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Concept: Cecidomyiidae

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Numerous species of gall midges (Diptera: Cecidomyiidae) have been recorded from saltbush (Chenopodiaceae: Atriplex) around the world but only 11 of them belong to the large cecidomyiid genus Asphondylia. Of these, two species were described in the late 19th century from complex bud galls on Atriplex halimus in the Mediterranean Basin. In the present study Asphondylia punica is redescribed, A. conglomerata is synonymized with it, and Asphondylia scopuli is described from Atriplex lanfrancoi, an endemic plant to the Maltese Islands. Descriptions are accompanied by information about the galls and life history of the gall midges, and a review of the parasitic Hymenoptera associated with A. scopuli is provided. Four species of parasitoids were found and attributed to the families Eurytomidae, Pteromalidae, Eupelmidae and Eulophidae, of which the pteromalid Mesopolobus melitensis is described as new.

Concepts: Nematocera, Species, Flies, Parasitoid, Apocrita, Biological pest control agents, Cecidomyiidae, Atriplex

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Gall-forming arthropods are highly specialized herbivores that, in combination with their hosts, produce extended phenotypes with unique morphologies [1]. Many are economically important, and others have improved our understanding of ecology and adaptive radiation [2]. However, the mechanisms that these arthropods use to induce plant galls are poorly understood. We sequenced the genome of the Hessian fly (Mayetiola destructor; Diptera: Cecidomyiidae), a plant parasitic gall midge and a pest of wheat (Triticum spp.), with the aim of identifying genic modifications that contribute to its plant-parasitic lifestyle. Among several adaptive modifications, we discovered an expansive reservoir of potential effector proteins. Nearly 5% of the 20,163 predicted gene models matched putative effector gene transcripts present in the M. destructor larval salivary gland. Another 466 putative effectors were discovered among the genes that have no sequence similarities in other organisms. The largest known arthropod gene family (family SSGP-71) was also discovered within the effector reservoir. SSGP-71 proteins lack sequence homologies to other proteins, but their structures resemble both ubiquitin E3 ligases in plants and E3-ligase-mimicking effectors in plant pathogenic bacteria. SSGP-71 proteins and wheat Skp proteins interact in vivo. Mutations in different SSGP-71 genes avoid the effector-triggered immunity that is directed by the wheat resistance genes H6 and H9. Results point to effectors as the agents responsible for arthropod-induced plant gall formation.

Concepts: Gene, Bacteria, Evolution, Organism, Oak, Hessian fly, Cecidomyiinae, Cecidomyiidae

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Mayetiola destructor (Say) (Diptera: Cecidomyiidae) is a destructive pest of wheat and is mainly controlled by deploying resistant cultivars. Unfortunately, wheat resistance to Hessian fly is often lost when temperatures rise to a certain level. This study analyzed temperature sensitivity of 20 wheat cultivars that contain different resistance ® genes. The lowest temperatures at which the percentage of resistant plants fell below 50% in an assay were 18°C for ‘D6647 H17’ (921680D1-7) (containing the R gene H17), 20°C for ‘Redland’ (H18), 22°C for ‘84702B14-1-3-4-3’ (H19), 24°C for ‘Carol’ (H3) and ‘Sincape90’ (H29), 26°C for ‘Erin’ (H5), ‘Jori 13’ (H20), and ‘PI59190’ (H28), 28°C for ‘Joy’ (H10), ‘KS99WGRC42’ (Hdic), ‘Karen’ (H11), ‘Caldwell’ (H6), and ‘Seneca’ (H7H8), 30°C for ‘KS85WGRC01’ (H22) and ‘KS92WGRC20’ (H25), 32°C for ‘Molly’ (H13), and 34°C for ‘Iris’ (H9). The three cultivars ‘H32 Synthetic’ (H32), ‘81602C5-3-3-8-1’ (H15), and ‘KS93WGRC26’ (H26) exhibited the most resistance to temperature increases. The percentages of resistant plants remained above 50% at 36°C for these three cultivars, the highest temperature that can be tested without significantly damaging wheat plant growth. The temperature sensitivity of R gene-mediated fly resistance is also strongly affected by genetic background of wheat cultivars that contain a specific R gene. Our data should provide useful information for breeding wheat resistance to control Hessian fly damage in different regions based on historic temperature data.

Concepts: Nematocera, Pest insects, Hessian fly, Cecidomyiinae, Cecidomyiidae, Mayetiola, Lasiopteridi, British H class submarine

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Monitoring of Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae), populations is important for targeted management methods. Also, effectiveness of monitoring efforts is critical to surveillance efforts in regions of the world without this pest. Current Hessian fly monitoring traps rely purely on a single attractant, the female sex pheromone, which is ineffective for monitoring females in the population. Our objective was to examine another attractant targeting vision of both males and females. To do this, we evaluated emitted light of various wavelengths and intensities produced by light-emitting diodes (LEDs). Hessian flies were released in the center of a four-leaf clover-shaped arena, which contained an LED within each collection cup at the apex of each of the four cloverleaves. Initially, we examined a range of colors, including red, amber, green, and blue, with wavelengths of 624, 590, 527, and 472 nm, respectively. Both sexes of Hessian fly preferred green LEDs; therefore, we examined specific wavelengths within the green spectrum (502, 525, and 565 nm), and varied light intensities (4, 8, 12, and 16 W/m2). Specifically, females preferred wavelengths in the lower region of the green spectrum (502 and 525 nm), and both sexes preferred high intensity light (16 W/m2). This is the first report of Hessian fly attraction to select emitted wavelengths and intensities from LEDs under controlled conditions. Leveraging these results into new trap designs will add a second sensory modality to the existing trap; however, future studies are needed to assess attraction to LED traps under field conditions.

Concepts: Male, Female, Sex, Light-emitting diode, 175, Hessian fly, Cecidomyiinae, Cecidomyiidae

0

Gall midges (Diptera: Cecidomyiidae) damage mango by feeding on flowers and fruit tissues, inducing galls on leaves, and providing inoculums of anthracnose. Dasineura amaramanjarae Grover and Procontarinia mangiferae (Felt), two gall midges that damage flowers in all mango-growing areas of the world, have recently been recorded in Pakistan, and studies were conducted in 2011 and 2012 on the within-tree and orchard distribution patterns and cultivar preference of both species in Pakistan at one location (Rahim Yar Khan). Both gall midge species were found on all mango cultivars examined (Chaunsa, Fajri, Dusehri, Surkha, Sindhri, and Anwar Ratul), with the most damage occurring to Surkha and Dusehri. Research on midge distribution patterns in different parts of mango orchards (central, southern, northern, eastern, and western sides) showed these species to be found in all areas, with the greatest numbers in the central and southern regions. In addition, both species were most abundant on the lower parts of the mango tree canopy.

Concepts: Nematocera, Flies, Mango, Oak, Orchard, Cecidomyiidae, Rahim Yar Khan District, Alphonso

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Mayetiola destructor (Say) is a serious pest of wheat, Triticum aestivum L., in North America, North Africa, and Central Asia. Singly deployed resistance genes in wheat cultivars have provided effective management of Hessian fly populations for >50 yr. Thirty-five H genes have been documented. Defense mediated by the H gene constitutes strong selection on the Hessian fly population, killing 100% of larvae. A mutation in a matching Hessian fly avirulence gene confers virulence to the H gene, leading to survival on the resistant plant. As the frequency of virulence rises in the population, the H gene loses its effectiveness for pest management. Knowing the frequency of virulence in the population is not only important for monitoring but also for decisions about which H gene should be deployed in regional wheat breeding programs. Here, we present a novel assay for detecting virulence in the field. Hessian fly males were collected in Alabama, Georgia, North Carolina, and South Carolina using sticky traps baited with Hessian fly sex pheromone. Utilizing two PCR reactions, diagnostic molecular markers for the six alleles controlling avirulence and virulence to H13 can be scored based on band size. Throughout the southeast, all three avirulence and three virulence alleles can be identified. In South Carolina, the PCR assay was sensitive enough to detect the spread of virulence into two counties previously documented as 100% susceptible to H13. The new assay also indicates that the previous methods overestimated virulence in the field owing to scoring of the plant instead of the insect.

Concepts: Insect, United States, Wheat, South Carolina, Hessian fly, Cecidomyiinae, Cecidomyiidae, Mayetiola

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The Hessian fly, Mayetiola destructor Say, is an important pest of winter wheat in the Southern Great Plains of the United States. As larvae feed behind the leaf sheath, infestations often go undetected until crop damage is evident, and there are no remedial actions that can prevent economic loss once a field is infested. The recent discovery of the sex-attractant pheromone of the Hessian fly provides an opportunity to use pheromone traps to detect and monitor adult activity and potentially better manage this pest. Adult male Hessian fly activity was monitored during 4 yr at six locations from northcentral Oklahoma, 36° N latitude, south to central Texas, 31° N latitude. In Oklahoma, trap captures were low in the fall, no flies were captured during the winter, and the largest number of flies was captured in the spring. However, in southcentral Texas, adults were captured throughout the fall, winter, and in the spring when trap captures were again the greatest. The relationship between trap captures and density of Hessian fly larvae per tiller was investigated during the fall and spring. Although large numbers of adults (>100 per trap per day) were often captured, economic infestation of larvae rarely developed. Results identify optimum times for field sampling to determine immature Hessian fly infestations in wheat in Oklahoma and Texas.

Concepts: Insect, United States, Texas, Fly, Great Plains, Hessian fly, Cecidomyiinae, Cecidomyiidae

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Since 2005, mango has been damaged by a group of new pests, the gall midges, in all mango-growing areas of Pakistan. Little is known about these pests in Pakistan. In this report, we present information on the occurrence, damage patterns, methods for monitoring, and management of Procontarinia mangiferae (Felt), a mango gall midge found in the country. At the study site (Rahim Yar Khan, a district of the province Punjab, Pakistan), the pest was active from January/February to April as eggs, larvae, and adults on mango inflorescence buds, branches (axillaries), and immature fruits. Females of P. mangiferae oviposited in inflorescence tissues, and larvae, after feeding on plant tissues, dropped to the soil under the mango trees for pupation from February to April. Mango trees in commercial orchards were more heavily damaged by P. mangiferae than were isolated trees in farmer fields (66.7%). The adults of P. mangiferae were captured on sticky traps of all tested colors, and were in flight from January to May. Captures per trap were highest on yellow traps, followed by green, blue, and clear traps. Control of mango gall midge was effectively provided by the synthetic insecticide bifenthrin (Talstar 10 EC) and also by application of neem seed kernel extract on the tree canopy if integrated with raking the soil under the mango tree canopy.

Concepts: Nematocera, Tree, Flies, Mango, Orchard, Cecidomyiidae, Rahim Yar Khan District

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Three new Nearctic genera of gall midges (Diptera: Cecidomyiidae), each with a new species, are described: Helianthecis Gagné for Helianthecis capitum Gagné, new species, that lives in flower heads of Helianthus spp. (Asteraceae) from North Dakota to Texas; Lonicerae Gagné for Lonicerae russoi Gagné, new species, and Lonicerae lonicera (Felt), new combination, that form bud galls on Lonicera spp. (Caprifoliaceae) in California; and Chiosperma Gagné for Chiosperma turgidum Gagné, new species, that forms a bud gall on Symphoricarpos albus (L.) S.F. Blake (Caprifoliaceae) in Washington. The three new genera belong to the supertribe Lasiopteridi and are placed in the tribe Oligotrophini. The tribes Oligotrophini and Rhopalomyiini are combined.

Concepts: Nematocera, Flower, Flies, Oak, Hessian fly, Cecidomyiinae, Cecidomyiidae, Symphoricarpos

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Since 2010, there has been a resurgence of the saddle gall midge, Haplodiplosis marginata (von Roser), in Belgium and several other European countries, with this pest sometimes causing severe damage in cereals. In 2012 and 2013, field trials were conducted in heavily infested fields to assess its impact on winter wheat crops and to determine efficient ways of dealing with severe infestations.

Concepts: Nematocera, Wheat, Europe, Field, Flies, Crops, 2010s, Cecidomyiidae