Pest Of Wheat Research Articles

Potential Bioclimatic Ranges of Crop Pests Zabrus tenebrioides and Harpalus rufipes during Climate Change Conditions

The ground beetles Zabrus tenebrioides and Harpalus rufipes (Coleoptera, Carabidae) are two of the most prevalent pests of wheat and other grasses. This article presents current data on their distribution and the results of modelling the bioclimatic ranges of these species using the maximum entropy method. To improve the model, we used various RStudio packages including the R script “thin points 4-1-18.R” package spThin and the «Raster» RStudio package. We determined the climatic parameters that promote the dispersal of the species, as well as the optimum conditions for the growth of Z. tenebrioides and H. rufipes. Maps forecasting the distribution of the studied species were generated through the perspective of two climate scenarios: RCP 2.6 and RCP 8.5. For the modelling, we utilised 435 geographic points of Z. tenebrioides occurrence and 653 points of H. rufipes occurrence. Both species have similar bioclimatic ranges, and the most favourable conditions for them are fields of grain crops. The most significant parameters influencing Z. tenebrioides are those of moisture, whereas H. rufipes is most sensitive to the temperature parameters. According to the generated climatic models for both species, a decrease in the areas of their ranges would occur in their eastern, more continental areas, with a slight shift towards the north.

Eco-friendly Approach for the Management of Rust Red Flour Beetle, Tribolium castaneum (Herbst) on Wheat Grains

Background: Wheat is the major cereal crop occupying an eminent place in economy of our country. About 10-15% wheat is lost annually due to ravages of stored grains pests during storage. The principal stored grain pest of wheat is red flour beetle Tribolium castaneum (Herbst) which is a cosmopolitan and most serious pest. Methods: The present investigation was carried out in the Entomology Laboratory during 2020-2021, College of Agriculture, Central Agricultural University, Imphal to investigate eco-friendly management of rust red flour beetle, Tribolium castaneum on wheat grains by using different inert materials viz., paddy straw, paddy husk ash, cow dung ash, coal ash, sand dust, saw dust, boric acid and one untreated control with the dose of 1.5 gm/100 gm of wheat grains. Result: The results showed that the boric acid exhibited 100 per cent adult mortality of T. castaneum within 5 days after treatment. Afterwards the next best treatment was cow dung ash, coal ash shows the very effective in treatment in the adult emergence and grain weight loss. Whereas, saw dust shows the least effective treatment in the controlling adult emergence.

Biology of the Cereal Ground Beetle Zabrus tenebrioides Goeze (Coleoptera: Carabidae) in Cereal Fields of Southeastern Anatolia Region, Turkey

The cereal ground beetle,Zabrus tenebrioides Goeze (Coleoptera: Carabidae) is one of the most important pests of wheat in the southeastern region of Turkey. The larval stage lives in the soil and may cause severe damage to wheat crops. Damage by this pest is favored by a wheat monoculture or the use of untreated seeds. High soil moisture and moderate temperatures are favorable conditions for the development and attack of Z. tenebrioides larvae. The southeastern Anatolia region of Turkey is a hub of cereal production and Z. tenebrioides can attack the seedling stage of cereals in this region, resulting in heavy economic losses. This study was carried out during the years 2015 and 2017 to determine the biology of Z. tenebrioides in the southeastern Anatolia region. Surveys could not be carried out in 2016 as the climatic conditions were not suitable. Adults of this pest were monitored and data on the biology, aestivation and hibernation periods of Z. tenebrioides were recorded. Results indicated that aestivation (the last week of October) and hibernation (at the end of November and most of December) times, and the duration of egg, larval, pupal and adult stages are closely associated with soil temperature and moisture, followed by temperature and humidity of food and air. It was further observed that pest populations increased when the temperature was low and humidity was high, especially in the years receiving high precipitation during early spring and late autumn.

Comparative Hessian Fly Larval Transcriptomics Provides Novel Insight into Host and Nonhost Resistance

The Hessian fly is a destructive pest of wheat. Employing additional molecular strategies can complement wheat’s native insect resistance. However, this requires functional characterization of Hessian-fly-responsive genes, which is challenging because of wheat genome complexity. The diploid Brachypodium distachyon (Bd) exhibits nonhost resistance to Hessian fly and displays phenotypic/molecular responses intermediate between resistant and susceptible host wheat, offering a surrogate genome for gene characterization. Here, we compared the transcriptomes of Biotype L larvae residing on resistant/susceptible wheat, and nonhost Bd plants. Larvae from susceptible wheat and nonhost Bd plants revealed similar molecular responses that were distinct from avirulent larval responses on resistant wheat. Secreted salivary gland proteins were strongly up-regulated in all larvae. Genes from various biological pathways and molecular processes were up-regulated in larvae from both susceptible wheat and nonhost Bd plants. However, Bd larval expression levels were intermediate between larvae from susceptible and resistant wheat. Most genes were down-regulated or unchanged in avirulent larvae, correlating with their inability to establish feeding sites and dying within 4–5 days after egg-hatch. Decreased gene expression in Bd larvae, compared to ones on susceptible wheat, potentially led to developmentally delayed 2nd-instars, followed by eventually succumbing to nonhost resistance defense mechanisms.

Ecological requirements drive the variable responses of wheat pests and natural enemies to the landscape context

Abstract Semi‐natural habitats (SNH) are considered essential for pest‐suppressive landscapes, but their influence on crop pests and natural enemies can be highly variable. Instead of SNH per se, the availability of resources, such as pollen and nectar, may be more relevant for supporting pest control. Here, we assessed the spatiotemporal variation of multiple insect pests (cereal leaf beetles and aphids) and natural enemies (predators and aphid parasitoids) in wheat fields and their responses to landscape context and flower availability. We combined detailed information on pollen use by natural enemies with the specific distribution of pollen‐providing plants across a gradient of landscape composition and configuration. The abundance of wheat pests was tightly linked to wheat development stage. Syrphids colonised the fields early in the season, while the abundance of other enemies increased later in the season. The responses of pests to landscape structure were variable and, while some pests had low abundances in landscapes with high edge density and SNH cover, Sitobion avenae abundance was positively associated with SNH cover. Lacewings, syrphids and cereal leaf beetles were abundant in landscapes with diverse and abundant flower resources, whereas the abundance of parasitoids and Nabis sp. was driven by aphid abundance. We detected no significant indirect effects of landscape on pests via natural enemies. Synthesis and applications. Our findings highlight the need for conservation biological control to go beyond ‘one size fits all’ and consider the specific ecology of the involved organisms, even for a single crop type. Landscapes with high edge density and flowering woody plants may support natural enemies, in particular syrphids, which colonised the fields early in the season. Incentives for pest‐suppressive landscapes should focus on tailored strategies that disfavour dominant cereal pests and simultaneously enhance natural enemies according to their ecological requirements.

Impact of agricultural and tillage systems on the main pests of winter wheat

Impact of agricultural and tillage systems on the main pests of winter wheat

A Genomic Survey of Mayetiola destructor Mobilome Provides New Insights into the Evolutionary History of Transposable Elements in the Cecidomyiid Midges.

The availability of the Whole-Genome Sequence of the wheat pest Mayetiola destructor offers the opportunity to investigate the Transposable Elements (TEs) content and their relationship with the genes involved in the insect virulence. In this study, de novo annotation carried out using REPET pipeline showed that TEs occupy approximately 16% of the genome and are represented by 1038 lineages. Class II elements were the most frequent and most TEs were inactive due to the deletions they have accumulated. The analyses of TEs ages revealed a first burst at 20% of divergence from present that mobilized many TE families including mostly Tc1/mariner and Gypsy superfamilies and a second burst at 2% of divergence, which involved mainly the class II elements suggesting new TEs invasions. Additionally, 86 TEs insertions involving recently transposed elements were identified. Among them, several MITEs and Gypsy retrotransposons were inserted in the vicinity of SSGP and chemosensory genes. The findings represent a valuable resource for more in-depth investigation of the TE impact onto M. destructor genome and their possible influence on the expression of the virulence and chemosensory genes and consequently the behavior of this pest towards its host plants.

Attraction of Sitophilus zeamais (Coleoptera: Curculionidae) to Four Host Plants

The maize weevil Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) is an important pest of stored grains, predominantly maize (Zea mays L.), wheat (Triticum L. spp.), rice (Oryza L. spp.), and sorghum (Sorghum bicolor [L.] Moench) (all Poaceae). Weevil infestations occur in the field and weevils are carried to the storage facility after harvest. Infestation also occurs in the grain storage facility. There is no effective field or storage trapping system for control. They are commonly parasitized by Pteromalidae Dalman (Hymenoptera: Chalcidoidea) spp. parasitoids in the Tropics; however, there is no biocontrol use of these Hymenoptera. Therefore, pesticide application and the development of resistant grain are the current control strategies; although, studies have indicated that odors associated with the grain upon which the weevils feed, mate, and oviposit are attractive to the weevil. Host plant produced volatiles and their associations with the maize weevil have not been investigated fully. To better understand the weevil's attraction to crop plants, a study was initiated to investigate the weevil's preference for immature host plants. Weevils that had been reared on 4 types of grain for several generations were presented immature plants of all 4 types of grains in choice tests to determine if they prefer grains of the host plant on which they had been reared. This research demonstrated that immature rice plants have the greatest attraction, and that previous feeding did not influence the weevil's host plant attraction. The isolation of key rice plant semiochemicals will be the focus in the development of an attractant for S. zeamais and may also prove effective for the control of Sitophilus oryzae (L.) (Coleoptera: Curculionidae).

Microbial Volatile Organic Compounds from Tempered and Incubated Grain Mediate Attraction by a Primary but Not Secondary Stored Product Insect Pest in Wheat

There has been a dearth of research elucidating the behavioral effect of microbially-produced volatile organic compounds on insects in postharvest agriculture. Demonstrating attraction to MVOC’s by stored product insects would provide an additional source of unique behaviorally-relevant stimuli to protect postharvest commodities at food facilities. Here, we assessed the behavioral response of a primary (Rhyzopertha dominica) and secondary (Tribolium castaneum) grain pest to bouquets of volatiles produced by whole wheat that were untempered, or tempered to 12%, 15%, or 19% grain moisture and incubated for 9, 18, or 27 days. We hypothesized that MVOC’s may be more important for the secondary feeder because they signal that otherwise unusable, intact grains have become susceptible by weakening of the bran. However, contrary to our expectations, we found that the primary feeder, R. dominica, but not T. castaneum was attracted to MVOC’s in a wind tunnel experiment, and in a release-recapture assay using commercial traps baited with grain treatments. Increasing grain moisture resulted in elevated grain damage detected by near-infrared spectroscopy and resulted in small but significant differences in the blend of volatiles emitted by treatments detected by gas chromatography coupled with mass spectrometry (GC–MS). In sequencing the microbial community on the grain, we found a diversity of fungi, suggesting that an assemblage was responsible for emissions. We conclude that R. dominica is attracted to a broader suite of MVOC’s than T. castaneum, and that our work highlights the importance of understanding insect-microbe interactions in the postharvest agricultural supply chain.

Precise mapping of QTL for Hessian fly resistance in the hard winter wheat cultivar 'Overland'.

A major QTL for Hessian fly resistance was precisely mapped to a 2.32 Mb region on chromosome 3B of the US hard winter wheat cultivar 'Overland'. The Hessian fly (HF, Mayetiola destructor) is a destructive insect pest of wheat in the USA and worldwide. Deploying HF-resistant cultivars is the most effective and economical approach to control this insect pest. A population of 186 recombinant inbred lines (RILs) was developed from 'Overland' × 'Overley' and phenotyped for responses to HF attack using the HF biotype 'Great Plains'. A high-density genetic linkage map was constructed using 1,576 single nucleotide polymorphism (SNP)markers generated by genotyping-by-sequencing(GBS). Two quantitative trait loci (QTLs) with a significant epistatic effect on HF resistance were mapped to chromosomes 3B (QHf.hwwg-3B) and 7A (QHf.hwwg-7A) in Overland, which are located in similar chromosome regions as found for H35 and H36 in the cultivar 'SD06165', respectively. QHf.hwwg-3B showed a much larger effect on HF resistance than QHf.hwwg-7A. Five and four GBS-SNPs, respectively, in the QHf.hwwg-3B and QHf.hwwg-7A QTL intervals were converted into Kompetitive allele specific polymerase chain reaction (KASP) markers. QHf.hwwg-3B was precisely mapped to a 2.32Mb interval (2,479,314-4,799,538bp) using near-isogenic lines (NILs) and RILs that have recombination within the QTL interval. The US winter wheat accessions carrying contrasting alleles at KASP markers KASP-3B4525164, KASP-7A47772047 and KASP-7A65090410 showed significant difference in HF resistance. The combination of the two KASP markers KASP-3B3797431 and KASP-3B4525164 is near-diagnostic for the detection ofQHf.hwwg-3B in a US winter wheat panel and can be potentially used for screening the QTL in breeding programs.

Identification of a major QTL for Hessian fly resistance in wheat cultivar ‘Chokwang’

The Hessian fly (HF, Mayetiola destructor) is one of the destructive pests of wheat (Triticum aestivum L.) worldwide. Resistant cultivars can effectively minimize wheat damage due to this insect pest. To identify new quantitative trait loci (QTL) for HF resistance, a population of recombinant inbred lines (RILs) was developed from a cross between the HF-resistant wheat cultivar ‘Chokwang’ and susceptible wheat ‘Ning 7840’, and phenotyped for responses to HF attack. A linkage map was constructed using 1147 single nucleotide polymorphism (SNP) markers generated from genotyping-by-sequencing (GBS). One major QTL, QHf.hwwg-6BS, for HF-resistance was identified on chromosome arm 6BS, which explained up to 84.0% of the phenotypic variation and was contributed by Chokwang. Two RILs showed recombination in the candidate interval of QHf.hwwg-6BS, which delimited QHf.hwwg-6BS to a 4.75 Mb physical interval between 6,028,601 bp and 10,779,424 bp on chromosome arm 6BS of IWGSC Chinese Spring reference genome RefSeq v2.0. Seven GBS-SNPs in the candidate interval were converted into Kompetitive allele specific polymerase chain reaction (KASP) markers. Two of them, KASP-6B112698 and KASP-6B7901215, were validated in a U.S. winter wheat panel. KASP-6B112698 was nearly diagnostic, thus can be used to screen QHf.hwwg-6BS and pyramid it with other resistance genes in breeding programs.

First report of Liogenys suturalis (Blanchard) (Coleoptera: Scarabaeidae: Melolonthinae) in Argentinian crops and the first report of damage on soybean

AbstractLiogenys Guérin‐Méneville is one of the most species rich genera in the Scarabaeidae family endemic to South America. Some species of this genus are important root‐feeding pests of maize, soybean, wheat and oat in their larval stage. Prior to the present study, all known reports of damage caused by any Liogenys species were from Brazil. Since 2006 in Argentina white grubs of the genus Liogenys (not previsouly identified to species level) have been recorded causing a decrease in soybean yields. This research confirms that the Argentinian species is L. suturalis (Blanchard), an important pest already recorded in Brazil but associated with yield losses of maize crops instead of soybean. Taxonomical and biological data observed in Argentinian populations are presented. This is the first record of L. suturalis damaging soybean and its first report in Argentinian crops.

Development of a pest threshold decision support system for minimising damage to winter wheat from wheat bulb fly, Delia coarctata

AbstractWheat bulb fly, Delia coarctata, is an important pest of winter wheat in the UK, causing significant damage of up to 4 t/ha. Accepted population thresholds for D. coarctata are 250 eggs/m2 for crops sown up to the end of October and 100 eggs/m2 for crops sown from November. Fields with populations of D. coarctata that exceed the thresholds are at higher risk of experiencing economically damaging infestations. In the UK, recent withdrawal of insecticides means that only a seed treatment (Signal 300 ES) is available for chemical control of D. coarctata; however, this is only effective for late‐sown crops and accurate estimations of annual population levels are required to ensure a seed treatment is applied if needed. As a result of the lack of postdrilling control strategies, the management of D. coarctata is becoming reliant on nonchemical methods of control. Control strategies that are effective in managing similar stem‐boring pests of wheat include sowing earlier and using higher seed rates to produce crops with greater pest tolerance. In this study, we develop two predictive models that can be used for integrated D. coarctata management. The first is an updated pest level prediction model that predicts D. coarctata populations from meteorological parameters with a predictive accuracy of 70%, a significant improvement on previous prediction models. Our second model predicts the maximum number of shoots for a winter wheat crop that would be expected at the terminal spikelet development stage. This shoot number model uses information about the thermal time from plant emergence to terminal spikelet, leaf phyllochron length, plant population and sowing date to predict the degree of tolerance a crop will have against D. coarctata. The shoot number model was calibrated against data collected from five field experiments and tested against data from four experiments. Model testing demonstrated that the shoot number model has a predictive accuracy of 65.7%. The foundation for a future decision support system using these models for the sustainable management of D. coarcata risk is described. It should be noted that these models represent a stepping‐stone towards a decision support system and that further model validation over a wider geographic range is required.

THE IMPORTANCE OF USEFUL ARTHROPOD FAUNA IN LIMITING WHEAT PESTS IN THE CENTER OF TRANSYLVANIA

The important role of entomophagous present in the trophic network of biocenoses, is widely debated in numerous papers. Throughout the vegetation period, field crops are invaded by a host of entomophagous, their role being important in limiting pests. Due to the importance of useful arthropod fauna for limiting wheat pests, during 2016-2017, its monitoring was carried out on the winter wheat culture, in two locations: at Turda, open field and in Bolduţ, field with agroforestry curtains, from ARDS Turda. The entomophagous collection was performed decadally with entomological net, a hundred double threads for each sample, in two variants: untreated with insecticides, and treated with insecticides. The data obtained indicates the fact that in the field with agroforestry curtains, the abundance of entomophagous it was higher, and in the variant where vegetation treatments with insecticides have been applied, the number of entomophagous was lower, compared to the untreated variant.

Examining the genetic diversity of the orange blossom wheat midge, Sitodiplosis mosellana (Géhin), across North America

AbstractThe orange blossom wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), is a significant pest of wheat (Triticum spp.) grown in the Northern Hemisphere. It was accidently introduced to North America over 200 years ago and has subsequently spread throughout the northern Great Plains. Since 2010, several Canadian spring wheat varieties containing the resistance gene Sm1 have been released. Due to the potential of wheat midge populations to evolve virulent biotypes to Sm1, cultivars containing Sm1 are grown with a susceptible cultivar in an interspersed refuge. An understanding of the genetic diversity of wheat midge populations could provide important information on the potential development of resistance to Sm1. In the current study, we used two mitochondrial genes (CO1 and ND4) from wheat midge collected across the northern Great Plains and Québec in North America to assess population structure and genetic diversity. We found limited genetic diversity and population structure across the sampled North American populations. We also assessed North American haplotype similarity to wheat midge collected from Europe and China and found high similarity between North American and European populations, although sampling in Europe was limited. This supports the hypothesis that North American populations originated from Europe.

Effects of Crop Rotation on Spring Wheat Yield and Pest Occurrence in Different Tillage Systems: A Multi-Year Experiment in Finnish Growing Conditions

Crop rotation and soil tillage are among key factors impacting cropping system productivity, pest management and soil health. To assess their role in northern cropping systems, we quantified the effects of crop rotation on spring wheat yield in different tillage systems based on a long-term (2005–2017) field experiment in southwestern Finland. In addition, effects of crop rotation on weeds, plant pathogens, and pest insects were assessed. Three types of crop rotation were compared: monoculture (spring wheat), 2-year rotation (spring wheat—turnip rape—spring wheat—barley) and 4-year rotation (spring wheat—turnip rape—barley—pea) under no-tillage and plowing. A diversified crop rotation improved spring wheat yield by up to 30% in no-tillage and by 13% under plowing compared with monoculture. Overall, the yield quantity and quality differences between crop rotations were higher in no-tillage plots than in plowed plots. The occurrence of weed species in spring wheat before herbicide control was highest in the four-year crop rotation and lowest in the wheat monoculture. For plant diseases, wheat leaf blotch disease severity, mainly caused by Pyrenophora tritici-repentis, was lowest in the most diverse crop rotation. On average, wheat leaf blotch disease severity was 20% less when wheat was grown every fourth year compared with wheat monoculture. The effect of crop rotation on stem and root diseases became apparent after 6 years of rotation and the disease index was lowest in the most diverse crop rotation. Neither rotation nor tillage affected the control need of wheat midge (Sitodiplosis mosellana). Based on our results, diverse crop rotations including cereals, oilseed crops, and legumes increase yield and reduce plant disease severity of spring wheat in Finland, with the magnitude being larger in no-tillage systems.

Tillage Intensity Influences Insect-Pest and Predator Dynamics of Wheat Crop Grown under Different Conservation Agriculture Practices in Rice-Wheat Cropping System of Indo-Gangetic Plain

Tillage can alter the soil habitats wherein many insect pests and their natural enemies reside during at least part of their life cycle. To enhance crop productivity and reduce climate change effects, conservation agriculture (CA) with reduced-tillage or no-tillage practices have been advocated to farmers. However, information relating to the effect of CA on insect pests and their natural enemies is very scarce, at least in the Indo-Gangetic region. In this study, the effect of tillage on the abundance of, and damage by, major insect pests (foliar aphids, root aphids, termites, and pink stem borer) and their natural enemies in wheat managed under three tillage practices, i.e., zero-till (ZT), reduced tillage (RT), and conventional tillage (CT) with (protected) and without (unprotected) insecticide protection scenarios, was investigated. Foliar aphid and termite numbers were lowest in the ZT-protected system, and highest in the CT-unprotected system. Pink stem borer damage was significantly higher in the ZT-unprotected system, whereas the root aphid number was maximum in the RT-unprotected system. The natural enemies of these four major insect pests of wheat showed variable trends under the studied tillage systems. The abundance and damage of these major insect pests showed a positive correlation with the normalized difference vegetative index (NDVI) and canopy temperature. The dynamics of the insect pests and their predators were driven by soil habitat-related changes (direct) as well as crop growth-related effects (indirect). A fine-tuning of insect-pest management tactics based on these relations would enhance the success of CA systems.

First combined resistance to Hessian fly and Sunn pest identified in synthetic hexaploid wheat

AbstractHessian fly, Mayetiola destructor (Say), and Sunn pest, Eurygaster integriceps (Puton), are the two most damaging insect pests of wheat in North Africa, West and Central Asia. Host plant resistance is the most environmental friendly, cost‐effective and practical means of controlling insect pests. Twenty synthetic hexaploid wheat lines selected as resistant to Syrian Sunn pest in 2010 were screened for resistance to Moroccan Hessian fly biotype in 2016. The Hessian fly screening was carried out in standard greenhouse flats using a randomized complete block design with three replications, with susceptible and resistant checks in every test flat. The results showed that three synthetic hexaploid wheat lines exhibited resistance to both Moroccan Hessian fly biotype and Syrian Sunn pest. This is the first record of combined resistance to these two pests in wheat. Mapping populations using these sources of resistance are being developed using double haploid techniques for subsequent genetic characterization and identification of linked molecular markers for marker assisted selection.

Initiation of compatible wheat-Hessian fly interactions triggers the expression of a novel UDP-glycosyltransferase, MdesUGT1, in virulent Hessian fly larvae

Insect UDP-glycosyltransferases (UGTs) play an important role in detoxification of substrates such as plant allelochemicals, and cuticle formation by the process of glucosidation. Hessian fly (Mayetiola destructor), belonging to the order Diptera (Family: Cecidomyiidae), is a destructive pest of host wheat causing significant economic losses. In the current study, using the assembled genome, we identified thirteen genes in M. destructor that belong to the family of UGTs (MdesUGT). Expression profiling revealed differential expression of MdesUGT genes in Hessian fly feeding instars. Further, we report the molecular cloning of MdesUGT1, designated as UGT301F1, from M. destructor. Characterization of the MdesUGT1 amino acid sequence revealed a conserved signature motif and sugar donor-binding domains characteristic of UGT proteins. Further expression analysis revealed dramatic increase in transcript accumulation of MdesUGT1 in the first and second feeding instars during compatible interactions (susceptible wheat, virulent larvae) but lacked significant upregulation during incompatible wheat Hessian fly interactions. Similar increase in MdesUGT1 transcripts was also observed during interactions of Hessian fly with nonhost, Brachypodium distachyon. These findings suggest the possible early involvement of MdesUGT1 in detoxification of plant toxins, and subsequent role in cuticular formation, thus contributing to the growth and development of this dipteran insect pest. Identification and characterization of insect UGTs could provide valuable insights into the detoxification and growth inhibitory mechanisms and facilitate future plant pest management strategies.

Diversity, rate, and distribution of wheat midge parasitism in the Peace River region of Alberta, Canada

AbstractWheat midge,Sitodiplosis mosellana(Géhin) (Diptera: Cecidomyiidae), is a major pest of wheat (Poaceae) that was first reported in the Peace River region of northwestern Alberta, Canada in 2011. Although parasitism is an important factor of mortality in wheat midge elsewhere, little is known about the prevalence, species, or distribution of wheat midge parasitoids in the Peace River region. To address this knowledge gap, we conducted a survey of wheat midge parasitoids in commercial wheat fields across the region in 2016 and 2017. For a given field, parasitism of wheat midge larvae ranged from 36 to 71%. All but one parasitoid (n= 2167) were identified asMacroglenes penetrans(Kirby) (Hymenoptera: Pteromalidae). The exception was a specimen in the genusInostemmatentatively identified asI. walkeriKieffer (Hymenoptera: Platygasteridae). These findings identify parasitism as an important factor that is suppressing populations of wheat midge in the Peace River region, provide the first report ofInostemma walkerifor North America, and provide the first report of this species as a parasitoid ofS. mosellana.