Pest Abundance Research Articles

Survey on the Occurrence of Insect Pests in Stored Grains in Thiruvananthapuram District, Kerala State

To identify the species composition and relative abundance of insect pest in stored grains, a preliminary investigation was conducted by collecting grain samples from 16 grain merchant stores in Thiruvananthapuram District, Kerala state. Insect pest collected during the study were pulse beetle, Callosobruchus chinensis, cow pea beetle, C. maculatus, grain weevil, Sitophilus granarius, long headed flour beetle, Latheticus oryzae, rice weevil, Sitophilus oryzae, red flour beetle, Tribolium castaneum, lesser grain borer, Rhyzopertha dominica, saw toothed grain beetle, Oryzaephilus surinamensis, Angoumois grain moth, Sitotroga cerealella. Tribolium castanaeum, Sitophilus oryzae, Rhizopertha dominica (32.25%, 24.51%, 21.91% respectively per 200 g sample) were the most abundant pest species in the grain samples.

The impact of field margins on biological pest control: a meta-analysis

Floral field margins are known to benefit invertebrate species diversity and abundance within agricultural landscapes, but variation in success limits widespread uptake. Understanding how variation within floral field margins can affect certain entomological groupings is lacking but would allow for a more individualised design of margins to enhance biological control. This meta-analysis aims to answer the question; do floral field margins benefit biological pest control over grassy field margins? We found that floral margins significantly benefit the natural enemy community and biological control services, relative to non-floral grass margins. We confirm that field margin type is linked to higher abundance and diversity of natural enemies, lower numbers of herbivorous invertebrate pests, and reduced crop damage. We consider whether specific characterisations of natural enemies and pest communities vary between these margin types, finding key differences in the abundances of aerial and epigeal enemies, the diversity of parasitoid and predatory enemies and pest abundances found in naturally regenerating and sown floral field margins. The finding here cements the implementation of floral field margins as a legitimate control method for crop pests in the face of losses due to pesticides and highlights design and management considerations for the success of floral margins.

Back to the 'roots' of research: a hypothesis-driven approach provides predictive understanding of plant-herbivore-microbe interactions.

This article is a Commentary on Böttner et al. (2023), 239: 1475–1489.

Abundance of Major Insect Pests in Rice and Their Relation to Weather Parameters

The present investigation has been conducted in rice crop during Kharif 2021-22at Students’ Instructional Farm of Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya (U.P.), India. The population of six major insect pests was recorded viz. Rice Yellow stem borer (Scirpophaga incertulus), Rice Leaf folder (Cnapholocrocis medinalis), Rice ear head bug (Leptocorisa acuta), Brown plant hopper (Nilaparvata lugens), White backed plant hopper (Sogatella furcifera)and Green leaf hopper (Nephotettix nigropictus) that cause most damage at different crop growth stages initiated after sowing till harvesting. The maximum population of yellow stemborer was observed on rice crop at 36th SMW (12.20 per cent dead heart). The infestation of dead heart was non-significant positively correlated with minimum, maximum temperature and RH% (0.433, 0.010 & 0.253 respectively) and negatively correlated with rain fall (0.081) whereas, significant negatively correlated with sunshine (0.552*). The maximum population white ear in 40th SMW (16.80 per cent). The infestation of white ear was non-significant negative correlation with minimum, maximum temperature (-0.062, -0.167) and positive correlation with RH & rain fall (0.244 & 0.173) whereas, significant positive correlation with sunshine (0.703*). Maximum leaf folder population was observed during 35th SMW (16.35 per cent). and infestation of leaf folder was non-significant positive correlation with minimum temperature & RH (0.427 & 0.505) and negative correlation with maximum temperature, rainfall and sunshine (-0.079, -0.030 & -0.291). The maximum population was recorded of ear head bug in 38th SMW i.e., (10.90 ear head bug/hill respectively.). The infestation of ear head bug was non-significant positive correlation with minimum temperature, RH, rainfall & sunshine (0.061, 0.176, 0.155 & 0.210) and negative correlation with maximum temperature (-0.407). The peak mean population of BPH was recorded in 37th SMW i.e., (11.25 brown plant hopper/hill respectively.) Itwas non-significant positive correlation with minimum temperature & RH (0.463 & 0.357) and negative correlation with maximum temperature & rainfall (-0.066 & -0.088) whereas, significant negative correlation with sunshine (-0.597*), The peak mean population of WBPH was recorded in 38th SMW i.e., (12.80 white backed plant hopper/hill respectively.) It was non-significant positive correlation with minimum temperature, RH & rainfall (0.300, 0.337 & 0.185) and negative correlation with maximum temperature (-0.300) whereas, significant negative correlation with sunshine (-0.094*) and the maximum population of green leaf hopper was recorded in 37th SMW i.e., (10.80 green leaf hopper/hill respectively.) with the infestation of green leaf hopperwas non-significant positive correlation with minimum temperature & RH (0.479 & 0.369) and negative correlation with maximum temperature & rainfall (-0.077 & -0.120) whereas, significant negative correlation with sunshine (-0.633*).

Impact of four biofertilizers on the abundance of insect pests of eggplant, Solanum melongena (L) under soilless conditions: Evaluation of the net yield of fruits and nutrient contents of the plant.

Impact of four biofertilizers on the abundance of insect pests of eggplant, Solanum melongena (L) under soilless conditions: Evaluation of the net yield of fruits and nutrient contents of the plant.

Abundance of pests of flood recession maize (Zea mays L.) in the Senegal River Valley

Abundance of pests of flood recession maize (Zea mays L.) in the Senegal River Valley

Abundance of pests of flood recession maize (Zea mays L.) in the Senegal River Valley

Maize, a foodstuff of economic and nutritional importance, is grown in Senegal in four regions such as the Senegal River valley, especially in the cold season. However, maize is subject to many pests. In view of the damage they cause, a knowledge of the entomofauna remains interesting. The abundance of the entomofauna of floodplain maize in the river valley, particularly in Dembancané, was determined. Thus, a population of 590 individuals was collected. Consequently, the absolute and relative abundance and frequency of occurrence or Constance were evaluated. The Kruskall-wallis test was performed followed by the DUNN test. Following this a Fisher test and a Chi-2 test were performed. From the beginning of flowering to the beginning of ripening, the study covered 58 species of insects and 5 species of spiders belonging to eight orders. The absolute abundance of species varies according to the plot and the development phase. In addition, Heteroptera are the most represented with 35.46% followed by Coleoptera and Orthoptera with 26.24%. The contribution of each species in this study area differs as a result of the different values found of relative abundance and Constance.

Influence of Plant Growth Retardants and Nitrogen Doses on the Content of Plant Secondary Metabolites in Wheat, the Presence of Pests, and Soil Quality Parameters

Wheat is the cereal most susceptible to lodging, particularly during the flowering period and at the early ripening stage. The use of plant growth retardants (PGRs) is especially recommended when intensive nitrogen (N) fertilisation is applied, which increases the susceptibility of plants to lodging. This paper presents the results of tests into the effects of PGRs (PGR0—control; PGR1—chlormequat chloride (CCC) + trinexapac-ethyl (TE); PGR2—chlormequat chloride (CCC) + ethephon (ET)), and N dose—N0, N20, N40, and N60 [0, 20, 40, and 60 kg N ha−1] on the content of selected plant secondary metabolites (PSM) in the Indian dwarf wheat (Triticum sphaerococcum Percival) of the Trispa cultivar, and on the abundance of insect pests. In the developmental stage of wheat (BBCH 39), insects were collected with an entomological net. The study also investigated the effect of experimental factors on the physicobiochemical properties of the soil (pH in KC, granulometric composition, total organic carbon TOC, total nitrogen TN, fractional composition of humus, and the activity of enzymes). An increase in the plant secondary metabolite (PSM) and FRAP (ferring reducing ability of plasma) contents following the application of PGRs and N fertilisation already from as low a rate as 20 kg ha−1 was demonstrated. A significant positive correlation was noted between the abundance of Oulema spp. and the contents of total polyphenols, chlorogenic acid, and FRAP. No such relationship was noted for Aphididae or Thysanoptera. TOC content was higher on the plots on which N fertilisation was applied at the highest rate and after the application of PGRs. The factor determining the TN content was N fertilisation. Soil samples of the PGR0 N0 treatment were characterised by the greatest proportion of carbon in the humic and fulvic acid fractions and by the smallest proportion of carbon in the humin fraction. N fertilisation increased the proportion of carbon in the humin fraction on the plots on which no PGRs were applied. The study demonstrated an increase in the activity of oxidoreductive enzymes following the application of higher N rates. The application of PGRs resulted in no inhibition of enzymes in the soil compared to the control (PGRs0).

Within-field crop diversity and landscape complexity decrease the abundance of fall armyworm larvae in maize cropping systems

The composition and spatial arrangement of multiple crop and non-crop habitats at a field and landscape levels have the potential to modify the abundance and structure of arthropod communities. In particular, semi-natural habitats can provide important life support functions to a range of natural enemies of agricultural pests. How such traits might affect generalist predators has poorly been considered in complex landscapes dominated by intercropping and trees within a mosaic of small-scale agricultural plots in Africa. The objective of the present study was to test the hypothesis that crop diversity and landscape complexity in maize cropping systems decrease the abundance of crop pests through natural regulation by generalist predators. For this purpose, we monitored the fall armyworm abundance and predation of sentinel larvae by predatory ants across a set of maize fields with contrasted within-field crop diversity and abundance of semi-natural vegetation including trees and shrubs in their surrounding landscape. A negative effect of crop diversity and landscape complexity on FAW abundance, and a species-specific effect on ant abundance, were observed. However, no significant effect of ant abundance or predation on FAW abundance was observed, suggesting that habitat complexity by itself or other natural enemy communities such as parasitoids could play a complementary role to explain FAW abundance in maize crops.

How landscape characteristics in a heterogeneous oil palm plantation mitigate pest abundance: A case study from Mapiripán, Colombia

The oil palm sector is widely known for its strong impact on biodiversity and human well-being. The United Nations Sustainable Development Goals (SDG) framework calls for a sustainable biodiversity management approach to oil palm plantations and thereby balancing palm oil production and biodiversity conservation. Heterogeneous agricultural landscapes, comprising different vegetation types in a complex spatial pattern, provide habitat to a variety of species and support high biodiversity. Biodiversity can thus offer pest control ecosystem services to agricultural systems. However, so far it remains unclear whether landscape structure and diversity foster or mitigate pest occurrences in plantations. Our case study is the oil palm plantation of Mapiripán in Colombia, which integrates local ecosystems such as secondary forests, relict old-grown forests, riparian forests, and water body remnants in between and around the palm stands of the plantation. With this nature-improved design, we ££pose two main questions: which landscape structural properties characterize the landscape of the oil palm plantation?, and how do specific landscape structural properties foster or mitigate the presence of two main oil palm pests (the butterfly larvae split-banded owlet (Opsiphanes cassina) and the red weevil (Rhynchophorus palmarum))? We first characterize the plantation landscape with a multivariate cluster analysis which led us to identify up to nine different landscape structural types for the Macondo plantation. A mosaic of different landscape types ranging from homogeneous and simple landscapes to heterogeneous, diversified, and connected landscape types. Second, we performed an NMDS ordination to show similarities among the landscape structural types, land cover, and pest occurrence. Our results show that the integration of local ecosystems such as forests and water bodies improves landscape connectivity and suppresses the abundance of the two main oil palm pests.

Effect of soybean variety and pest management on the sustainable production

Pests are one of the limiting factors in increasing soybean production. Pest control carried out by farmers using pesticides is feared to threaten the sustainability of soybean production in Indonesia. This study aimed to identify the effect of different pest management systems and various soybean varieties on pest population dynamics, abundance and diversity of natural enemies, plant damage, and soybean production. A split plot design with three replications was applied, where the main plot was pest management systems i.e. (1) control (which received neither chemicals nor integrated pest management), (2) chemical control, and (3) integrated pest management, and the sub-plot was soybean varieties i.e. (1) Anjasmoro, (2) Demas 1, and (3) Dering 1. Results indicated that variety affects pest diversity and abundance, however, it affected leaf damage, pod damage, and production. The pest management systems influenced the diversity and abundance of pests and natural enemies, plant damage, and production. Interaction between variety and pest management system affected plant damage. We conclude that the use of resistant varieties combined with integrated pest management could reduce plant damage, maintain the natural enemy population, and optimize soybean production.

A comparison of candidate banker plants for management of pests in lettuce.

Agricultural systems are often lacking in resources for natural enemies. Providing alternative prey can help natural enemies persist through periods of low pest abundance, although this approach has been rarely commercially implemented in open field crops. In this study, we tested the potential of eight plant species to provide alternative prey to natural enemies in lettuce fields over a 2-yr period. Results showed that the tested plants would not act as sources of the lettuce aphid Nasonovia ribisnigri Mosley (Hemiptera: Aphididae), the primary lettuce pest. Of the banker plants tested, barley contained high numbers of non-lettuce aphids and appeared to provide reliable habitat for hoverfly larvae. However, lettuce aphids were present on lettuce early in the season, and may have dwarfed any effects of nonlettuce aphids on natural enemy populations. Numbers of hoverfly larvae were also high in lettuce, but did not appear to track numbers of non-lettuce aphids on banker plants. In contrast, numbers of lacewing larvae were highest on plants containing high numbers of non-lettuce aphids, and predatory hemipterans appeared to be associated with numbers of thrips on banker plants. Although barley showed promise as a source of alternative aphids, it did not appear to improve pest control in the adjacent crop.

Effect of crop rotation, pesticides and fertilizers on the abundance and taxonomic composition of spring wheat pests

Relevance. One of the main factors in obtaining high yields of high-quality wheat is its protection from pests. Their taxonomic composition and abundance vary depending on the area of research, the phase of vegetation and agricultural technology — variety, predecessor, level of mineral nutrition, use of insecticides, etc. In connection with the above, the purpose of the research was to analyze the response of pests in intensification in the conditions of the steppe zone of the Krasnoyarsk Territory.Methods. The experimental part of the work was carried out in 2017–2022 on the basis of the GSU of the Krasnoturansky district. 13 varieties of soft spring wheat were considered as objects of research. GSU Krasnoturansky district is located in the steppe zone of the Krasnoyarsk Territory. The experiment was laid according to the method of state variety testing. As a fertilizer, based on the results of agrochemical analysis, ammonium nitrate (34.4%) 70 kg a. i. was used. per ha. According to the results of soil analysis, the introduction of phosphorus and potassium was not required. Predecessors of steam and grain. During the growing season, the crops were treated with modern means of protection.Results. It was found that the number of pests on the fallow predecessor was 1.42 times higher than on the grain one. When ammonium nitrate is introduced, the number of insects increases by 1.33 times compared with the unfertilized predecessor. In the steppe zone of the Krasnoyarsk Territory, the most common pests of soft spring wheat are wheat thrips, swedish fly and bread flea.

Environmental context and herbivore traits mediate the strength of associational effects in a meta‐analysis of crop diversity

Abstract Crop diversification offers a promising solution to meet expanding global food demands while maintaining ecosystem services. Diversification strategies that use mixed planting to reduce pest damage (e.g. intercropping), termed ‘associational effects’ (AE) in the ecological literature, can decrease (associational resistance) or increase (associational susceptibility) herbivore abundance on a focal plant. While application of AE to agroecosystems typically reduces pest abundance, the range of outcomes varies widely. We conducted a meta‐analysis using 272 estimates of insect herbivore abundance on crops neighbored by a conspecific or heterospecific from 44 studies undertaken on six continents. We focus on four agricultural crops well represented from sites across the globe to test hypotheses related to understanding how herbivore traits (diet breadth, feeding guild, origin), plant traits (crop type, phylogenetic distance to neighbour) and environmental context (climate, experimental design) contribute to variation in the outcomes of AE. Overall, bicultures provided a strong reduction of insect abundance on the focal crop. Climate and interactions between herbivore traits, particularly diet breadth and origin, and plant traits or environmental context mediated the strength of AE. Bicultures provided the strongest reductions in insect abundance at low latitudes, and this effect decreased at higher latitudes but only for insects with certain traits. Abundance of generalist herbivores and globally distributed pests tended to be most strongly negatively affected by bicultures, under certain contexts, whereas specialist herbivores and native pests were less affected by neighbours. Synthesis and application. This meta‐analysis highlights that crop diversification schemes have an overall strongly beneficial effect of reducing pest abundance. However, there was also variability in the outcomes that is determined in part by the interactive effects of herbivore traits and environmental context. The results provide guidance for incorporating beneficial ecological interactions into integrated pest management strategies.

A review on seasonal succession and management of key insect- pest infesting tomato

Tomatoes have become one of the most significant and profitable vegetable crops farmed for fresh market and processing in tropical and subtropical parts of the globe and they are an important element of our human nutrition. Tomatoes, like other vegetables, are more susceptible to insect pests and illnesses than other crops, owing to their sensitivity and softness. Insect pests are among the many causes that cause low tomato yields includes fruit borer, jassid, white fly, aphid and leaf miner. On the other hand, enough understanding about seasonal abundance of insect pests is required for the formulation and implementation of an appropriate, effective, and timely pest management approach. The current demand focuses not only on the use of various eco-friendly chemical groups, but also the employment of unique modes of action to provide sufficient control of insect pest populations. So, this work reviews and presents a pool of research on seasonal succession and management of key insect pests of tomato.

Local scale crop compositional heterogeneity suppresses the abundance of a major lepidopteran pest of cruciferous vegetables

Previous studies have recommended preserving semi-natural habitats as a strategy to promote natural enemies and reduce the abundance of agricultural pests. Such non-crop habitats, however, may increase pest abundance, causing spillover from non-crop to crop fields. A potentially more economical and attractive solution for farmers might arise if crop fields were themselves designed to aid in pest control. As part of such a strategy, we examined whether increasing crop compositional heterogeneity (i.e. the number of crop types and their evenness) and crop configurational heterogeneity (i.e. field margin length) could reduce the abundance of Pieris canidia, a major agricultural pest butterfly in several Asian countries. Adult females of P. canidia lay their eggs on cruciferous vegetables (Brassicaceae), and the emerging larvae consume the leaf tissue, causing crop damage. We surveyed adult P. canidia across 52 farmlands in south China when their abundance was at a peak in spring (April to May). Our results showed that the percentage of cruciferous crops (cabbage, oilseed rape, and pak choi) at the 100 m radius local scale was strongly positively associated with P. canidia abundance. However, crop compositional heterogeneity, also at the local scale, significantly reduced the abundance of P. canidia. Field margin type, categorized by the spatial coexistence of the most dominant cover types (sugarcane, corn, vegetables, including crucifers, and weedy vegetation), was also an important explanatory variable, with weedy patches, usually consisting of fallow cropfields adjacent to the field margins, having the highest pest abundance. These results suggest that to control pest attack by P. canidia on cruciferous vegetables, increasing crop compositional heterogeneity could be a more effective strategy than increasing configurational heterogeneity or the amount of non-crop habitat. However, research measuring crop damage by larval butterflies is necessary to confirm this hypothesis.

Avian regulation of crop and forest pests, a meta-analysis.

Birds have been shown to reduce pest effects on various ecosystem types. This study aimed to synthesize the effect of birds on pest abundance, product damage and yield in agricultural and forest systems in different environments. Our hypothesis is that birds are effective pest regulators that contribute to a reduction in pest abundance, enhancement of yield quality and quantity and economic profit, and that pest regulation may depend on moderators such as the type of ecosystem, climate, pest, and indicator (ecological or economic). We performed a systematic literature review of experimental and observational studies related to biological control in the presence and absence of regulatory birds. We retained 449 observations from 104 primary studies that were evaluated through qualitative and quantitative analyses. Of the 79 studies with known effects of birds on pest regulation, nearly half of the 334 observations showed positive effects (49%), 46% showed neutral effects, and very few (5%) showed negative effects. Overall effect sizes were positive (mean Hedges' d=0.38 ± 0.06). A multiple model selection retained only ecosystem and indicator types as significant moderators. Our results support our hypothesis that there is a positive effect of avian control of pests for each analyzed moderator and this effect was significant for both ecological and economic indicators. Avian regulation of pests is a potential effective approach for environmentally friendly pest management that can reduce pesticide use regardless of the context of implementation. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Crop-specific effectiveness of birds as agents of pest control

Ecosystem services provided by the natural enemies of agricultural pests can increase crop yield in low intensity agricultural systems. However, these services are highly variable, and trade-offs may exist between harmful and beneficial species. An increasing proportion of New England farms have adopted farming practices that retain extensive native vegetation, and prior research has shown these practices support native bird populations. To determine the pest control services provided by birds on low-intensity New England farms, we compared pest populations and leaf damage on crops where birds were excluded to those where they were not. We found that pest abundance was higher on brassica and cucurbit crops within exclosures than on control plants without exclosures, suggesting the presence of birds reduced pest numbers on these crops. In contrast, pest numbers were lower on solanaceous crops within exclosures, suggesting birds may be consuming other natural enemies of pests on these crops. Leaf damage was also lower where birds were present in all three crop types, though not significantly so in brassica crops. Our results show that growers in can improve natural biological control of brassica and cucurbit crop pests by enhancing bird communities near these crops, while effects may be less predictable in solanaceous crops.

Intercropping shifts the balance between generalist arthropod predators and oilseed pests towards natural pest control

Pest management in intensive crop production currently underutilizes natural biological control, and frequently results in pesticide application. Intercropping modifies physical and ecological conditions in the field and alters the predator-prey dynamics to potentially benefit generalist arthropod predators. We investigated the assemblages of ground-dwelling arthropod predators and crop pests of spring turnip rape (Brassica rapa L. ssp. oleifera) and faba bean (Vicia faba L.) in a replicated two-year field experiment. Pitfall traps and pan traps were used to sample arthropod predators and pests. Arthropod assemblages were compared between intercropping and monocropping systems to illustrate the changes. Intercropping was associated with lower abundance of turnip rape pests compared with monoculture. The total abundance of ground-dwelling predators did not differ between cropping systems. Carabid beetles (Coleoptera: Carabidae) and spiders (Araneae) were the dominant generalist predator taxa. Faba bean monoculture supported the highest abundance of harvestmen (Opiliones) and the lowest abundance of ants (Hymenoptera: Formicidae). The turnip rape monoculture had the highest abundance of spiders in the first year but not in the second. The abundance and species assemblage of carabids indicated a response to season progress but not to cropping system. The abundance of turnip rape pests reflected host crop proportions in each cropping system. Because the cropping method had no significant impact on predator abundance, intercropping potentially facilitated natural biological control resulting from a higher ratio of ground-dwelling predators to pests. Differential within-season dynamics among abundant predator taxa also implied a temporal shift in predation characteristics, and hence, vulnerability of crop production to pest injuries. To utilize natural biological control more effectively at the field scale, intercropping with no shared pests between crops, minimal chemical pest control, and heterogeneous agricultural landscapes are needed.

Attractiveness of synthetic pheromones for stem pests monitoring in pine stands in Belarus

Dynamics of pine stands dieback in 2016‒2021 in the forest fund of Belarus is presented. The area of clear sanitary cuttings was 112.3 thousand hectares.The results of field tests on attractiveness assessment of Belarusian synthetic pheromones “IPSVABOL V”, “IPSVABOL SH”, “MONVABOL” using barrier traps for monitoring the abundance of sharp-dentated (Ips acuminatus G yll.) a nd s ixtoothed (Ips sexdentatus Boern.) bark beetles and longhorn beetles (Monochamus spp.) in pine stands are presented. During insect abundance monitoring in pine stands, it was found that the synthetic pheromone “IPSVABOL V”, “IPSVABOL SH” and “MONVABOL” are highly attractive to beetles of the sharp-dentated, six-toothed bark and longhorn beetles of the genus Monochamus when monitoring their abundance in pine stands. It was revealed that the first generation flying of the sharpdentated and six-toothed bark beetles are the most widespread and higher by 1.8‒4.5 and 3.8‒5.1 times of the second generation flying of these stem pests, respectively.For the first time, scales for assessing the abundance and methods for pheromone monitoring of the sharp-dentated and six-toothed bark beetles, and longhorn beetles (Monochamus spp.) have been developed. The use of the developed scales in forest protection practice makes it possible to quickly control the abundance of these stem pests and their distribution in pine stands for appointment of forest protection measures.