Native and invasive stink bugs (Hemiptera: Pentatomidae) and the closely related invasive Megacopta cribraria (Hemiptera: Plataspidae) are agricultural pests in the southeastern United States. Natural enemies, from various phyla, parasitize these pests and contribute to population regulation. We specifically investigated Nematoda infections in pentatomid and plataspid pests in one soybean field in South Carolina in 2015. Nematodes were identified through molecular and morphological methods and assigned to family Mermithidae, genus Agamermis. This study reports mermithid nematode infection in immature M. cribraria for the first time and provides the first mermithid host record for the stink bugs Chinavia hilaris, Euschistus servus, and another Euschistus species, and a grasshopper (Orthoptera: Acrididae) in South Carolina. The same Agamermis species infected all hosts. The broad host range and prevalence suggests that Agamermis may be an important contributor to natural mortality of pentatomid and plataspid pests. Previous mermithid host records for the Pentatomidae and Plataspidae worldwide are summarized. Further work is needed to assess the impact of infection on populations over a broader range of agricultural fields and geographic localities.

Agamermis (Nematoda: Mermithidae) Infection in South Carolina Agricultural Pests

During the course of entomological investigations on natural enemies of forest pests in the Arasbaran area, northwest of Iran, a mermithid nematode, Hexamermis cf. albicans was found parasitizing the abdominal cavity of larvae of two lepidopterans, Euproctis chrysorrhoea and Lymantria dispar (Lymantriidae). Infection occurs in the early instars of the host larvae. Parasitism continues until the late instar of the larval host, when the nematode emerges and remains in a post-parasitic free-living stage until it moults into an adult. The mean body length of the parasite ranges from about 14 to 22 cm. One to four mermithids were found per host. About 34% of E. chrysorrhoea and 57% of L. dispar larvae were found to be parasitized by the nematodes. However, the frequency of the parasite varied in different areas. The infection was more frequent in dense as opposed to more sparsely forested regions. This is the first record of Hexamermis cf. albicans (Siebold, 1854) from Iran.

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First record of Hexamermis cf. albicans (Siebold, 1848) (Nematoda: Mermithidae) infecting lepidopteran larvae from Iran

The brown stink bug, Euschistus servus (Say) (Hemiptera: Pentatomidae), and other related Euschistus spp. have reached elevated pest status in the Cotton Belt of the southeastern United States. Esquivel et al. (2009) reported six species of Euschistus in Central Texas, and data presented here are a continuation of the previous study in an effort to better understand the seasonal dynamics of the six species. Fewer insecticide applications to control the boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae); implementation of genetically modified varieties of cotton, Gossypium hirsutum L., and target-specific insecticides; and resistance to insecticide (Snodgrass et al. 2005) dictate continued exploration for alternative control measures against stink bugs. Entomopathogenic nematodes have long been recognized as potential biological control agents against some insect species, including pentatomids (Nickle 1972) such as southern green stink bug, Nezara viridula (L.) (Rubtzov 1977, Laumond et al. 1979, Bhatnagar et al. 1985), Platynopus sp. (Gokulpure 1970), Rhaphigaster nebulosa (Poda) (Manachini and Landi 2003), and Aelia acuminata (L.) (Sultanov et al. 1990). Despite their association with numerous other economically important pest species (Rahaman et al. 2000), nematodes have not been previously reported as parasites of the brown stink bug. Thus, this is the first report of nematodes infecting brown stink bug adults. Pheromone-baited yellow pyramidal traps, lures, and insecticide-impregnated ear tags (Cottrell 2001) were used to collect adult brown stink bugs. Trapping sites were in pecan (Carya illinoinensis (Wangenh.) K. Koch) orchards adjacent to commercial fields of cotton, maize (Zea mays L.), or soybeans (Glycine max (L.) Merr.). Movement of stink bugs from adjacent row crops into pecan orchards had previously been observed (personal observation). In total, 12 traps were placed within pecan orchards or along the orchard interfaces with cotton or maize. At each location, three or four 182-m intervals. Traps were deployed on 9 March 2010 and serviced three times each week (Monday, Wednesday, and Friday) until fiscal resources limited the frequency of servicing traps to once per week beginning 12 October through December 2010. Lures were replaced every two weeks. Captured adults were placed in plastic freezer bags and returned to the laboratory for dissection as described by Esquivel (2011). Esquivel (2009, 2011)

https://bioone.org/journals/Southwestern-Entomologist/volume-36/issue-2/059.036.0210/Euschistus-servus-Say1--A-New-Host-Record-for-Mermithidae/10.3958/059.036.0210.pdf

Euschistus servus (Say)1 — A New Host Record for Mermithidae (Mermithida)

A juvenile specimen of a mermithid (Nematoda) was found parasitizing a third instar nymph of Triatoma sordida from Mato Grosso, Brazil. This is the first record of mermithid parasitism in a triatomine species. The Mermithidae represents a family of nematodes that are specialized insect parasites. Entomonematodes are one of the highly influential agents regulating the population dynamics of insects. This report introduces the opportunity to think about mermithids as a possible candidate for use as triatomine biological control.

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First record of a mermithid worm (Nematoda, Mermithidae) parasitizing a third instar nymph of Triatoma sordida (Stål, 1859) (Hemiptera, Reduviidae, Triatominae) from Mato Grosso, Brazil.

Numerical treatment of temporal-fractional porous medium model occurring in fractured media

Hosts of mermithids - the most important pests of farm and forest plants in Uzbekistan.

The work is devoted to developing the parallel algorithms for solving the initial boundary problem for the time-fractional diffusion equation. After applying the finite-difference scheme to approximate the basis equation, the problem is reduced to solving a system of linear algebraic equations for each subsequent time level. The developed parallel algorithms are based on the Thomas algorithm, parallel sweep algorithm, and accelerated over-relaxation method for solving this system. Stability of the approximation scheme is established. The parallel implementations are developed for the multicore CPU using the OpenMP technology. The numerical experiments are performed to compare these methods and to study the performance of parallel implementations. The parallel sweep method shows the lowest computing time.

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Parallel Direct and Iterative Methods for Solving the Time-Fractional Diffusion Equation on Multicore Processors

On a Nonlocal Boundary Value Problem for a Three-dimensional Tricomi Equation in a Prismatic Unbounded Domain

Abstract In this paper, we propose a method for inpainting regular textures composed of oriented patterns and completion of images distorted by long stripes. We have developed a model fit to describe a regular texture as a sum of a few ridge functions. The ridge functions are known in tomography as a result of a back-projection operator applied to projections, or samples of the Radon transform. A computational scheme for the singular value decomposition of a regular texture into the sum of informative ridge functions is presented. The numerical experiments on various images demonstrate the efficiency of the techniques proposed.

M. A. Sultanov

Papers

Hosts of mermithids - the most important pests of farm and forest plants in Uzbekistan.

Parallel Direct and Iterative Methods for Solving the Time-Fractional Diffusion Equation on Multicore Processors

On a Nonlocal Boundary Value Problem for a Three-dimensional Tricomi Equation in a Prismatic Unbounded Domain

Inpainting of regular textures using ridge functions

Efficient Parareal algorithm for solving time-fractional diffusion equation