Pest Of Wheat Research Articles

Effect of soil treatment on pest infestation and crop disease distribution in black soil fields with short rotation crops

We have established the influence of four tillage systems on pest distribution and development of diseases in cultivated cereals during three-year research (2017-2019) in the field stationary of the Bila Tserkva National Agrarian University, Ukraine (chernozem grain sprouting with five-course rotation). The population of turnip moth in winter wheat, spring barley, and soya was the highest under application of disk tillage, the lowest – under moldboard tillage. The moldboard treatment limited while the beardless and disk treatments stimulate the development of beet webworm in the cereal crops. The number of pests in soya, winter wheat, spring barley, and maize was higher under combined soil treatment compared to moldboard. We recorded no significant difference in pests towards tillage systems in sunflower crops. In soya, winter wheat and maize crops, the number of wireworm was significantly higher in molded than in molded cultivation; the opposite pattern was observed in the sunflower field, while for spring barley these values were at the same level. The distribution and development of root rot in cereal crops was higher in comparison with control, but this difference was insignificant in spring barley. The development of powdery mildew in spring barley crops was almost the same for these tillage options. In cereal crops, septoriosis lesions were almost at the same level in case of moldboard and combined tillage. Significant deterioration of phytosanitary condition at beardless and disk tillage resulted in significant reduction of crop rotation productivity in comparison with control. In the fields with combined and disk treatments, the productivity value was almost the same.

English

Ethiopia is the only country in Sub-Saharan Africa where smallholder wheat production meets more than 70% of the national consumption demand. Russian wheat aphid (RWA; Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae) is one of the major insect pests of wheat throughout the world including in Ethiopia. Wheat yield loss due to RWA damage in Ethiopia was estimated to be 70%. Therefore, the present study was carried out to determine the effect of integrating the potentials of the plant extracts of Neem, Azadirachta indica L. (leaf and seed) and the Entomopathogenic fungi (EPF); Beauveria bassiana and Metarhizium anisopliae against the RWA. After 7 days of applications; the combined mixture of B. bassiana with M. anisopliae caused the maximum loss (73.4%) of aphids, while the combination of Neem leaf with seed extracts recorded the least (57.82%) abundance of aphids, which were negatively affected by single and combined treatments. The lowest abundance was recorded when the aphid was treated by the combination of both B. bassiana and M. anisopliae as well as the combined mixture of Neem leaf and seed extracts. The results indicated that bio-pesticides, based on entomopathogens and botanical extracts (Neem) can be the best replacements for synthetic chemicals and caused significant reduction in survival and abundance of RWA. Therefore, they could be used as promising natural alternatives to synthetic insecticides against RWA in Ethiopia. Key words: Russian wheat aphid, Diuraphis noxia, Beauveria bassiana, Metarhizium anisopliae, Neem, efficacy.

Differential Stem Proteomics and Metabolomics Profiles for Four Wheat Cultivars in Response to the Insect Pest Wheat Stem Sawfly.

Common wheat (Triticum aestivum L.) is a global staple crop, and insect pests can impact grain yield. The wheat stem sawfly (Cephus cinctus, WSS) is a major wheat pest, and while partial resistance has been deployed by breeding for a solid-stem trait, this trait is affected by environment. Here, a proteomics and metabolomics study was performed on four wheat cultivars to characterize a molecular response to WSS infestation. The cultivars Hatcher (hollow-stem partially tolerant), Conan (semisolid-stem-resistant), and Denali and Reeder (hollow-stem-susceptible) were infested with WSS, and changes in stem proteins and metabolites were characterized using liquid chromatography-mass spectrometry. The proteome was characterized as 1830 proteins that included five major biological processes, including metabolic processes and response to stimuli, and the metabolome (1823 metabolites) spanned eight chemical superclasses, including alkaloids, benzenoids, and lipids. All four varieties had a molecular response to WSS following infestation. Hatcher had the most distinct changes, whereby 62 proteins and 29 metabolites varied in metabolic pathways involving enzymatic detoxification, proteinase inhibition, and antiherbivory compound production via benzoxazinoids, neolignans, and phenolics. Taken together, these data demonstrate variation in the wheat stem molecular response to WSS infestation and support breeding for molecular resistance in hollow-stem cultivars.

Review of the genus Eurygaster (Hemiptera: Heteroptera: Scutelleridae)of Russia.

Six species of the genus Eurygaster Laporte, 1833 are currently recorded from the territory of the Russian Federation including Eurygaster integriceps Puton, 1881, the most important pest of wheat in Russia. Determination of Eurygaster spp. to the species level remains challenging especially in the case of closely related E. integriceps, E. maura (Linnaeus, 1758), and E. testudinaria (Geoffroy, 1785). This often leads to errors in identification of these species and provides incorrect information for plant protection services. Additional features for more precise identification are discussed and a key to all species of the genus Eurygaster of Russia is provided. The key is backed up with short diagnoses of every species, original color photographs and summarized data on the distribution. Taxonomic status of E. testudinaria sinica Walker, 1867 is discussed and E. testudinaria sinica Walker, 1867 is synonymized with the nominative subspecies. Also, a key to all seven genera of Scutelleridae known from Russia is given.

Seed rates and insecticides effects on Russian wheat aphid Diuraphis noxia (Hemiptera: Aphididae) occurrence in irrigated durum wheat (Triticum durum) in the central highland of Ethiopia

The Russian Wheat Aphid (RWA) Diuraphis noxia (Kurdjumov) causes severe damage to wheat in the highlands of Ethiopia. An experiment was conducted to evaluate the effect of seed rates and insecticides on incidence of RWA and grain yield of durum wheat under irrigated filed condition at Debre Zeit Agricultural Research Center, Ethiopia, during 2017. Three insecticides (Dimethoate 40 EC, Actellic 50 EC and Highpro220EW) and one untreated check with six seed rates (75,100,125, 150,175, and 200 kg/ha) were used in split plot design with three replications. Data were collected on plant or plot basis. Data on RWA number was recorded on plant bases. Whereas, leaf rolling, chlorosis, number of deformed head, phenological stages, yield and other yield related parameters were collected on plot basis. Data were subjected to analysis of variance using SAS version 9.3. Mean separation was made using least significant test using Tukey’s HSD (Honestly Significant Difference). The seed rates and insecticides significantly affected the incidence of RWA plant damage (chlorosis), deformed heads, plant height, yield and yield components except the interaction for number of grains per head and thousand seed weight. Dimethoate 40EC and Highpro 220EW sprayed plots gave the highest grain yield and the tallest plant height. The highest grain yield was obtained from 125 kg/ha sown plots and sprayed with Dimethoate 40 EC and the lowest grain yield was obtained from the untreated check sown at the rate of 75 kg/ha. The highest number of RWA per tiller and damaged plants were recorded on the untreated plots and the lowest RWA numbers was recorded, in decreasing order, from Dimethoate 40EC, Highpro 220EW and Actilic 50EC treated plots. Untreated plots with seed rate 150 kg/ha, 175 kg/ha and 200 kg/ha sown plots significantly reduced RWA population than the others. This indicates that there is the possibility of using seed rates above 150 kg/ha to managing RWA. RWA is a serious pest of irrigated wheat in Ethiopia, causing substantial yield losses in different seasons to in irrigated wheat production. The overall results indicated that sowing at a seed rates of 125 kg/ha and spraying Dimethoate 40EC gave the highest yield grain and can be recommended for RWA management under irrigated condition.

Entomopathogenic Fungi Collected from Sunn Pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), Overwintering Sites in Central Iran

Sunn Pest, Eurygaster integriceps Puton, is the most important pest of wheat and barley in Iran and throughout the Middle East. In this study, different isolates of Beauveria bassiana from overwintering areas in the centre of Iran were collected. In this research, a total of 510 soil samples and cadavers were taken under plants harbouring overwintering Sunn Pest in Semnan, Qum, Kerman and Markazi provinces. The collections were done in late summer and winter 2015 and 2016. The pathogenic fungi were isolated from soil by insect bait method using larvae of wax moth (Galleria mellonella). Data on longitude, latitude, elevation, temperature, soil type and entomopathognic fungi present were recorded for each site. Results indicate that entomopathognic fungi were isolated from 257 of the 510 soil samples, with only Beauveria bassiana and two species Isaria farinosa and Isaria fumosorosea (50.4%). Environmental and geographical impact studies indicated the fungi preferred soil with lower soil temperatures. Significantly more isolates were found at 2300 meters elevation although some were present at 1900 to 2100 meters.

Contact Toxicity and Repellency Evaluation of Rosmarinus eriocalyx Leaves Essential Oil (Lamiaceae) Against Adults Sitophilus granarius (Coleoptera/Beetle) and Anti-Free Radical DPPH Activity

Chemical control using synthetic products against pests of stored foods converted with restrictions such as the toxicity of living things and ecological risks. Today the world opinion is oriented towards a new fight against pests, among the alternative strategy, the use of natural insecticides of plant origin. This work aims to evaluate the insecticide effect of essential oils of Rosmarinus eriocalyx leaves against a wheat pest stored Sitophilus granarius and the evaluation of their antioxidant activity in vitro. The insecticide activity of essential oils of this plant was assessed by the filter paper contact test method and the repulsion test by the method of preference and determination of lethal doses DL50 and DL90, and the percentage of repulsion, measurement of anti-radical activity by trapping free radical DPPH and determining EC50. With regard to the chemical composition of the volatile oils of R. eriocalyx, 1.8-cineol (48.47%), camphor (17.04%), 'pinene' (7.58%), 'pinene' (6.99%) were the main compounds, the results showed that the essential oil of the R.eriocalyx leaves has a very high rate of repulsion PR= 96.25% at the dose of 20 µl/ml after 120 minutes of exposure, the mortality rates of the wheat weevil in the toxicity tests have increased with increased doses and over time. lethal doses for the dose 20 µl/ml has 50% DL50 = 0.306 µl/cm2 and 90% DL90 = 2.513 µl/cm2 for 72 hours of exposure, , in the test system DPPH one determines the trapping activity of radical free of essential oil 23.794% ± 2.908% EC50 = 8.585 ± 2,608 mg/ml. The activity of synthetic antioxidants of gallic acid, quercetin and ascorbic acid were also determined in parallel experiments as positive control. The essential oils of R.eriocalyx leaves can be used as a natural alternative to synthetic insecticides to control pests of stored foodstuffs.

Impact of essential oil from plants on migratory activity of Sitophilus granarius and Tenebrio molitor

Measures against pests should be performed in the context of integrated management of agricultural crops and complex control of pests. Therefore, use of ecologically safe approaches is the best option. Essential oils of plants can make an impact on the main metabolic, biochemical, physiological and behavioural functions of insects. We evaluated the effect of 18 essential oils and 18 dried plants on migratory activity of Sitophilus granarius (Linnaeus, 1758) and Tenebrio molitor Linnaeus, 1758 in conditions of laboratory experiment. Notable repellent activity against S. granarius was exhibited by Citrus sinensis and Picea abies. Repellent action against T. molitor was displayed by dried and cut leaves of Origanum vulgare and Eucalyptus globulus, and also essential oils from Juniperus communis, Р. abies, Pterocarpus santalinus, C. sinensis and C. aurantiifolia. Therefore, out of 18 studied essential oils, only two samples had a notable biological effect on migratory activity of S. granarius and five samples – on T. molitor. These data indicate a possibility of using essential oils or their main components as ecologically safe natural repellents against pests of stored wheat and products of its processing.

Multiple detoxification genes confer imidacloprid resistance to Sitobion avenae Fabricius

The English grain aphid, Sitobion avenae Fabricius, is one of the major wheat pests distributed worldwide. Insecticide application is typically effective for controlling S. avenae, However, S. avenae has developed resistance to multiple insecticides. Thus, it is crucial to elucidate resistance mechanisms in S. avenae. In this study, the mechanisms of resistance to imidacloprid in S. avenae and the risk of cross resistance to other insecticides were investigated. An imidacloprid resistant strain (SA-R) of S. avenae was established via continuous imidacloprid selection with 42.7-fold resistance compared with the susceptible population (SA-S). There was cross resistance in SA-R between imidacloprid and other insecticides tested (acetamiprid, abamectin, chlorpyrifos, and omethoate), with ratios ranging from 10.7- to 24.7-fold higher than SA-S. S, S, S-tributyl phosphorotrithioate (TPP), piperonyl butoxide (PBO), and diethyl maleate (DEM) had synergism with imidacloprid in the SA-R strain with 2.85-, 3.59-, and 2.14-fold reductions, respectively, in LC50 values. Additionally, the activities of cytochrome P450 (P450), glutathione-S-transferases (GST), and carboxylesterase (COE) were significantly higher by 2.69-, 1.42-, and 1.39-fold in the SA-R strain than in the SA-S strain. Based on the S. avenae transcriptome database, 11 P450, two COE, four GST, and two esterase (EST) genes that were significantly induced by imidacloprid were selected to compare gene expression levels between SA-R and SA-S. Fourteen detoxification genes of the 19 tested from the SA-R strain were overexpressed compared to those of the SA-S strain. Silencing of CYP6A14-1, CYP307A1, GST1-1-1, and COE2 by dsRNA feeding resulted in increased susceptibility of SA-R aphids to imidacloprid. These results provide evidence that detoxification genes including CYP6A14-1, CYP307A1, GST1-1-1, and COE2 contribute to resistance to imidacloprid in S. avenae, which was confirmed by RNA interference (RNAi) feeding.

Hardware – wheat pests as elements of the species consortium

Annually in the world, insect pests kill 10–15 % of the crop yield, which in the face of increasing humanity creates a global problem for food security. For the territory of Ukraine in some years, the loss of wheat yields reach 25 % and, in the face of this tendency, real risks to the security of the state are created. Considering that the agrarian trend of the state development has been increasing in recent years, the development of grain-adapted to the ecological and climatic conditions of Ukraine is a priority direction of the development of domestic agriculture. And the development of new environmentally friendly methods of controlling pests of wheat using parasitic organisms will become a fundamentally new and pressing issue in the development of organic production in the country. The general list of pest species that can cause serious wheat yield and forage reduction in Ukraine includes more than 230 names, but only 18 species are able toentail the biggest losses. Among them belong to the order Coleoptera. One insect species is usually a host of several species of mites, nematodes and up to ten species of gregarines and microsporidia. Unfortunately, the taxonomic composition of parasites of phytophagous pets of wheat in Ukraine has not been thoroughly investigated. We studied the interrelation between parasites of 4 phytophagous insects of wheat as well as of 14 insect species found in granaries. The study of the species composition of parasitic organisms of wheat and grain pests is based on the study of the elementary part of the consortium ecosystem, where they act as second order consortia. Phytophagous parasites of wheat and collar pests of cereals, as second-order consorts, have been fragmented worldwide. The purpose of this work is to determine the species composition of gregarine as a component of wheat consortium for their further use in the creation of integrated methods of protection of wheat and products of its processing. As a result, 28 species of gregarines were registered, which belong to seven families (Didymophyidae, Ophryocystidae, Hirmocystidae, Lipotrophidae, Stylocephalidae, Actinocephalidae and Gregarinidae). On the average, 1–2 species of gregarines parasitize in one pest species. 7–10 species of parasites were identified in some insects of the family Tenebrionidae (Tenebrio molitor Linnaeus, 1758 and Tribolium confusum Jacquelin du Val, 1863). Each presented parasite is characteristic of 1–2 species of pests, but there are species of gregarines that infect up to four species of model species, such as Gregarina cuneata Stein, 1848. The largest number of individuals who are infested with gregarines belong to such families as Tenebrionidae and Dermestidae (38,6 % and 36,0 % of the total number of species, respectively). On pests – phytophages parasitizes about 8 species of gregarine families Stylocephalidae, Gregarinidae, Actinocephalidae. For barns pests are recorded barnacles of all 7 families.

Phenotypic and molecular characterization of Hessian fly resistance in diploid wheat, Aegilops tauschii

BackgroundThe Hessian fly (Mayetiola destructor), belonging to the gall midge family (Cecidomyiidae), is a devastating pest of wheat (Triticum aestivum) causing significant yield losses. Despite identification and characterization of numerous Hessian fly-responsive genes and associated biological pathways involved in wheat defense against this dipteran pest, their functional validation has been challenging. This is largely attributed to the large genome, polyploidy, repetitive DNA, and limited genetic resources in hexaploid wheat. The diploid progenitor Aegilops tauschii, D-genome donor of modern-day hexaploid wheat, offers an ideal surrogate eliminating the need to target all three homeologous chromosomes (A, B and D) individually, and thereby making the functional validation of candidate Hessian fly-responsive genes plausible. Furthermore, the well-annotated sequence of Ae. tauschii genome and availability of genetic resources amenable to manipulations makes the functional assays less tedious and time-consuming. However, prior to utilization of this diploid genome for downstream studies, it is imperative to characterize its physical and molecular responses to Hessian fly.ResultsIn this study we screened five Ae. tauschii accessions for their response to the Hessian fly biotypes L and vH13. Two lines were identified that exhibited a homozygous resistance response to feeding by both Hessian fly biotypes. Studies using physical measurements and neutral red staining showed that the resistant Ae. tauschii accessions resembled hexaploid wheat in their phenotypic responses to Hessian fly, that included similarities in larval developmental stages, leaf and plant growth, and cell wall permeability. Furthermore, molecular responses, characterized by gene expression profiling using quantitative real-time PCR, in select resistant Ae. tauschii lines also revealed similarities with resistant hexaploid wheat.ConclusionsPhenotypic and molecular characterization of Ae. tauschii to Hessian fly infestation revealed resistant accessions that shared similarities to hexaploid wheat. Resembling the resistant hexaploid wheat, the Ae. tauschii accessions mount an early defense strategy involving defense proteins including lectins, secondary metabolites and reactive oxygen species (ROS) radicals. Our results reveal the suitability of the diploid progenitor for use as an ideal tool for functional genomics research in deciphering the wheat-Hessian fly molecular interactions.

Sublethal effect of Beauveria bassiana on feeding and fecundity of the sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae)

The sunn pest, Eurygaster integriceps Puton, is a major pest of wheat in West and Central Asia. Studies were conducted to investigate the effect of Beauveria bassiana (teleomorph; Cordyceps bassiana) isolates on the sunn pest. Bioassays were done with adult insects collected from overwintering sites at three different times. The effect of sublethal doses of fungi on the insects’ feeding and fecundity was determined. When the sunn pest adults were treated with 2 × 107 conidia mL−1, all isolates caused significant sunn pest mortality varying between 24 and 100% 12 days after inoculation. There were significant differences between mortality, depending on the date of fungal application. Adult sunn pests treated with B. bassiana at sublethal concentrations caused significantly less damage to wheat leaves than sunn pests in the control. The number of eggs laid by the sunn pest was significantly fewer when wheat plots in plastic greenhouse and field cages were infested with adult sunn pests treated at sublethal concentrations, compared with sunn pests in control plots. Results show that sublethal dosages of B. bassiana reduced sunn pest feeding and fecundity. Applying B. bassiana in sunn pest overwintering sites minimizes the pest populations, which would move to wheat fields in spring.

Infestation and Damage Caused by Wheat Stem Sawflies (Hymenoptera: Cephidae) to Some Wheat Cultivars in Southeast Anatolia Region, Turkey

The European wheat stem sawfly, Cephus pygmeus (Linnaeus, 1767) and the black grain stem sawfly, Trachelus tabidus (Fabricius, 1775) are important and common pests in wheat growing areas of Turkey. These sawfly species continue to be a threat to wheat production in the southeast Anatolia Region of the country. This study was conducted to determine larval infestation rates and yield losses caused by these sawfly species in common wheat cultivars grown in the southeast Anatolia Region. Durum and bread wheat fields were surveyed to record larval infestation and damage caused by these sawfly species in four provinces (Adiyaman, Diyarbakir, Mardin and Sanliurfa) of the region. A total 100 wheat fields were randomly selected and stem samples were taken from each field during the harvest period. Spike length, mean number of grains, grain weight and 1000-grain weight were recorded from 100 infested and healthy spikes and crop losses were calculated for 16 wheat cultivars.The surveyed provinces significantly differed in infestation rates, with the highest infestation level recorded for Diyarbakir province with a mean of 17.4% (range 2.1- 54.3%), while the minimum infestation was determined in Adiyaman province with a mean of 5.3% (range 1.4-17.3%). Durum and bread wheat cultivars had negligible effects on larval infestation. Spike length of infested wheat plants was reduced by 0.9-14.4% and the mean number of grains and grain weight were reduced by 0.5-19.7% and 7.2-28.5%, respectively. The loss in 1000-grain weight was 8.9% in bread wheat cultivars, while the loss was 7.9% in durum wheat cultivars. It was concluded that the loss in 1000-grain weight reached 10.9%. Therefore, appropriate control measures should be taken against stem sawflies in high-infestation locations.

A Review of Rain-Fed Wheat Production Constraints in Zambia

Wheat (Triticum aestivum L.) is an important food crop in Zambia. It is the second most widely grown cereal crop after maize. However, its production and productivity during summer rain season is limited by socio-economic, abiotic and biotic constraints. The socio-economic factors limiting high wheat yield are high cost of inputs, lack of improved rain-fed wheat seed, lack of affordable loans, lack of access to market information and poor mechanization. The abiotic constraints on the other hand include drought, high temperature and aluminium toxicity. Biotic constraints affecting rain-fed wheat production include various weeds, pests (aphids, grass hoppers, pink stalk borers and termites) and diseases (powderly mildew, loose smut, leaf rust, fusarium head blight and spot blotch). Termites being the most serious and destructive pest of rain-fed wheat. Spot blotch is the most devastating and widely distributed among the diseases causing high yield losses of between 7-100% followed by fusarium head blight. This review paper, looks at the factors that limit the production and productivity of rain-fed wheat among small holder farmers in Zambia.

Effects of variable maternal temperature on offspring development and reproduction of Rhopalosiphum padi, a serious global pest of wheat

1. Global warming is occurring at an unprecedented rate. Information about how variable temperature affects insect life‐history traits is still scarce.2. The current study first evaluated the effects of two variable‐temperature treatments [high‐temperature‐variation (HT) treatments and mild‐temperature‐variation (MT) treatments] on the life‐history traits of a maternal generation (F0) of Rhopalosiphum padi, a serious global pest, using a constant normal‐temperature (NT) treatment as a control. Following this, the life‐history traits of the offspring generation (F1) under the NT, MT and HT scenarios were analysed.3. The total developmental duration of the aphid F0 generation was significantly shortened by MT treatments, while it was significantly increased by HT treatments. Adult longevity and the fecundity of F0 were significantly decreased by HT treatments compared with those in the MT and NT treatments, whereas no significant difference was found between the latter two treatments. The HT treatments applied to the F0 generation significantly prolonged the total developmental duration of the F1 generation. The offspring adult longevity was not affected by the mothers' temperature experience. The offspring fecundity was significantly increased when the F0 generation experienced MT treatments. The intrinsic rate of increase (rm) was significantly decreased when the F0 generation experienced an HT scenario. However, the MT scenario experienced by the F0 generation did not significantly affect the rm of their offspring.4. The results will provide new insights into the effects of variable maternal temperature on the individual development and population dynamics of offspring under a global warming scenario.

Climate factors associated with the population dynamics of Sitodiplosis mosellana (Diptera: Cecidomyiidae) in central China

Understanding the impacts of climate on insect pest population dynamics is crucial in forecasting pest outbreaks and developing a sustainable pest management strategy. The orange wheat blossom midge, Sitodiplosis mosellana (Géhin), is a chronic winter wheat (Triticum aestivum L.) pest in China, and its population density can strongly fluctuate. We analyzed climate factors (temperature and precipitation) associated with population dynamics of S. mosellana in a large-scale field trial in central China from 1984 to 2013 using Generalized linear mixed effects models. We found total precipitation during January–March was significantly positively correlated with population density of S. mosellana, whereas temperature parameters were not correlated with the population levels. Moreover, S. mosellana population size was significantly negative effected by interaction between temperature and precipitation, which showed that high precipitation with low temperature in spring also reduced the population density. This suggests that annual population size of S. mosellana in Central China is determined by soil moisture in early spring. These results provide basic information that will help in forecasting population levels and in developing a sound pest management strategy for S. mosellana.

Effects of sucrose supplementation and generation on life‐history traits of Bracon cephi and Bracon lissogaster, parasitoids of the wheat stem sawfly

AbstractKnowledge of the life‐history traits that influence the reproductive success of parasitoids could provide useful information to enhance their effectiveness as biological control agents. The wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) is a major pest of wheat in the Northern Great Plains of North America. The bivoltine, sympatric and specialist parasitoids Bracon cephi (Gahan) and Bracon lissogaster Muesebeck (Hymenoptera: Braconidae) are the only species known to attack C. cinctus in wheat. In the present study, we quantify the body size, longevity, egg load and egg volume of B. cephi and B. lissogaster aiming to test whether these life‐history traits differ among adult females developing from overwintering and summer generation larvae. We also investigate the effect of sucrose supplementation on the same reproductive parameters. The results obtained show no differences between life‐history traits of B. cephi developing from the overwintering and summer generations. By contrast, the egg load of B. lissogaster is significantly different between generations, with overwintered females producing 1.2‐fold more eggs than summer individuals. Sucrose feeding has a strong positive effect on life‐history traits of both parasitoid species and generations. The longevity of sucrose‐fed females of B. cephi is increased three‐fold, whereas the survival of B. lissogaster is increased almost nine‐fold. Females of B. cephi treated with sucrose have four‐fold more mature eggs, whereas the egg load of B. lissogaster is increased 1.15‐ to 1.25‐fold with sugar feeding. Only B. cephi females increase egg volume with sucrose. The present study provides valuable insights on the life‐history and nutritional requirements of these two important parasitoid species.

Spectral characterization of wheat functional trait responses to Hessian fly: Mechanisms for trait-based resistance.

Insect herbivores can manipulate host plants to inhibit defenses. Insects that induce plant galls are excellent examples of these interactions. The Hessian fly (HF, Mayetiola destructor) is a destructive pest of wheat (Triticum spp.) that occurs in nearly all wheat producing globally. Under compatible interactions (i.e., successful HF establishment), HF larvae alter host tissue physiology and morphology for their benefit, manifesting as the development of plant nutritive tissue that feeds the larva and ceases plant cell division and elongation. Under incompatible interactions (i.e., unsuccessful HF establishment), plants respond to larval feeding by killing the larva, permitting normal plant development. We used reflectance spectroscopy to characterize whole-plant functional trait responses during both compatible and incompatible interactions and related these findings with morphological and gene expression observations from earlier studies. Spectral models successfully characterized wheat foliar traits, with mean goodness of fit statistics of 0.84, 0.85, 0.94, and 0.69 and percent root mean square errors of 22, 10, 6, and 20%, respectively, for nitrogen and carbon concentrations, leaf mass per area, and total phenolic content. We found that larvae capable of generating compatible interactions successfully manipulated host plant chemical and morphological composition to create a more hospitable environment. Incompatible interactions resulted in lower host plant nutritional quality, thicker leaves, and higher phenolic levels. Spectral measurements successfully characterized wheat responses to compatible and incompatible interactions, providing an excellent example of the utility of Spectral phenotyping in quantifying responses of specific plant functional traits associated with insect resistance.

Unraveling the Roles of Solitary and Social Web-Making Spiders in Perennial Ecosystems: Influence on Pests and Beneficials

The results show that the orb-weaver spiders, Neoscona theisi and Cyrtophora citricola, occurred in both guava and citrus agroecosystems, and their prey primarily comprised a wide diversity of insect pests. In contrast, the sheet web-constructing social spider, Stegodyphus sarasinorum, occurred only in the citrus agroecosystem and preyed mainly on the beneficial insects, particularly the pollinators, including the Asian honeybee, Apis cerana, along with the predaceous ladybird beetle, Coccinella septempunctata, damselfly, Agriocnemis femina, and the ant, Camponotus compressus. Field observations revealed that the beneficial insects caught and captured by the social spiders comprised mainly the flower-visiting insects of ornamental and weed plants growing in the vicinity of the fruit trees. N. theisi preyed predominantly on pests of paddy (Nephotettix nigropictus, Oxya nitidula), wheat (Rhopalosiphum padi), citrus (Papilio demoleus) and guava (Bactrocera dorsalis) and to a lesser extent on damselflies, houseflies, and ants. C. citricola with smaller orb webs preyed upon N. nigropictus, R. padi, M. domestica, C. septempunctata, and C. compressus. Except the guava pest, B. dorsalis, the pests of paddy and wheat from the infested crops cultivated in the nearby ~ 500-m distant located farm were attracted by the streetlights and were preyed upon by the arboreal spiders. The results highlight the significant role of orb web spiders in the suppression of insect pests of crops and also provide direct evidence of the negative role of social spiders as predators of the Asian honeybee, A. cerana, and other beneficial insects.

Establishment of a wheat banker plant system for the parasitoid Aphidius gifuensis against Myzus persicae in greenhouse chili pepper

The green peach aphid, Myzus persicae Sulzer, is one of the most destructive pests of cruciferous crops with a cosmopolitan distribution. Aphidius gifuensis Ashmead is a solitary parasitoid of M. persicae and Sitobion avenae F., which are important pests of vegetables and winter wheat, respectively. To select a suitable banker plant to culture A. gifuensis in mass as a biological control agent against M. persicae, the reproductive potentials of A. gifuensis with S. avenae and M. persicae as hosts were investigated. The intrinsic rate of increase (r) of A. gifuensis parasitizing S. avenae on wheat cultivar Annong (0.3703 day−1) was significantly greater than those on wheat cultivars Jimai (0.3374 day−1) and Shandong (0.3417 day−1). After a host change, the intrinsic rate of increase (r) of A. gifuensis with M. persicae infesting chili pepper (0.3626 day−1) was significantly greater than on sweet pepper (0.3329 day−1) and tomato (0.3445 day−1). In conclusion, the efficiency at which A. gifuensis in Annong wheat banker plant system controls M. persicae infesting chili pepper might be best among the three tested vegetables.