 villages for consecutive years till 2014. The study carried out over the years at selected locations has demonstrated avoidable losses due to important pests and diseases on cotton.

Impact of eCO2 and Temperature on Aphis craccivora koch. on Groundnut and Future Pest Status During Climate Change Scenarios

Impact of eCO2 and Temperature on Aphis craccivora koch. on Groundnut and Future Pest Status During Climate Change Scenarios Studies were conducted to quantify the direct effects of temperature and indirect effect of elevated CO2 (eCO2), on Aphis craccivora Koch. on groundnut (Arachis hypogaea L.). The mean development time (DT) of nymph was significantly reduced by 1-2 days from 20 to 35°C temperature at eCO2 over ambient CO2 (aCO2) conditions. Increased production of offspring was noticed at eCO2. The thermal requirement of nymph varied from 74-102 DD on eCO2 with temperature in the range of 20-30°C as against 90-130 DD on aCO2. Non-linear mostly quadriatic relationship of lifetable parameters rm, Ro, T and λ varied with temperature and CO2 and found to have nonlinear relationship. Prediction of pest scenarios based on PRECIS A1B emission scenario data at eleven groundnut cultivating locations of India during near (NF) and distant future (DF) periods showed that increase of ‘rm’ and ‘λ’ with varied ‘Ro’ and reduced ‘T’. Similar trends were reflected in three decadal periods of NF also. The present results indicate that incidence of A. craccivora is likely to be higher in the future climate change periods.

Pest scenario in rice in eastern Uttar Pradesh

Pest scenario in rice in eastern Uttar Pradesh

Prediction of Pest Scenarios of Spodoptera litura Fab. in Peanut Growing Areas of India During Future Climate Change

The present study predicted a pest scenario of pheromone trap catch of adults of tobacco caterpillar, Spodoptera litura. The relationship between temperature and adult pheromone trap catch was quantified using historical insect pest data obtained from respective locations and these models were adopted to predict the future pest scenarios during three decadal periods of ‘near future’ (NF-2021-2050) viz., I (2021–2030), II (2031–2040) and III (2041–2050). It is predicted that the moth catch would be higher (233) during all three future decades (172–233) than present period (93.46) at Dharwad location and similar trend was observed at other three locations with significant year wise variations. The present work indicates that the temperature could play a significant role in population dynamics of S. litura and it is likely that the pest incidence would be higher during future climate change scenario.

Model and scenario variations in predicted number of generations of Spodoptera litura Fab. on peanut during future climate change scenario.

The present study features the estimation of number of generations of tobacco caterpillar, Spodoptera litura. Fab. on peanut crop at six locations in India using MarkSim, which provides General Circulation Model (GCM) of future data on daily maximum (T.max), minimum (T.min) air temperatures from six models viz., BCCR-BCM2.0, CNRM-CM3, CSIRO-Mk3.5, ECHams5, INCM-CM3.0 and MIROC3.2 along with an ensemble of the six from three emission scenarios (A2, A1B and B1). This data was used to predict the future pest scenarios following the growing degree days approach in four different climate periods viz., Baseline-1975, Near future (NF) -2020, Distant future (DF)-2050 and Very Distant future (VDF)—2080. It is predicted that more generations would occur during the three future climate periods with significant variation among scenarios and models. Among the seven models, 1–2 additional generations were predicted during DF and VDF due to higher future temperatures in CNRM-CM3, ECHams5 & CSIRO-Mk3.5 models. The temperature projections of these models indicated that the generation time would decrease by 18–22% over baseline. Analysis of variance (ANOVA) was used to partition the variation in the predicted number of generations and generation time of S. litura on peanut during crop season. Geographical location explained 34% of the total variation in number of generations, followed by time period (26%), model (1.74%) and scenario (0.74%). The remaining 14% of the variation was explained by interactions. Increased number of generations and reduction of generation time across the six peanut growing locations of India suggest that the incidence of S. litura may increase due to projected increase in temperatures in future climate change periods.

Impact of areawide integrated pest management strategies on pests of pigeonpea and yield in Marathwada region of Maharashtra, India

Pigeonpea [Cajanus cajan (L.) Millsp.] is an important legume crop of southern Maharashtra, providing high quality protein and animal feed. Insect pests feeding on flowers and pods of this crop are the most important biotic constraint affecting yield to the tune of 60 per cent. Hitherto, focus of pest management research has been on podborer, Helicoverpa armigera (Hubner). With large scale cultivation of transgenic cotton in Maharashtra and climatic changes, pest scenario has changed requiring more attention on leaf webber, Maruca and pod fly. Hence, area wide implementation of Integrated Pest Management (IPM) in pigeopea was implemented during 2010-11 and 2011-12 covering 5 taluks benefitting 2449 farmers of 8 villages. It was observed that use of pesticides based on the “e-Pest monitoring and its subsequent decision support tools” enabled to manage pests with judicious use of pesticides. The pest infestation (pod borer, pod fly, plume moth, flower webber, etc.,) were significantly low as compared to non-IPM with appreciable high population of natural enemies (coccinellids, chrysopa and spiders) were also observed under IPM fields. Timely dissemination of advisories and action has resulted in higher grain yield of 9.89 q/ha and lower grain damage 5.69 per cent as compared to non-IPM (13.79 per cent).