Gross Morphology of Diseased Tissues in Nezara viridula (Hemiptera: Pentatomidae) and Molecular Characterization of an Associated Microsporidian.

Nezara viridula (L.) (Hemiptera: Pentatomidae), commonly known in the U.S. as the southern green stink bug (SGSB), is a cosmopolitan, highly polyphagous feeder that causes severe damage to a wide range of agronomically important crops such as fruit, vegetable, grain, tobacco, and cotton, throughout much of the United States, and is a global pest of considerable ecological, agricultural, and economical interest. During dissection of female Nz. viridula, conspicuous black and brown spots or lesions were observed on various internal organs. To determine the cause of these spots or lesions, tissues of fat body, spermatheca, ovaries, and ovulated eggs were collected from healthy and infected individuals. The gross morphology of the spots was characterized, and the microorganisms associated with the infection were identified by amplicon sequencing of the V4 region of the small subunit rRNA gene. The presence of a microsporidian pathogen Nosema maddoxi, Becnel, Solter, Hajek, Huang, Sanscrainte, & Estep (Microsporidia: Nosematidae) which has been observed on other species of stink bug, was evidenced for the first time. The characterization of the gross morphology of this associated microsporidian may enable more rapid determination of microsporidia infection in stink bug colonies and field populations.

Trypanosomatids Associated in the Alimentary Canal of Bagrada hilaris (Hemiptera: Pentatomidae).

Bagrada hilaris (Burmeister) is an invasive pest of economically important crops in the United States. During physiological investigations of B. hilaris, a flagellated protozoan was discovered in the alimentary canal of many specimens. This manuscript characterizes the morphology and molecular identification of the trypanosomatid, which appears similar to trypanosomatids identified in other stink bug species. It has been identified as a species in the Blastocrithidia genus based on morphological characteristics and molecular analyses.

Female Reproductive System Morphology and the Development of a Physiological Age-Grading System for Bagrada hilaris (Hemiptera: Pentatomidae).

In this paper, we describe the morphology of the female Bagrada hilaris (Burmeister) reproductive system and develop a physiological age-grading system related to egg production. The female reproductive system is composed of two meroistic and telotrophic ovaries each containing 5-6 tubular ovarioles. The ovarioles unite into the lateral oviduct which combine to form the common oviduct. The ovarioles are composed of two regions; the distal germarium and the tubular vitellarium which contains maturing follicles. Each follicle is surrounded by a layer of cells; the follicular epithelium. As the follicle passes from the ovariole to the lateral oviducts the follicular epithelial cells slough off and accumulate in the base of the ovarioles and are known as follicular relics. The continuum of ovarian development is divided into two categories: nulliparous ('nonreproducing') and parous ('reproducing'). The nulliparous category is characterized by the absence of follicular relics or eggs in the oviducts as opposed to the parous category where follicular relics and, in many cases, eggs occurred in the oviducts. The nulliparous category is divided further into two stages; N1 and N2 based on ovariole differentiation. The parous category is divided into three stages; P1, P2, and P3, based on the quantity and appearance of follicular relics. Females characterized as P3 produced three times more eggs (79.2 eggs ± 5.7) than females characterized as P1 (27.1 eggs ± 6.0).

Antimicrobial properties of nest volatiles in red imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae).

The antimicrobial property of volatiles produced by red imported fire ants, Solenopsis invicta, against Beauveria bassiana, a common entomopathogenic fungus, was demonstrated. The germination rate of B. bassiana spores was significantly reduced after they were exposed to volatiles within an artificial ant nest. Since the air that contained the same level of O2 and CO2 as that in artificial fire ant nests did not suppress the germination rate of B. bassiana, the observed reduction of germination rate must be caused by the toxicity of nest volatiles. Nest fumigation may be an important component of the social immune system in S. invicta.

Efficacy of water-dispersible formulations of biological control strains of Aspergillus flavus for aflatoxin management in corn.

Field experiments were conducted in 2011 and 2012 to evaluate the efficacy of water-dispersible granule (WDG) formulations of biocontrol strains of Aspergillus flavus in controlling aflatoxin contamination of corn. In 2011, when aflatoxin was present at very high levels, there was no WDG treatment that could provide significant protection against aflatoxin contamination. The following year a new WDG formulation was tested that resulted in 100% reduction in aflatoxin in one field experiment and ≥ 49% reduction in all five WDG treatments with biocontrol strain 21882. Large sampling error, however, limited the resolution of various treatment effects. Corn samples were also subjected to microbial analysis to understand better the mechanisms of successful biocontrol. In the samples examined here, the size of the A. flavus population on the grain was associated with the amount of aflatoxin, but the toxigenic status of that population was a poor predictor of aflatoxin concentration.