Pest Population Dynamics Research Articles

Honeydew: A keystone in insect–plant interactions, current insights and future perspectives

AbstractHoneydew, a sugary excretion produced by sap‐feeding insects, plays a pivotal role in shaping intricate interactions between insects and plants. This review explains the multifaceted aspects of honeydew, beginning with an overview of its production mechanisms and factors influencing its variability across insect species and plant hosts. Exploring its composition, we examine the chemical components and nutritional aspects, highlighting variations based on insect species and plant sources. The impact of honeydew on microbial communities is explored, shedding light on its role in influencing the diversity and abundance of microorganisms. Furthermore, the review investigates how honeydew affects pest behaviour and population dynamics, elucidating plant responses to honeydew deposition. In the realm of biocontrol, we examine the intricate relationships between honeydew and natural enemies, considering potential implications for integrated pest management. Beyond these individual components, the paper discusses the broader ecological consequences of honeydew in ecosystems, emphasizing the interconnected relationships between insects, plants and microorganisms. The review concludes by identifying research gaps and suggesting future directions, recognizing the need for further investigation into areas with potential applications for agriculture and ecology. This review provides a comprehensive synthesis of the current understanding of honeydew's significance in insect–plant interactions, offering insights for both researchers and practitioners in the field.

E-Pest Surveillance for Assessment of Seasonal Occurrence of Orange Pests in Maharashtra

Monitoring of incidence and intensity of pests over the crop season is crucial for effective pest management. ICT (Information and communication technology) not only enables the assimilation of pest databases over space and time, but also aids in the rapid processing of data to make pest management decisions using the available knowledge base and essential inputs that can be mobilised and adopted for plant protection on wide area basis. This study generated valuable data on the population dynamics of orange pests over the seasonal months from 2012 to 2022 with the aid of applied information and communication technology tools. The majority of the pests under current study showed their seasonal activity throughout the monitoring period. The study on the seasonal incidence revealed bark eating caterpillar Inderbela sp. having their peak infestation during September and October whereas January to March were observed as prime months for fruit sucking moths Othreis sps to reach their peak prevalence and damage. The citrus leaf miner Phyllocnistis citrella population dynamics showed two peaks in August and September. The data generated in this study would help in the forecast of the pests and helpful in devising an effective IPM strategy.

To study the population dynamics of major insect pests in black gram (Vigna mungo L. Hepper) in relation to weather parameter

to study the population dynamics of major insect pests in black gram (Vigna mungo L. Hepper) in relation to weather parameter

Population Dynamics of Helicoverpa armigera in Chickpea, (Cicer arietinum L.)

The present studies on population dynamics of gram pod borer insect pest were carried out at Students’ Instructional Farm (SIF) of Acharya Narendra Deva University of Agriculture & Technology, Kumarganj, Ayodhya (UP), India during Rabi 2022-23 and 2023-24. The present study revealed that gram pod borer, Helicoverpa armigera was commenced from the first fortnight of November and touched the highest at 8th SMW (2.98 pod borer larvae per plant) and 7th SMW (3.54 pod borer larvae per plant) in both the year, respectively. The population of H. armigera had a non-significant positive correlation with rainfall (r= 0.101) in Rabi 2022-23. The population of H. armigera had a significant positive correlation with wind speed (r= 0.495*) in Rabi 2023-24.

From problem to progress: Rodent management in agricultural settings of sub-Saharan Africa and calling for an urban perspective

In sub-Saharan Africa, agricultural intensification and urbanization have increased the risk of proliferation of rodents in rural and urban habitats. Management of rodent populations is a challenge in terms of food security and public health. However, conventional efforts to manage rodents are currently reactive and based on the inadequate use of synthetic chemical rodenticides, including first- and second-generation anticoagulants and acute rodenticides. This approach carries substantial environmental and health risks and has yielded limited success in terms of reduction of rodent populations sustainably. In this paper, which is the second part of a diptych, we advocate for a shift towards more sustainable and environmentally friendly approaches, such as Ecologically-Based Rodent Management (EBRM), as a realistic alternative to synthetic rodenticides. This method is based on a good knowledge of habitat use, species diversity and population dynamics of major rodent pests, and involves community-based interventions aimed at reducing rodent abundance to economically and hygienically acceptable levels in the long term. We present for the first time a comprehensive compilation of published and unpublished information derived from observational field studies conducted in Ethiopia, Niger, Nigeria, Benin, Mali, Mauritania and Senegal with the aim to provide an overview of EBRM case studies in these countries of sub-Saharan Africa. This paper intends to serve as a catalyst for change, encouraging the transformation of rodent management practices towards sustainable methods. We aim at stimulating further research and interventions that promote EBRM in Africa, ultimately fostering more environmentally conscious and effective solutions.

Population dynamics of corn insect pests in Ukraine under climate change

Aim. To determine the specificities of perennial dynamics in the number of the main corn insect pests in different natural and climatic zones of Ukraine under climate change. Methods. The field, laboratory, mathematical methods were used. The materials of the phytosanitary entomological monitoring of the State Service of Ukraine on Food Safety and Con- sumer Protection (2005–2021) in the basic 161 enterprises in Ukraine’s regions using methodologically standardized annual registrations of the main harmful organisms of agrocenoses (Borzykh еt al, 2018). Six groups of the main corn insect pests were investigated: corn borers (Ostrinia nubilalis Hübner), wireworms (Elateridae) and false wireworms (Te- nebrionidae), cutworms (Noctuida), southern dusty surface beetle (Tanymecus dilaticollis Gyllenhal), cotton bollworm (Helicoverpa armigera Hübner), and cereal aphids (Schizaphis graminum) Rondani. The database of the Hydrometeoro- logical Center of Ukraine was used to analyze climate parameters (2005–2021). The statistical analysis of the data was conducted using MS Excel and the linear correlation-regression analysis according to Pearson, Student’s criterion was used to evaluate the reliability (probability) of the correlation coefficients. Results. The results of correlational analysis of the state of populations of the main corn insect pests demonstrated that climate change has not considerably affected the number of corn borers as well as wireworms and false wireworms in all the natural and climatic zones of Ukraine yet. A reliable moderate reverse correlation (r = –0.309) was found between the number of cutworms and the sum of effective temperatures (SET) only for the Forest-Steppe conditions – under the increase in the SET, the number of these insects was smaller. The number of the southern dusty surface beetle was in direct, reliable, moderate correlation (r = 0.335) with the SET in the Steppe, for instance, the pest responded to the increase in the SET with the rise in its number. The number of cotton bollworms in Polissia was in reliable moderate correlation (r = –0.489) with the SET. The number of cereal aphids was in a reliable moderate direct correlation (r = 0.529) with the SET in Polissia: at the increase in the SET, the number of these pests was increasing. Conclusions. Conclusions: Climate changes do not considerably affect the state of the populations of the main corn insect pests in all the natural and climatic zones of Ukraine yet: we found the correlations between the number of insect pests and the SET which did not exceed such values as weak, moderate, and conspicuous. Significant changes in the state of insect pest populations should be expected if the sum of effective temperatures during the vegetation period will considerably affect the performance and feeding qualities of the cultivated plants.

Expansion of apple cultivation increases the abundance of codling moth (Cydia pomonella) in agricultural landscapes of China.

Agricultural land-use change is an important driver of pest population dynamics, and can alter source-sink dynamics and the concentration-dilution effects of the landscape. Understanding the effects of land use on pests at both landscape and regional levels is essential for the development of sustainable pest management strategies given the large changes occurring in cropping systems in China. At the landscape level, we investigated the impacts of landscape composition and edge density on pheromone trap catch of codling moth (Cydia pomonella) in apple orchards, in Aksu, Xinjiang, China. At the regional scale, we conducted a meta-analysis using data from studies performed across the Aksu area in recent decades, to assess the relationship between trends in codling moth abundance and the area of apple cultivation. Both extensive planting of apple and large areas of annual crops in the landscape increased the abundance of codling moth, whereas the presence of secondary host plants (peach, pear, walnut, plum, and apricot) had a negative effect. Seminatural habitats and landscape edge density did not significantly affect codling moth abundance. The responses of different generations of codling moth to landscape factors were varied. At the regional level, codling moth occurrence was positively correlated with the expansion of apple production areas. Expansion of apple cultivation increases the abundance of codling moth in agricultural landscapes. We recommend decreasing the area devoted to monocultures of apple when designing agricultural landscapes and increasing plantings of secondary host crops to dilute and reduce the abundance of codling moth. © 2024 Society of Chemical Industry.

The Diversity of Parasitoids and Their Role in the Control of the Siberian Moth, Dendrolimus sibiricus (Lepidoptera: Lasiocampidae), a Major Coniferous Pest in Northern Asia.

The Siberian moth, Dendrolimus sibiricus Tschetv., 1908 (Lepidoptera: Lasiocampidae) is a conifer pest that causes unprecedented forest mortality in Northern Asia, leading to enormous ecological and economic losses. This is the first study summarizing data on the parasitoid diversity and parasitism of this pest over the last 118 years (1905-2022). Based on 860 specimens of freshly reared and archival parasitoids, 16 species from two orders (Hymenoptera and Diptera) were identified morphologically and/or with the use of DNA barcoding. For all of them, data on distribution and hosts and images of parasitoid adults are provided. Among them, the braconid species, Meteorus versicolor (Wesmael, 1835), was documented as a parasitoid of D. sibiricus for the first time. The eastern Palaearctic form, Aleiodes esenbeckii (Hartig, 1838) dendrolimi (Matsumura, 1926), status nov., was resurrected from synonymy as a valid subspecies, and a key for its differentiation from the western Palaearctic subspecies Aleiodes esenbeckii ssp. esenbecki is provided. DNA barcodes of 11 parasitoid species from Siberia, i.e., nine hymenopterans and two dipterans, represented novel records and can be used for accurate molecular genetic identification of species. An exhaustive checklist of parasitoids accounting for 93 species associated with D. sibirisus in northern Asia was compiled. Finally, the literature and original data on parasitism in D. sibiricus populations for the last 83 years (1940-2022) were analysed taking into account the pest population dynamics (i.e., growth, outbreak, decline, and depression phases). A gradual time-lagged increase in egg and pupal parasitism in D. sibiricus populations was detected, with a peak in the pest decline phase. According to long-term observations, the following species are able to cause significant mortality of D. sibiricus in Northern Asia: the hymenopteran egg parasitoids Telenomus tetratomus and Ooencyrtus pinicolus; the larval parasitoids Aleiodes esenbeckii sp. dendrolimi, Cotesia spp., and Glyptapanteles liparidis; and the dipteran pupal parasitoids Masicera sphingivora, Tachina sp., and Blepharipa sp. Their potential should be further explored in order to develop biocontrol programs for this important forest pest.

Low concentrations of cyantraniliprole negatively affects the development of Spodoptera frugiperda by disruption of ecdysteroid biosynthesis and carbohydrate and lipid metabolism

In addition to the acute lethal toxicity, insecticides might affect population dynamics of insect pests by inducing life history trait changes under low concentrations, however, the underlying mechanisms remain not well understood. Here we examined systemic impacts on development and reproduction caused by low concentration exposures to cyantraniliprole in the fall armyworm (FAW), Spodoptera frugiperda, and the putative underlying mechanisms were investigated. The results showed that exposure of third-instar larvae to LC10 and LC30 of cyantraniliprole significantly extended larvae duration by 1.46 and 5.41 days, respectively. Treatment with LC30 of cyantraniliprole significantly decreased the pupae weight and pupation rate as well as the longevity, fecundity and egg hatchability of female adults. Consistently, we found that exposure of FAW to LC30 cyantraniliprole downregulated the mRNA expression of four ecdysteroid biosynthesis genes including SfNobo, SfShd, SfSpo and SfDib and one ecdysone response gene SfE75 in the larvae as well as the gene encoding vitellogenin (SfVg) in the female adults. We also found that treatment with LC30 of cyantraniliprole significantly decreased the whole body levels of glucose, trehalose, glycogen and triglyceride in the larvae. Our results indicate that low concentration of cyantraniliprole inhibited FAW development by disruption of ecdysteroid biosynthesis as well as carbohydrate and lipid metabolism, which have applied implications for the control of FAW.

Population Dynamics of Major Lepidopteran Pests on Cauliflower

A field experiment on the population dynamics of major lepidopteran pests on cauliflower revealed the maximum incidence of diamond back moth (Plutella xylostella L), leaf webber (Crocidolomia pavonana F), leaf eating caterpillar (Spodoptera litura F) and semilooper (Trichoplusia ni Hubner) on 7th, 4th, 6th and 5th standard meteorological week (5.30, 3.90, 7.20 and 2.90 larvae/ plant, respectively). The correlation of incidence of larvae of diamond back moth and leaf eating caterpillar showed a highly significant positive correlation with bright sunshine hours (r = 0.699 and 0.772, respectively). Evening relative humidity showed a highly significant negative correlation (r = -0.687 and -0.749, respectively). Maximum and minimum temperature and morning vapour pressure exhibited a highly significant negative correlation with the leaf webber (r = -0.696, -0.866 and -0.826, respectively). The incidence of semilooper showed a significant negative correlation with minimum temperature and morning vapour pressure (r = -0.698 and -0.605, respectively).

Population Dynamics of Major Sucking Pests Infesting Rabi Groundnut in West Bengal

A field investigation was carried out at the Central research Farm, Gayeshpur, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal during rabi 2021-2022 to study the seasonal incidence of the major sucking pests infesting the summer groundnut. The silverleaf whitefly (Bemisia tabaci Genn.), jassids (Empoasca kerri Pruthi), black aphids (Aphis craccivora Koch) and flower thrips (Megalurothrips usitatus Bagnall) were considered as the major sucking pests; B. tabaci was first observed on the 49th standard meteorological week, whereas M. usitatus, E. kerri and A. craccivora were first seen during the 5th, 6th and 7th standard meteorological week. The whitefly population showed a significant negative correlation (-0.586) with average temperature, while the thrips showed a significant negative correlation (-0.578) with average relative humidity.

Application of a Mechanistic Model to Explore Management Strategies for Biological Control of an Agricultural Pest

Despite the known benefits of integrated pest management, adoption in Australian broadacre crops has been slow, in part due to the lack of understanding about how pests and natural enemies interact. We use a previously developed process-based model to predict seasonal patterns in the population dynamics of a canola pest, the green peach aphid (Myzus persicae), and an associated common primary parasitic wasp (Diaeretiella rapae), found in this cropping landscape. The model predicted aphid population outbreaks in autumn and spring. Diaeretiella rapae was able to suppress these outbreaks, but only in scenarios with a sufficiently high number of female wasps in the field (a simulated aphid:wasp density ratio of at least 5:1 was required). Model simulations of aphid-specific foliar pesticide applications facilitated biological control. However, a broad-spectrum pesticide negated the control provided by D. rapae, in one case leading to a predicted 15% increase in aphid densities compared to simulations in which no pesticide was applied. Biological and chemical control could therefore be used in combination for the successful management of the aphid while conserving the wasp. This modelling framework provides a versatile tool for further exploring how chemical applications can impact pests and candidate species for biological control.

Influence of Weather Factors on the Incidence of Major Insect Pests of Sesame (Sesamum indicum L.)

Population dynamics of major pests viz., web worm, Antigastra catalaunalis (Duponchel), leaf hoppers Orosius albicinctus (Distant) and gallfly Asphondilia sesami (Felt) infesting sesame was studied in Coimbatore, Tamil Nadu, India during Rabi and Kharif seasons of the year 2020. Correlation between the pest population, percent damage and weather parameters was analyzed and regression equations were developed. The incidence of leaf hoppers, web worm and gallfly on sesame crop during Rabi season started on 4th, 3rd and 7th Standard meteorological week (SMW) respectively. The peak attained on 8th,11th, and 11th SMW with population of leafhoppers and damage by web worm and gallfly (2.01/plant,60.04 percent and 49.68 percent) respectively during Rabi season. In case of leafhopper and web worm, minimum temperature (r=0.031r=0.373) had non-significant positive correlation whereas mean relative humidity (r=-0.02) registered non-significant negative correlation with leaf hopper and web worm significant negative correlation Gall fly incidence showed significant positive correlation with maximum and minimum temperature. Whereas in Kharif season, incidence of leafhoppers, web worm and gallfly on sesame crop started on 33rd, 32nd and 37th SMW respectively. The peak activity and incidence was noticed during 37th, 39th and 40th SMW for leafhoppers, web worm and gallfly respectively. The correlation between weather parameters and incidence of major pests followed a similar pattern to kharif season. Regression analysis data revealed that the multiple non-linear regression equations are sufficient to predict the pest population with prevailing weather parameters.

Studies on population dynamics of major pests of okra

Okra [Abelmoschus esculentus (L.) Moench] is known tobe infested by many insect pest among them the most important onesare sucking pests like aphids, leafhopper, whitefly and fruit borerslike Earias vitella and Helicoverpa armigera. Controlling these pestsis very much important to obtain good yield, hence knowledge aboutthese pest incidence needed for taking up management practices. Inthis context, okra was sown during last week of November (rabi2020-21) and observations were recorded at weekly interval. Peakincidence of aphid (23.44 aphids/3 leaves) and leafhopper (16.97leafhopper/3 leaves) noticed during last week of December, whitefly(12.70 whiteflies/3 leaves) during second week of March. Fruit borersduring third week of February and second week of March with percent fruit damage of 44.9 (Earias vitella) and 13.59 (Helicoverpaarmigera).Sucking pests incidence more up to 10th week old crop,there after the population declined. In case of fruit borers, theypersisted upto end of the season

Population dynamics of insect pest associated with barnyard millet in Bihar

Population dynamics of insect pest associated with barnyard millet in Bihar

Influence of weather factors on population dynamics of major sucking pests of Bt cotton

Influence of weather factors on population dynamics of major sucking pests of Bt cotton

INSECT BIODIVERSITY AND ASSESSMENT OF POST-HARVEST GRAIN LOSSES IN STORED COWPEA (Vigna aunguiculata L.)

Insect pests cause huge economic losses to stored grain cereals and pulses in tropical and subtropical areas around the globe. The level of damage and losses caused by different insect pests varies depending upon the infesting species, type of food materials, duration of storage and structures. The information about the diversity of infesting species, their dispersal and abundance are key for devising effective pest management techniques against storage insect pests. The present study aimed to collect information on the distribution, relative abundance and biodiversity of major insect pests of stored cowpeas in Dera Ismail Khan (Khyber Pakhtunkhwa) and its adjoining Punjab province areas of Pakistan. The areas selected for biodiversity studies were Paniala, Mankera, Bhakkar, Paharpur, Kulachi, Ramak, Dera Ismail Khan, Darya Khan, Notak and Behal. A vast survey of godowns was conducted to find out the population dynamics of insect pests of stored cowpeas and to explore the % grains damage and weight losses in the mentioned areas. For the collection of samples, a spear sampler was used to collect 500-gram samples from the top, middle and bottom portions of the bags. Samples were preserved in plastic containers and after 30 days, were sieved out with the help of a 2mm mesh sieve to remove different types of dead and alive insects. A total of five species representing two distinct orders i.e., Coleoptera and Lepidoptera. Coleopterans are Callosobruchus maculatus, Tribolium castaneum, Oryzaephilus surinamensis, Trogoderma granarium belonged to four families including Chrysomelidae, Tenebrionidae, Silvanidae, Dermestidae and Lepidopteron are Sitotroga cerealella belonging to family Gelechidae. The most abundant species among all the recorded insect pests of cowpea was C. maculatus (53.60%) followed by T. castaneum (18.60%), S. cerealella (16.97%), O. surinamensis (6.49%) and T. granarium (04.34%). The maximum infestation (26.98%) and weight loss (28.91%) of cowpea was recorded in Darya Khan followed by Dera Ismail Khan (22.70% and 26.33%), whereas; minimum % infestation and weight losses were recorded in Bhakkar (16.91% and 17.14%) area showing significant differences between the surveyed areas. The C. maculatus is the most abundant specie of the stored cowpea grains in the surveyed areas and needs management tactics to minimize the post-harvest grains losses. The population of C. maculatus starts to build up during the month of March (23.30⁰C and 56.25% RH) and reaches at peak in May (35.32⁰C and 68.88% RH). Special measures should be taken during these months to minimize the infestation and losses caused by C. maculatus.

LONG-TERM (2005-2020) WINTER WHEAT PEST POPULATION DYNAMICS IN UKRAINE IN RESPONSE TO EFFECTS OF ACREAGE TREATED WITH INSECTICIDES AND CLIMATE CHANGE

We studied the long-term population dynamic`s (2005-2020) of six main insect pests of winter wheat (late wheat shoot fly, hessian fly, frit flies, cereal beetles, corn ground beetle and sun pest) in three climatic zones of Ukraine under conditions of increasing areas of application pesticides and global warming. The aim of the research was to investigate how these factors influence pest population dynamics. Comparison of sums of effective temperatures (SET) with standard values for different zones indicates significant climate warming over the past 15 years. Correlation analysis with two variables showed a general decrease in the numbers of most populations, especially in the steppe and forest-steppe zones.

Population dynamics of insect pests and their natural enemies in pearl millet ecosystem

Field experiment was carried out at the Regional Agricultural Research Station, Vijayapura, to study population dynamics of insect pests and their natural enemies in pearl millet ecosystem. The present study revealed that, dead heart per cent (14.45%) due to shoot fly, Atherigona approximata (Malloch) was peak during 35th Standard Meteorological Week (SMW), per cent damage due to stem borer, Chilo partellus (Swinhoe) was at peak during the 37th SMW (4.55%) and highest blister beetle, Lytta sp. population was observed during 38th SMW (12 beetles/ 5 Ear heads). While, the maximum population of aphid Rhopalosiphum maidis (Fitch) and its predators, such as coccinellids Cheilomenes sexmaculata (Fabricius), Harmonia octomaculata (Fabricius) and spiders were recorded during the 34th SMW and the green lacewing Chrysoperla zastrowi sillemi (Ebson-petersen) population at 35th SMW. The correlation studies indicated that, dead heart per cent due to shoot fly revealed a significant positive correlation with maximum temperature (r= 0.588*) and stem borer infestation revealed a significant positive correlation with maximum relative humidity (r= 603*) and sunshine hours (r= 585*). None of the weather parameters showed a significant correlation with the incidence of blister beetle and aphid populations.

Silicon compounds promotes physiological response of avocado 'Hass’ and affect the development of pests

The use of silicon (Si) can minimize the adverse effects of abiotic stresses, increase resistance against arthropod pests, and promote growth in fruit crops. Considering the beneficial effects of Si reported in various crops and the limited information on its effect on avocado, this study investigated the effects of the application of two sources of Si (acidic and alkaline) on the physiology, growth, and population dynamics of arthropod pests of 'Hass’ avocado plants. Three experiments were carried out at three different plant development stages: seedlings (Fresno, Tolima), young (Bituima, Cundinamarca), and adult trees (El Tablazo, Tolima). The treatments were as follows:1) plants without Si application (control), 2) plants with foliar application of acidic Si, 3) plants with foliar application of basic Si, and 4) plants with foliar treatment of acidic and basic Si and pyrethrins. Foliar applications of Si caused less accumulation of adult arthropod pests such as Heliothrips haemorrhoidalis, Monalonion velezangeli, Polyphagotarsonemus latus, Bombacoccus aguacatae, Paraleyrodes sp., and Oligonychus yothersi compared to the control treatment. Foliar applications of Si (both sources) also increased plant height and shoot length. Si had a positive effect on leaf stomatal conductance, chlorophyll content, and plant hydraulic conductivity at the end of the three experiments. The results obtained allow us to conclude that the use of Si can be considered a complementary tool in the management of some arthropod pests in avocados. In addition, Si may help in the management of avocado crops by improving the physiological responses of plants at different developmental stages.