Insect Population Density Research Articles

Dynamic alterations and ecological implications of rice rhizosphere bacterial communities induced by an insect-transmitted reovirus across space and time

BackgroundCereal diseases caused by insect-transmitted viruses are challenging to forecast and control because of their intermittent outbreak patterns, which are usually attributed to increased population densities of vector insects due to cereal crop rotations and indiscriminate use of pesticides, and lack of resistance in commercial varieties. Root microbiomes are known to significantly affect plant health, but there are significant knowledge gaps concerning epidemics of cereal virus diseases at the microbiome-wide scale under a variety of environmental and biological factors.ResultsHere, we characterize the diversity and composition of rice (Oryza sativa) root-associated bacterial communities after infection by an insect-transmitted reovirus, rice black-streaked dwarf virus (RBSDV, genus Fijivirus, family Spinareoviridae), by sequencing the bacterial 16S rRNA gene amplified fragments from 1240 samples collected at a consecutive 3-year field experiment. The disease incidences gradually decreased from 2017 to 2019 in both Langfang (LF) and Kaifeng (KF). BRSDV infection significantly impacted the bacterial community in the rice rhizosphere, but this effect was highly susceptible to both the rice-intrinsic and external conditions. A greater correlation between the bacterial community in the rice rhizosphere and those in the root endosphere was found after virus infection, implying a potential relationship between the rice-intrinsic conditions and the rhizosphere bacterial community. The discrepant metabolites in rhizosphere soil were strongly and significantly correlated with the variation of rhizosphere bacterial communities. Glycerophosphates, amino acids, steroid esters, and triterpenoids were the metabolites most closely associated with the bacterial communities, and they mainly linked to the taxa of Proteobacteria, especially Rhodocyclaceae, Burkholderiaceae, and Xanthomonadales. In addition, the greenhouse pot experiments demonstrated that bulk soil microbiota significantly influenced the rhizosphere and endosphere communities and also regulated the RBSDV-mediated variation of rhizosphere bacterial communities.ConclusionsOverall, this study reveals unprecedented spatiotemporal dynamics in rhizosphere bacterial communities triggered by RBSDV infection with potential implications for disease intermittent outbreaks. The finding has promising implications for future studies exploring virus-mediated plant-microbiome interactions.2AL1xEb7k2nunVBmbuNCsVVideo

Correlation Analysis of Sitophilus oryzae (Linnaeus) Real-Time Monitoring and Insect Population Density and Its Distribution Pattern in Wheat Grain Piles

The traditional manual sampling method for detecting stored grain insect pests is labor-intensive and time-consuming, often yielding non-representative samples. However, to achieve more accurate monitoring, it is necessary to understand the distribution patterns of different insect pests within grain silo and their correlation with monitoring and sampling data. This study aimed to assess the population density and distribution of Sitophilus oryzae (rice weevil) in bulk wheat grain to predict insect dynamics effectively. Utilizing a probe trap in a wheat silo, adult insects were tracked across different population densities. The traps recorded captured pests, alongside temperature and humidity data. The correlation analysis revealed that rice weevils were active throughout the silo but less prevalent at the bottom, with the highest distribution near the upper surface. Temperature and humidity significantly influenced their activity, particularly within the 22 °C to 32 °C range. Higher population densities correlated with increased relative humidity, impacting weevil activity. Trapping data aligned with overall population density changes in the silo. This study will provide an accurate assessment of the population density of adult rice weevils in grain silos based on temperature changes in the upper part of the grain silo.

A Comprehensive Survey of Population Ecology in Insects

Population ecology focuses on studying populations and their relationship with the environment, including parameters such as birth, death, migration, density, and age distribution. Population ecology involves laboratory work, field observations, and the use of mathematical and statistical models to study groups of organisms. By studying populations, researchers gain insights into population dynamics, growth, distribution, density, and age structure. Insects play a vital role in population ecology by influencing ecosystems and human societies. They contribute to ecological processes such as decomposition, pollination, and nutrient cycling. In addition, some insects produce valuable substances, and predatory insects help control pests. Understanding population dynamics and interactions is crucial for conserving and managing natural resources effectively. Population ecology is a branch of ecology that focuses on studying the lives of organisms within populations and their interactions with the environment and other populations. Different species have developed various strategies to deal with organisms of their species or other species. Some species compete directly with individuals of the same species, while others form social groups and cooperate to secure resources. Population ecologists examine complex interactions between organisms and their environment, which lead to different selective pressures for animals that compete with individuals of the same species. Humans, for example, have been successful in part because of their social nature and ability to cooperate to obtain vital resources. The field of population ecology seeks to answer questions about the carrying capacity of the environment, the optimal population size, the causes and mechanisms of population growth, and population distribution. Insects play a significant role in biodiversity, accounting for 64% of the world's biodiversity. They have diverse functional roles in ecosystems, including herbivores, hunting, parasitism, decomposition, and pollination. Various factors influence the number, population, and survival of insects, including insect diversity, abundance, evolution, and habitats. Population ecology studies these factors to understand the survival and current population dynamics of insects. The distribution of insects is an important indicator of species diversity and is influenced by factors such as time, conditions, and food resources. For example, the leopard beetle Cicindela longilabris is found at higher latitudes and elevations, with populations ranging from northwestern Canada to the coastal states of eastern Canada. Ecologists believe that historical climate changes, such as the last Ice Age, have influenced the current distribution of this species. In studying insect populations, ecologists use sampling techniques to estimate population size and abundance. Statistical methods, such as the rarefaction method, are employed to compare species abundance in different areas and estimate the number of species present in a sample. Understanding changes in insect population density over time is important, and ecologists study population life cycles and population explosions to gain insights into these fluctuations. By comprehending and predicting changes in insect populations, ecologists can mitigate potential damage and obtain valuable information about insect abundance. Certain species of locusts, including the desert locust, migratory locust, tree locust, and Australian locust, experience periodic population eruptions. In South America, various species of desert locusts are also significant pests. Climatic factors play a significant role in the formation and migration of locust swarms. Locust eggs can remain dormant in the soil until rain triggers their hatching. The rainy season is optimal for egg development, and rainfall also promotes the growth of green plants, which serve as food for nymphs and adult grasshoppers. The El Nino phenomenon, characterized by periodic changes in flight patterns, has a significant impact on locust populations, causing substantial damage every few years. Satellite imagery is commonly used to identify locust groups by detecting areas of new plant growth following rain. Once the nymphs have exhausted their food sources, the locust swarm enters the migratory phase, guided by wind direction. These swarms can persist for months or even years under favorable weather conditions, but population declines occur when dry weather or significant temperature drops occur. In conclusion, population explosions in migratory locusts are primarily influenced by density-independent factors like climate change, rather than density-dependent factors.

Research status of insect infestation of Chinese medicinal materials during storage

During the storage process, Chinese medicinal materials are susceptible to insect infestation due to their own nature and external storage factors. Infestation by insects can have varying impacts on the materials. In mild cases, it affects the appearance and reduces consumer purchasing power, while in severe cases, it affects the quality, reduces medicinal value, and introduces impurities such as insect bodies, excrement, and secretions, resulting in significant contamination of the medicinal materials. This study reviewed the rele-vant factors influencing insect infestation in Chinese medicinal materials and the compositional changes that occur after infestation and summarized maintenance measures for preventing insect infestation. Additionally, it provided an overview of detection techniques applicable to identifying insect infestation during the storage of Chinese medicinal materials. During the storage process, insect infestation is the result of the combined effects of biological factors(source, species, and population density of insects), intrinsic factors(moisture, chemical composition, and metabolism), and environmental factors(temperature, relative humidity, and oxygen content). After infestation, there are significant changes in the content of constituents in the medicinal materials. By implementing strict pre-storage inspections, regular maintenance after storage, and appropriate storage and maintenance methods, the occurrence of insect infestation can be reduced, and the preservation rate of Chinese medicinal materials can be improved. The storage and maintenance of Chinese medicinal materials are critical for ensuring their quality. Through scientifically standardized storage and strict adherence to operational management standards, the risk of insect infestation can be minimized, thus guaranteeing the quality of Chinese medicinal materials.

Evaluation of Sticky Traps and Baits in Control of Melon Fly, Dacus frontalis Becker on Melon

The Dacus frontalis Becker is known species, being an agricultural pest. It has been attacked Cucumis melo L. Sticky traps and baits have been used as one of effective integrated control methods to monitor different types of insects. It is way to know population density of insects. For sticky traps, the average number of adults of insects caught in yellow, Transparent, blue and red traps was 15.72, 9.50, 4.67, 3.17 adults\\ trap\\ six weeks respectively. However, for baits, results have been recorded that average numbers of adults caught in traps were 13.67, 10.00, 9.17, 7.75, 50.6, 2.50 adult/trap. The results have been recorded that average numbers of adults caught for bait traps were 38.34, 32.67, 28.33, 17.26, 17.84, 7.84 adult/trap. The effectiveness of yellow traps and Transparent traps has been proven to attract large numbers of adults, as their use on farms is easy, easy to use, low cost, and helps in rationing the use of pesticides, especially if they are expensive. Furthermore, they help us predict the time of appearance of the insect in melon to give a correct time.

Investigation of insect population density, species composition and associated losses in chickpea seeds stored on farms in Ethiopia

This survey aimed to investigate the extent of insect infestations, associated losses, and insect species abundance in farm-stored chickpea seeds across five chickpea growing districts in Ethiopia. Despite being the largest producer, consumer, and exporter of chickpea in Africa, insect pest infestations have caused significant losses to Ethiopia's chickpea industry. Results showed that Callosobruchus chinensis (L.) was the most prevalent insect species, followed by Sitophilus oryzae (L.) and Tribolium confusum (J. du Val). The insect pests infested both local and improved chickpea varieties, and traditional containers and polypropylene bags were used for storage. The percentage of insect-damaged seed ranged from 4.61% to 14.48%, while the seed weight loss ranging from 1.13% to 4.55%. The range of seed germination percentages was from 65% to 88%, with a mean rate of 71%. These losses significantly affect the market value of the crop as grain and its use as seed, affecting farmers' income and food security. Therefore, it is crucial to develop effective solutions to prevent the loss of farm-stored chickpea in Ethiopia.

Variations in the Biological and Ecological Attributes of Insects Due to Climate Change: A Review

Climate change is causing a shift in long-term weather patterns and altering parameters such as temperature, atmospheric CO 2 , and precipitation patterns. It is likely to be an indirect effect of greenhouse gases and their enhancement in the atmosphere largely induced by human activities. As poikilothermic animals, insects are highly dependent on environmental conditions, particularly temperature, which affects various aspects of their life. Climate change have a direct impact on insect pests by affecting their population dynamics, diurnal activity, growth rate and diapause. It may lead to a range expansion, increased overwintering survival, more generations per year, elevated risk of invasive insect species and insect-borne plant diseases, and changes in their interactions with host plants and natural predators. Indirectly, changes in climate can modify host plants and competitors, further complicating the effect on insect biology and phenology. Impact of elevated CO 2 levels on their host plants can affect growth rates, fecundity, and population densities of insects. Altered precipitation patterns, such as droughts and floods, affect insect survival and diapause. Further, there is significant implications of climate change on different aspects of insect ecology, including insect distribution, behavior, and communication. The climate changes are predicted to alter the geographic ranges and migration behavior of insect species, creating new ecological niches and removing low-temperature barriers. These changes can threaten food security and increase the latitudinal and altitudinal range of crop pests. It also affects natural enemies, which can decrease the plant defense system against insect pests. Additionally, climate change can affect pheromonal communication, including production to behavioral response, in insects that rely on long-range chemical signals for communication. The review paper highlights the potential impacts of climate change on insect biological, phenological and ecological aspects.

Current Problems of Forest Protection (25–27 October 2022, Katowice Poland)

Forestry is one of the sectors particularly affected by the threats posed by changing climatic conditions. This is reflected in the deterioration of the health status of stands due to the synergistic effect of numerous abiotic and biotic factors. Current forest health problems are due to dynamic, negative changes in the forest environment. While the amount of precipitation remains at a similar level, its distribution varies throughout the year and, in particular, the lack of soil moisture during the growing season leads to the weakening of trees, including the main forest-forming species in Poland such as Pinus sylvestris. The weakening of trees, in turn, leads to species of insect pests that were previously considered secondary becoming primary pests, such as Ips acuminatus. It is likely that weakening of trees also favours increased occurrence of parasitic plants such as Viscum album ssp. austriacum or Loranthus europaeus. Infestations of the hemiparasitic, xylem-secreting pine mistletoe are of great interest because they are spreading rapidly throughout Europe. Drought in forests is not only a long-term water shortage, but also a situation in which plant-fungal relationships are disrupted. Reduced water availability leads to a number of negative changes in the soil and the mycobiota that live there, affecting entire ecosystems. The effects of climate change and increased international trade are leading to the spread of pathogenic fungi and other harmful organisms whose range was previously restricted to the south of our continent. Unfavourable abiotic and biotic factors leading to weakening of oak stands in the western part of Poland have resulted in activation of new pests like Mediterranean oak borer. Intensification of transport and shortening of its duration, as well as climatic changes, favour the introduction of various organisms, including bark beetles (Scolytinae). In Poland, cyclic insect outbreaks are one of the most important problems in forest protection. Developing methods to monitor, prevent outbreaks and control the density of insect populations below harmful levels can be a challenge to consider. Finding an innovative system for applying insecticides to control spruce bark beetle could also be an interesting solution, where insects attracted to pheromones die after contact with the insecticide. Contact with the insecticide has a dual effect: either directly when the tree is treated, or when the bark beetle attempts to invade the tree. Opportunities for the use of biostimulants in forestry and is an attractive way to regenerate plants after negative stressors such as frost, drought or damage caused by improper use of pesticides, as well as the negative effects of diseases and pests. It acts indirectly by stimulating leaf, stem and root development and improving nutrient uptake. The effects of chemical treatments on fungal biodiversity in forests should be studied using powerful molecular tools such as NGS.

Effect of cucumber varieties and some chemical pesticides on the population density of Bemisia tabaci

The current study was conducted to evaluate the sensitivity of three varieties of water cucumber Syrian, Dutch, French and the effectiveness of three insecticides Joker, Harvest, Chase against the tobacco Bemisia tabaci Meza Tabachi in Hawija area - Kirkuk governorate. In the fall from August to December 2020, and the results showed that the Syrian variety made the varieties resistant to Bemisa tabaci, as it reduced the insect population density to 32.40 adult insects/10 leaves and 28.75 nymphs / 16. cm2 in. As for the French and Dutch cultivars 44.85, 44.38 adults / 10 leaves and 40.77 and 39.95 nymphs / 16 cm2 respectively with insecticidal effect on the insect, the results showed that the joker was the best. More effective in reducing insect populations, where the average density was 32.6 insects/10 leaves and 33.39 nymphs/16 cm2 compared with Shays and Harves, where the average population density was 41, 3 and 47.72. adult. /10 leaves and 36.39 and 39.69 nymph 6 cm2. The lowest population density of insects was recorded in the Syrian cultivar treated with Joker pesticide, with an average of 24.54 insects/10 leaves and 27.26 16 cm nymphs. All pesticides showed better efficiency in reducing insects. One day of spraying, then its efficiency began to decline after the third and seventh days of spraying, while the lowest population density of nymphs was recorded after the seventh day of spraying with pesticides, and the lowest population density was 24.52 insects/10. Leaves and 9.81 nymphs/16 cm2 after the second spray of pesticides compared to the previous period and the first spray with an average population density of 53.91, 33.45 adults/10 leaves and 48, 53 and 21.07 nymphs/16 cm2 respectively. The Joker was marked by low adult population density after 1 and 3 days for each of the first sprays, so what is it? On average, after 1 and 3 days of spraying 3.21, 4.77, 2.76, 3.76 insects/10 leaves, respectively, and for spraying days of nymphs 8.66, 4.88 and 3.88 nymphs were counted. / 16 cm2 each, respectively

Aggregative oviposition varies with density in processionary moths—Implications for insect outbreak propensity

AbstractIn gregarious insects, groups commonly originate from females laying eggs in masses and feeding groups are established as soon as larvae hatch. Some group‐living insect species may aggregate beyond the individual parent level, such that offspring from two or more egg masses develop within a common resource.Here we show that aggregative oviposition can vary with population density at oviposition and possibly be an important factor in outbreak dynamics of phytophagous insects.We analysed density data with respect to egg mass aggregation for two species of pine processionary moths,Thaumetopoea pinivora(in Sweden 2005–2019) andT. pityocampa(in Spain 1973–1991). Both species lay their eggs in egg masses and feed in groups. During the study periods, insect population density for both species varied by at least an order of magnitude.The two species showed strikingly similar patterns of egg mass aggregation. Egg masses were overdispersed at high population density, with few trees showing a high load of egg masses.Our data suggest that aggregative oviposition can be important in explaining the previously documented higher propensity for outbreaks in insects laying eggs in clusters, compared with those laying individual eggs.

Studying the effect of environmental conditions in the seasonal abundance of lesser date moth (Batrachedra : Amydraula : Meyrick) on date palm, Phoenix dactylifera L. in Central and Southern Iraq

A field study was conducted for the 2019/2020 season, which included a field survey to determine the infestation percentages and determine the sensitivity of some date palm varieties to the infestation with the lesser date moth (B.amydraula M.). Besides, determining the date of insect appearance and its population density is based on temperatures, relative humidity, and thermal accumulation. The study showed that infestation with the lesser date moth includes all areas planted with palm trees and the infestation percentages range between medium and severe, especially in dense orchards, and according to the prevailing environmental conditions. Basra Governorate / Abu Al-Khaseeb district gave a severe infection in the total infestation percentage of 67.00%, while the lowest infestation percentage was recorded in Babylon Governorate, Al-Madhatia district, at a percentage of 17.66 %, which considered a weak infection. The study also gave a clear indication that all date varieties were infested with lesser date moths at varying percentages, where the Al - Zahdi cultivar recorded the highest infestation percentage of 58.71%, while Al - Halawi cultivar recorded the lowest infestation percentage amounted to 39.97%. The study recorded the first appearance of the insect adults at the beginning of the second week of March in both Basra and Babylon governorates, with a population density of (2.80, 2.80) insect/in2 respectively at an average temperature (14.26, 15.20) ºC, respectively, and average humidity of (49.86, 51.67) % respectively. The study showed that the insect has three overlapping generations during the year, starting from the beginning of March to the beginning of March of the next season, as the duration of the first and second generations was one month each, while the duration of the third generation extends to approximately nine months. The insect has three peaks in which the insect population density increases significantly. In Basra, the increase reached its peak at the beginning of the second week of April and during the second week of May and June, with a population density of (7.71, 7.39 and 6.88) insect/in2 respectively, and an aggregate temperature of (445.20, 665.52 and 814.65) thermal units, respectively. However, in Babylon, the seasonal abundance of the insect reached its peak at the end of the first week of April and the second week of May and during the third week of June, with a population density of (6.71, 6.40, and 6.60) insect/in2 and a thermal accumulation of (358.08, 418.56 and 586). 08) thermal unit.

Does grape leafhopper Arbordia hussaini (Hemiptera: Cicadellidae) effect on chlorophyll content of grape leaves?

The leafhopper Arbordia hussaini is a phloem feeding pest of the grape leaves causing a drop in chlorophyll levels in the grape leaves, which decreases photosynthesis and causes drying of the leaves depend on the population density of insects and found in various grape varieties growing around the world. The direct effects of A. hussaini on biomass dynamics, particularly the chlorophyll content of grapevine leaves, are investigated in this study. the high population of A. hussaini were 19.33 insect adult per grape leave in the first of September, while the low density of A. hussaini was 0.11 insect adult per grape leave at the end of December that trapped in blue sticky trap. The high density of leafhopper was recorded on the variety of Kamali followed by the variety of Halawani and Faranci. Chemical analysis of the chlorophyll content between the uninfested and infested grape leaves with the grape leafhopper showed decreasing of chlorophyll content and has been given 19.03 and 15.11 mg/L of the Halawani variety for the uninfested and infested leaves, respectively. Whereas, th mean of chlorophyll content of uninfested and infested leaves was 24.63 and 18.85 mg/L for Faranci variety, respectively. Moreover, the comparession of chlorophyll content between uninfested and infested Kamali leaf variety was 23.69 and 12.30 mg/L, respectively. Finally, depending on the degree of the attack, the grapevine response to A. hussaini infestation that affects on grape leaves and photosynthesis. This research shows that leafhopper feeding on tree sap has a significant direct impact on the chlorophyll content of grape leaves.

The impact of the protein-carbohydrate ratio in animal feed and the initial insect population density on the development of the red flour beetle, Tribolium castaneum

Progeny numbers and life parameters of Tribolium castaneum reared on a range of different animal feeds which varied in their protein-carbohydrate ratios (corn starch; corn feed flour; wheat bran; soybean meal; corn gluten; soy protein concentrate and soy protein isolate), four initial (population) densities (1, 2, 5 and 10 insect pairs) were evaluated. Adult insects were kept for seven days on a range of different diets to feed and oviposit before they were removed. After removing the adults, the emerging progeny were examined. The study found T. castaneum offspring could not develop on a carbohydrate-rich diet (corn starch) and on protein-rich diets (corn gluten, soy protein concentrate and soy protein isolate). Soy isolate showed a high, possibly insecticidal effect on parents. The fastest total development (egg to adult) (23.25–23.88 days, depending on the initial density), the highest offspring number (111.63–324.13) and the highest offspring body mass (1.38–1.73 mg) were recorded in wheat bran, while the slowest egg to adult development (35.13–37.88 days), the lowest offspring number (25–29) and the lowest offspring mass (1.04–1.48 mg) were recorded in soybean meal. The higher initial densities caused the eclosion period to be prolonged, reductions in female productivity and in offspring body mass on all diets. Initial density interacted differently with diet type in terms of offspring number, so as the density rose, the number of offspring in wheat bran and corn feed flour increased, while in soybean meal it remained low at all initial densities. This research gives us a better insight into the development of T. castaneum in animal feed that can help us to improve existing pest management in a way of finding a better solution to store products based on their susceptibility to this storage pest.

The effects of mepiquat chloride (DPC) on the soluble protein content and the activities of protective enzymes in cotton in response to aphid feeding and on the activities of detoxifying enzymes in aphids

BackgroundMepiquat chloride (DPC) enhances the resistance of cotton plants, and it is widely used as a growth regulator. DPC can stimulate photosynthesis, stabilize the structure of cotton leaves, and affect population reproduction and energy substances in Aphis gossypii Glover (cotton aphids), but interactions between DPC and cotton aphids remain unclear. In this study, we analyzed the physiological responses of cotton to DPC, and the toxicity of DPC toward cotton aphids, before and after feeding, to explore the DPC-induced defense mechanism against cotton aphids.ResultsMeasurements of protective enzyme activity in cotton showed that the soluble protein contents, peroxidase (POD) activity, and catalase (CAT) activity in cotton treated with different concentrations of DPC were higher than in the control. Superoxide dismutase (SOD) activity was higher than that of the control when the concentration of DPC was < 0.1 g/L. Under aphid feeding stress, POD activity in cotton treated with a low insect population density was significantly lower than in the controls, but the reverse was true for cotton treated with a high insect population density, and SOD activity was positively correlated with population density. The activities of detoxification enzymes in field and laboratory experiments showed that DPC promoted the specific activity of glutathione S-transferase (GST) in cotton aphids, while the specific activities of carboxylesterase (CarE) and acetylcholinesterase (AchE) were decreased.ConclusionsDPC enhanced the aphid resistance in cotton by increasing the soluble protein content and the activity of protective enzymes. It also had a toxic effect on cotton aphids by increasing GST activity (the main DPC target). DPC increased the soluble protein content and protective enzymes activity in cotton under aphid stress, and thereby enhanced tolerance to cotton aphids. It conclude that DPC interferes with cotton aphids through indirect (DPC induced cotton defense responses) and direct (DPC toxicity to cotton aphids) ways, which plays a positive role in interfering with cotton aphids.

Study on sampling scheme for detecting mycotoxin during wheat storage.

Mycotoxin produced by mould is one of the most serious contamination sources in food security. Safe storage of grain has become more important to control food security. Currently, there is no officially approved or standardized sampling scheme for detecting mycotoxin in grain storage worldwide. In this study, deoxynivalenol (DON) was taken as a typical mycotoxin in stored wheat to be detected. Population density of corn weevil could not significantly increase wheat moisture, but wheat moisture was highly significantly and positively correlated with DON content (P < 0.01). Corn weevil density significantly increased the DON content in wheat. DON contamination degree was mainly distributed in the region of 14-20 cm below the surface layer of wheat. In the process of ventilation and dehumidification during the storage period, moisture of wheat decreased slightly with the extension of ventilation, but the DON content in wheat increased significantly. Combined with the analysis of ventilation, DON content in the upper layer and H1 position, where the wind direction is not easy to reach, increased significantly. Areas with high insect population density (14-20 cm below the surface layer of stored wheat) and low ventilation and high humidification (H1 position in the upper layer) should be taken as the key cutting sample areas for detecting mycotoxin during the period of grain storage. This study provides for the first time a scientific basis for the standardization of the wheat sampling scheme to monitor mycotoxin contamination during wheat storage. © 2022 Society of Chemical Industry.

The Use of Yellow Sticky Traps to Estimate He Population Density of Insects Accompanying Squash and Cucumber Plants in The Field

The research was performed in AL -Namrud district, south of Mosul city, in autumn season/ 2020 to determine the seasonal presence of insects that accompanying each of the cucumber and marrow, planted in rate 28 row. yellow sticky traps were used for the period from 19/ September until 31/ October, which were placed in the four directions (North, South, East and West) to find out the best direction for catching insects. The results showed that the two plants were infected with insects, aphid and leafhopper and white fly also cucurbit fly insect. Showed the highest average to aphid Aphis gossypi (Glover) 89,33 insect / trap on southern direction in 17/10 And on the cucumber plant. As for the leafhopper insect Empoasca desedens (Poali) showed highest average for insect 79 insect / trap on Northern direction in 31/10 to cucumber plant, While the highest average was recorded for an insect white fly 125 insect / trap on the southern direction in 19/9 on the cucumber plant. while yellow sticky traps did not succeed in Catching a large number of whole insects of the cucurbit fly Dacus ciliatus (Loew) showed highest average 1.33 insect / Trap on the Northern direction in 31/10 on marrow plant.

Faunistic composition of hymenopteran parasitoids in cultivation of Eucalyptus urophylla S.T. blake and adjacent areas of Seasonal Semi-deciduous Montana forest situated in the Semi-arid State of Bahia, Brazil

Hymenopteran parasitoids are insects that play a fundamental role in ecosystems as they reduce the population density of insects that are considered pests in monocultures. However, little is known about the fauna in association to the eucalyptus trees in comparison to adjacent native vegetations. Therefore, this study was aimed to determine the fauna of parasitoid wasps that occur in a commercial plantation of Eucalyptus urophylla S.T. Blake, as well as in native forest and capoeira environments in the plateau of Conquista, Bahia, a semiarid region of Bahia. The study was conducted for two consecutive years with monthly monitoring using five Malaise traps. The collected insects were sorted and identified at the family level. The faunal indices referring to the families of each area were studied by evaluating the frequency, species richness, shannon diversity and equitability. In total, 5,899 individuals were collected, which were distributed in 24 families and eight superfamilies. The most abundant families were Braconidae, Ichneumonidae and Bethylidae. Capoeira and eucalyptus trees showed greater similarity and equitability when compared to the rest of the forest. Given the diversity of Hymenopteran parasitoid families found in the area, it was concluded that the maintenance of native vegetation environments is important, even at the initial stage of succession.

Spatial and Temporal Variation in Stored-Product Insect Pest Distributions and Implications for Pest Management in Processing and Storage Facilities

Abstract Insect infestations can result in a damaged or destroyed product, costing producers and retailers millions of dollars annually. Postharvest insects move through space searching for mates, food, and shelter. Movement of product, sanitation activities, and insecticide applications also drive their spatial distribution patterns. Determining spatial distributions and population density of insects provides important information to develop targeted and cost-effective management programs. Monitoring data collected using traps to capture insect pests have provided information under a range of conditions: in bins of grain, grain elevator silos and their immediate environment, milling and processing facilities, commercial warehouses, and retail stores. In evaluating available data, we identified key influences that may be leveraged to increase the impacts of future monitoring schemes. Species-specific locations of infestation were common among stored product insect pests and seasonal variation was highly influential in population growth patterns. Competition among different species also drives spatial and temporal distributions and overlap among species is rare. Vertical distribution of insects was common in bins, elevators, and silos. More insects were often found in the receiving and storage areas of mills and processing facilities and insects often migrated into facilities from surrounding natural reservoirs. Previously stored grain and spillage can also harbor insect populations, which also reinforces the need for sanitation in and around stored grain products. Continued monitoring research will provide information to develop predictive tools which will use behavioral patterns to further our understanding of these insect pests within these unique facilities and circumstances.

How to Count Bugs: A Method to Estimate the Most Probable Absolute Population Density and Its Statistical Bounds from a Single Trap Catch.

Simple SummaryThe importance of conservation and pest management programs cannot be overstated as climate change, loss of biodiversity, and biological invasions are on the rise. Such programs often rely on traps for population detection and monitoring, assigning management and conservation tactics, and evaluating treatment efficacies. In this paper, we propose a universal method for any insect trap system to estimate the most probable absolute population density and its statistical bounds from a single trap catch. This approach will help take insect detection and monitoring to a new, rigorously quantitative level.Knowledge of insect population density is crucial for establishing management and conservation tactics and evaluating treatment efficacies. Here, we propose a simple and universal method for estimating the most probable absolute population density and its statistical bounds. The method is based on a novel relationship between experimentally measurable characteristics of insect trap systems and the probability to catch an insect located a given distance away from the trap. The generality of the proposed relationship is tested using 10 distinct trapping datasets collected for insects from 5 different orders and using major trapping methods, i.e., chemical-baited traps and light. For all datasets, the relationship faithfully ( describes the experiment. The proposed approach will take insect detection and monitoring to a new, rigorously quantitative level. It will improve conservation and management, while driv-ing future basic and applied research in population and chemical ecology.

Life Table of Rhodobium porosum on Rose Cultivars in Subsurface 'Ebb and Flow' Irrigation System

Fertilization is a limiting factor in plant development and indirectly affects the population density of phytophagous insects. This study tested the performance of the aphid Rhodobium porosum (Hemiptera: Aphididae) on three rose cultivars exposed to two nutrient solutions in subsurface 'ebb and flow' irrigation systems in greenhouse. The performance of R. porosum was determined by means of the life table and fertility. Both cultivar and fertilization affected many life history and population traits of the aphid. The lower insect fertility and survival were observed in the nutrient solution usually recommended for fruit-type vegetables and on the 'Tineke' rose cultivar, because this combination caused lower net reproductive rate R0 (0.52 female), finite rate of increase λ (0.9469 female/day), innate capacity to increase in number rm (-0.0516 female/female/day), as well as longer time interval between each generation T (16.62 days). The lowest performance of the R. porosum on 'Tineke' rose cultivated in the nutrient solution 1 suggests that this seems to be the best combination to reduce problems with aphid attack in soilless rose cultivation.