Jesus F. Esquivel

Transmission of cotton seed and boll rotting bacteria by the southern green stink bug (Nezara viridula L.).

Aims:  To determine the ability of the southern green stink bug (SGSB) (Nezara viridula L.) to transmit Pantoea agglomerans into cotton (Gossypium hirsutum) bolls.

Comparative peptidomics of four related hemipteran species: Pyrokinins, myosuppressin, corazonin, adipokinetic hormone, sNPF, and periviscerokinins

We performed the first comprehensive peptidomic analysis of neurohormones from hemipteran insects by analyzing the neuropeptides of two major neurohemal organs, namely the corpora cardiaca and abdominal perisympathetic organs. For the experiments we selected four related species of polyphagous stinkbugs (Pentatomidae), three of which are known to attack several important food crops. Peptide sequences were identified by MALDI-TOF mass spectrometry; tandem fragmentation of myosuppressin, sNPF, CAPA-periviscerokinins and pyrokinins revealed novel sequences not known from other insects so far. Most Leu/Ile and Glu/Lys ambiguities could be solved by either specific side-chain fragmentations or on-plate acetylation experiments. The identification of the specific sequences provides a solid basis for forthcoming pharmacological tests to study the neuroendocrine system of these pest insects. However, it should be mentioned in this context that the sequences of the peptides from different stinkbugs are likely not representative of Hemiptera in general. The forthcoming release of the genome from the reduviid Rhodnius prolixus will provide sufficient data to clear this point.

Temporal analysis of cotton boll symptoms resulting from southern green stink bug feeding and transmission of a bacterial pathogen.

ABSTRACT The southern green stink bug, Nezara viridula (L.), is a significant pest of cotton, Gossypium hirsutum L., and is becoming an increasing challenge due to the decrease in use of broad-spectrum insecticides on the crop. The southern green stink bug can vector an opportunistic Pantoea agglomerans strain (designated Sc 1-R) into cotton bolls, resulting in infection. The appearance of stink bug damage varies, and pest managers cannot readily identify its source. This research reports a systematic depiction of green, immature boll responses at various stages of maturity (1, 2, and 3 wk post-anthesis [WPA]) to stink bug injury and to infection by the vectored cotton pathogen by demonstrating the progression of effects 1, 2, and 3 wk after exposure (WAE). When laboratory-reared adult southern green stink bug not harboring Sc 1-R deposited bacteria into greenhouse-grown bolls at 1, 2, or 3 WPA during feeding/probing, bacteria reached concentrations of 109, 109, and 103 colony-forming units (CFUs)/g tissue, respectively, at 3 WAE, yet caused minimal seed and lint damage regardless of the age of the bolls that were penetrated. Bolls at a maturity of 1 or 2 WPA showed similar susceptibility when exposed to stink bugs that vectored Sc 1-R. After a week of infection, seeds were salmon-pink with normal white lint and up to 104 CFUs/g tissue when Sc 1-R was detected. Necrosis of the entire inoculated locule(s) with a maximum Sc 1-R concentration detected at 108 CFUs/g tissue occurred in samples harvested 2 or 3 WAE. Conversely, seed and lint deterioration due to the transmitted opportunist into bolls exposed 3 WPA was confined to the puncture site. In summary, after a week of development, bolls were tolerant to southern green stink bug feeding/ probing damage and to nonpathogenic bacteria, but they were severely damaged when the opportunistic pathogen Sc 1-R was transmitted. At 3 WPA, the fruit was immune to the spread of the pathogen with infections confined to the puncture site.

The Acquisition and Internalization of Salmonella by the Lesser Mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae)

In poultry broiler production facilities, it is important to understand the sources and contribution of reservoir populations of pathogens. The lesser mealworm beetle, Alphitobius diaperinus (Panzer), is a common pest in poultry litter that is reported to carry pathogens affecting both human and animal health. This study investigates whether the carriage of a bacterial pathogen occurs by the harboring of bacteria internally by these insects. Beetles were exposed to a marker bacterium, Salmonella enterica serovar Typhimurium-green fluorescent protein (ST-GFP), at concentrations up to 10(7) colony-forming units (cfu)/mL for 0.5 to 12 h, and then subsequently surface disinfected and dissected. The head, gastrointestinal tract and hemolymph were cultured for the presence of ST-GFP. This study definitively demonstrates the internal carriage of Salmonella by this insect and found that the beetles rapidly acquired bacteria from external sources and harbored the bacteria within their alimentary canal after exposure for 30 min at 10(4) cfu/mL and within the hemolymph after exposure for 2 h at 10(6) cfu/mL. Beetles internalized an average of 9.5 × 10(1) and 3.2 × 10(3) after a 2-h exposure to 2 × 10(4) and 2 × 10(6) cfu/mL, respectively. The lesser mealworm is a serious pest within the poultry brooder and laying industry and because of their mobility, voracious feeding habits, and prey potential may represent an active source facilitating the dissemination of Salmonella.

Identification of the first neuropeptides from the CNS of Hemiptera: CAPA peptides of the southern green stinkbug Nezara viridula (L.).

A direct mass spectrometric investigation of nerve homologs of the abdominal perisympathetic organs was employed to reveal the first and complete sequences of CAPA peptides from a hemipteran species, the southern green stinkbug Nezara viridula. Side-chain fragmentations allowed the assignment of internal Leu/Ile; on-plate acetylation was used to distinguish between the mass-related Lys and Gln. The following sequences were obtained: DQLFPFPRV-NH(2) (CAPA-PVK-1), EQLIPFPRV-NH(2) (CAPA-PVK-2), and NGSAGNGGLWFGPRL/I-NH(2) (CAPA-PK). CAPA-PVKs are associated with the regulation of diuresis in insects, and identification of those native to a hemipteran will provide the experimental basis to better understand regulation of water balance in this family of insects.

Southern Green Stink Bugs (Hemiptera: Pentatomidae) as Vectors of Pathogens Affecting Cotton Bolls — A Brief Review

Abstract. The southern green stink bug, Nezara viridule L., is a member of the stink bug complex that has become more economically important in cotton, Gossypium hirsutum L., production in recent years. A disease of cotton bolls, identified as South Carolina boll rot, seemed coincidental to the increase in abundance of stink bugs. The relationship between the occurrence of the cotton disease and the southern green stink bug is discussed here. This review documents: the identification and description of the disease; potential causal agents and insect vectors; conclusive identification of Pentoea egglomerans (Ewing and Fife) Gavini et al. as the causative agent of the disease; establishment of southern green stink bug as a model insect based on ingestion, retention, and transmission of the disease to cotton bolls; determination of vulnerability of bolls of different ages to disease; and, transmission of other disease agents by southern green stink bugs. Future research needs also are discussed.

Analysis of Microscopic Injuries Caused by Southern Green Stink Bug (Hemiptera: Pentatomidae) Feeding on Cotton Bolls

Abstract. The southern green stink bug, Nezara viridula (L.), utilizes stylets while feeding to pierce the wall of a boll of cotton, Gossypium hirsutum L., and can inoculate disease-causing pathogens into developing green bolls. Detection of diseased bolls is difficult because the surface of the carpel wall frequently lacks apparent macroscopic evidence of insect feeding regardless of infection; blisters on the interior surface of the carpel wall are commonly masked by darkened necrotic tissue. The objectives of this study were to characterize microscopic evidence of feeding by laboratory-reared southern green stink bugs on greenhouse-grown cotton bolls and to use these findings to aid in detection of feeding evidence by piercing-sucking insects on field-collected bolls from four southeastern states. Microscopic analyses of greenhouse-reared bolls fed upon by southern green stink bug (n = 40) yielded definitive characteristics and imagery of feeding evidence. Salivary flanges on the exterior surface of the boll and blisters at the feeding site on the interior surface of the carpel wall were characteristic of feeding by southern green stink bug. Also, salivary flanges were associated with all external puncture wounds on the boll wall. These characteristics were used as the baseline to detect feeding by feral piercing-sucking pests on field-grown bolls during the 2008 and 2009 production seasons. Injury characteristics from field-grown bolls were comparable to characteristics observed in greenhouse-reared bolls after feeding by southern green stink bug. A few field-collected bolls (5%; n = 160) possessed discolored seeds and exhibited evidence of boll feeding externally but lacked blisters on the interior surface of the carpel wall, thus suggesting an incomplete breach of the interior carpel wall. Callus tissue, colloquially termed a ‘wart,’ on the interior surface of the boll carpel wall is typically associated with feeding by stink bugs but was not detected in bolls grown in a greenhouse and was only sporadically detected in bolls collected from the field. When present, callus tissue was always associated with an external puncture. This is the first study to unequivocally illustrate microscopic characteristics associated with feeding damage by southern green stink bug on cotton bolls. Findings are discussed in relation to evidence of feeding by insects in field-collected bolls of unknown age and history.

Species of Stink Bugs in Cotton and Other Row Crops in the Brazos River Bottom of Texas

Abstract. Stink bugs have recently become an economic pest of cotton, Gossypium hirsutum L., in the Brazos River Bottom production area of Texas, but many producers remain uncertain which species are infesting fields. Cotton and nearby maize (Zea mays L.), sorghum [Sorghum bicolor (L.) Moench], and soybean [Glycine max (L.)] fields were sampled weekly for stink bugs in 2011 and 2012 to determine the complex of species infesting cotton and identify other crops in which stink bugs may develop and then move to cotton. In total, 12 phytophagous stink bug species were collected among the four crops over both years. Seven species were detected in cotton, but the brown stink bug, Euschistus servus (Say), and redshouldered stink bug, Thyanta custator acerra McAtee, collectively, accounted for 80 and 96% of the stink bugs found in 2011 and 2012, respectively. The two species also were the most prevalent encountered in soybean and maize over both years. The absence of southern green stink bug, Nezara viridula (L.), during both years and absence of green stink bug, Acrosternum hilare (Say), in 2012 are interesting because both species were commonly observed in cotton and soybean fields in years before the initiation of the study. Given the prevalence of brown and redshouldered stink bugs in cotton and relative abundance of both species in soybean and, to a lesser extent, maize, soybean and maize might be late-season sources for stink bugs in cotton.

A visual guide for identification of Euschistus spp. (Hemiptera: Pentatomidae) in Central Texas.

Stink bugs have become problematic in cotton, Gossypium hirsutum L., following efforts by Boll Weevil Eradication Programs. These programs have led to a reduced number of insecticide applications that normally suppressed stink bugs. Several phytophagous species of Euschistus in cotton and other crops are often grouped into the “brown stink bug complex.” However, this does not enable accurate identification of individual Euschistus species; unlike the southern green stink bug, Nezara viridula L., and green stink bug, Acrosternum hilare Say, which are relatively easy to identify in the field. In addition to their similarities in coloration causing potential problems with identification, brown stink bugs are less susceptible to certain classes of insecticides (Snodgrass et al. 2005). Dichotomous keys are available for identifying Euschistus spp. (Rolston 1974, McPherson and McPherson 2000) but are not helpful for accurate and rapid identification of stink bugs in the field. Because of the advanced stage of the Boll Weevil Eradication Program in the Blacklands region, known tolerances to certain classes of insecticides, and seemingly apparent similarities between species, this study was undertaken to identify Euschistus spp. in Central Texas and provide a visual guide for accurate identification in the field. From January 2007 through January 2009, five black-light and two pheromone-baited traps were used to collect adult brown stink bugs in Central Texas (Burleson County). Traps were placed in or near pecan, Carya illinoinensis (Wangenh.) K. Koch, orchards adjacent to fields previously planted with maize, Zea mays L.; cotton; or soybeans, Glycine max (L.) Merr. Traps were serviced three times a week, and captured adults were taken to a laboratory where dichotomous keys of Rolston (1974) and McPherson and McPherson (2000) were used for identification. Voucher specimens (Accession Number 672) were confirmed and cataloged by Ed G. Riley, Museum Curator, Department of Entomology, Texas A&M University, College Station, TX. Six Euschistus species were identified in the region (Fig. 1). The absence of spots in the membranous area of the hemelytra (Fig. 1A, inset upper right) is the key characteristic for distinguishing E. quadrator Rolston from other species. Spots in the membranous area (Fig. 1B, inset upper right) or in confluence with (i.e., in line with) venation of the hemelytra are present in the other five species. Similar to E. quadrator, E. tristigmus (Say) has a unique character in the presence of large median black spot(s) on the abdominal venter (Fig. 1B, inset lower right) that can be used to distinguish this species from all others in the region.

Poultry litter and the environment: Physiochemical properties of litter and soil during successive flock rotations and after remote site deposition.

The U.S. broiler meat market has grown over the past 16 years and destinations for U.S. broiler meat exports expanded to over 150 countries. This market opportunity has spurred a corresponding increase in industrialized poultry production, which due to the confined space in which high numbers of animals are housed, risks accumulating nutrients and pollutants. The purpose of this research was to determine the level of pollutants within poultry litter and the underlying soil within a production facility; and to explore the impact of spent litter deposition into the environment. The study follows a production facility for the first 2.5 years of production. It monitors the effects of successive flocks and management practices on 15 physiochemical parameters: Ca, Cu, electrical conductivity, Fe, K, Mg, Mn, moisture, Na, NO3(-)/N, organic matter, P, pH, S, and Zn. Litter samples were collected in-house, after clean-outs and during stockpiling. The soil before house placement, after the clean-outs and following litter stockpiling was monitored. Management practices markedly altered the physiochemical profiles of the litter in-house. A canonical discriminant analysis was used to describe the relationship between the parameters and sampling times. The litter profiles grouped into five clusters corresponding to time and management practices. The soil in-house exhibited mean increases in all physiochemical parameters (2-297 fold) except Fe, Mg, %M, and pH. The spent litter was followed after deposition onto a field for use as fertilizer. After 20 weeks, the soil beneath the litter exhibited increases in EC, Cu, K, Na, NO3(-)/N, %OM, P, S and Zn; while %M decreased. Understanding the impacts of industrialized poultry farms on the environment is vital as the cumulative ecological impact of this land usage could be substantial if not properly managed to reduce the risk of potential pollutant infiltration into the environment.