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Although campylobacteriosis caused by Campylobacter jejuni and Campylobacter coli has been increasingly reported worldwide owing to the consumption of contaminated poultry and fresh produce, the current detection protocols are not selective enough to inhibit unspecific microbes other than these pathogens. Five antibiotics were separately added to Bolton broth, and the survival rates of 18 Campylobacter spp. and 79 non-Campylobacter spp. were evaluated. The survival rate of the non-Campylobacter spp. was the lowest in Bolton broth with rifampin (6.3%), followed by cefsulodin (12.7%), novobiocin (16.5%), and potassium tellurite and sulfamethozaxole (both 17.7%). Also the most effective concentration of rifampin was found to be 12.5 mg/L, which markedly inhibited non-Campylobacter strains while not affecting the survival of Campylobacter strains. After the Campylobacter spp. were enriched in Bolton broth supplemented with 12.5 mg/L rifampin (R-Bolton broth), CampyFood Agar (CFA) was found to be better in selectively isolating the pathogens in the enrichment broth than the International Organization for Standardization method of using modified charcoal cefoperazone deoxycholate agar (mCCDA) for this step. When applied to natural food samples-here, romaine lettuce, pepper, cherry tomato, Korean leek, and chicken-the R-Bolton broth-CFA combination decreased the number of false-positive results by 50.0, 4.2, 20.8, 50.0, and 94.4%, respectively, compared with the International Organization for Standardization method (Bolton broth-mCCDA combination). These results demonstrate that the combination of R-Bolton broth and CFA is more efficient in detecting C. jejuni and C. coli in poultry and fresh produce and thus should replace the Bolton broth-mCCDA combination.

Antagonistic microbes were isolated from soils to control mycotoxin contamination of cereals by limiting the growth of mycotoxigenic Fusarium species. In total, 341 bacterial isolates were examined for antifungal activity against eight mycotoxigenic Fusarium species using dual culture assays. The screening identified 11 isolates that inhibited mycelial growth of all Fusarium species tested. The culture filtrates of 2 of the 11 isolates completely inhibited germination of conidia up to 21 days of incubation. These two isolates exhibited identical activity toward the fungi tested and were identified as Brevibacillus spp. based on 16S rRNA sequence homology. The most closely related species based on phylogenetic analysis was Brevibacillus reuszeri. Additional dual culturing using further fungal species showed that the antagonistic Brevibacillus inhibited the growth of most Fusarium species tested (39 of 46 species), two Epicoccum spp., one Alternaria sp., three Aspergillus spp. (3 of 11), and three Penicillium spp. (3 of 8). The in vivo assay was performed to test the efficacy of antagonistic Brevibacillus isolates on maize ears and revealed that the application of microbes suppressed ear rot (ANOVA, p = 0.0020). This Brevibacillus sp. may be an antagonist of the majority of Fusarium species, including mycotoxigenic species.

This study investigated the effect of adaptation of Staphylococcus aureus strains to the acidic condition of tomato in response to environmental stresses, such as heat and acid. S. aureus ATCC 13565, ATCC 14458, ATCC 23235, ATCC 27664, and NCCP10826 habituated in tomato extract at 35°C for 24 h were inoculated in tryptic soy broth. The culture suspensions were then subjected to heat challenge or acid challenge at 60°C and pH 3.0, respectively, for 60 min. In addition, transcriptional analysis using quantitative real-time PCR was performed to evaluate the expression level of acid-shock genes, such as clpB, zwf, nuoF, and gnd, from five S. aureus strains after the acid habituation of strains in tomato at 35°C for 15 min and 60 min in comparison with that of the nonhabituated strains. In comparison with the nonhabituated strains, the five tomato-habituated S. aureus strains did not show cross protection to heat, but tomato-habituated S. aureus ATCC 23235 showed acid resistance. In quantitative real-time-PCR analysis, the relative expression levels of acid-shock genes (clpB, zwf, nuoF, and gnd) were increased the most in S. aureus ATCC 23235 after 60 min of tomato habituation, but there was little difference in the expression levels among the five S. aureus strains after 15 min of tomato habituation. These results indicate that the variation of acid resistance of S. aureus is related to the expression of acid-shock genes during acid habituation.

Development of immature Thrips palmi Karny was investigated at 12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, and 35℃, 20?40% RH and a photoperiod of 14:10 (L:D) h. Developmental time decreased with increasing temperature up to 32.5℃ in all stages. The total developmental time was longest at 12.5℃ (64.2 days) and shortest at 32.5℃ (9.2 days). The lower developmental threshold was 10.6, 10.6, 9.1, and 10.7℃ for egg, larva, prepupa, and pupa, respectively. The thermal constant required to complete the respective stage was 71.7, 59.2, 18.1, and 36.8DD. The lower threshold temperature and thermal constant were 10.6℃ and 183.3DD, respectively, for total immature development. The nonlinear relationship between developmental rate and temperature was well described by the modified Sharpe and DeMichele biophysical model (r 2 =0.905?0.998). The distribution of developmental completion of each stage was described by the 3-parameter Weibull function (r 2 =0.855?0.927). The temperature-dependent developmental models of T. palmi developed in this study could be used to predict its seasonal phenology in field and greenhouse vegetable crops.

Trichogramma wasps parasitize eggs of various insect species. Several Trichogramma species have been commercialized to manage Lepidopteran agricultural pests. Correct species identification is essential for successful biological control. However, the microscopic size and morphological similarity of Trichogramma species makes correct identification very difficult. Internal transcribed spacer (ITS)-2 gene sequences have been used to identify Trichogramma species. Using this molecular marker, Trichogramma species that are commercially available in Korea were identified as Trichogramma ostriniae and Trichogramma brassicae. The latter has not previously been reported in Korea. Additionally, Cadra cautella and Sitotroga cereallela eggs (host eggs of the commercialized Trichogramma species in Korea) were infected with Wolbachia. However, Trichogramma were not infected with the bacterium. This indicates that horizontal transfer of Wolbachia does not occur from host to wasp.

Accurate forecasting of pest density is essential for effective pest management. In this study, a simple image processing system that automatically estimated the density of whiteflies on sticky traps was developed. The estimated densities of samples in a laboratory and a greenhouse were in accordance with the actual values. The detection system was especially efficient when the whitefly densities were at medium to high levels, however, the development of identification algorithms and more appropriate collection methods may improve the image processing system. Taken together, the results of this study indicate that the image processing system described here may be useful for evaluating the population dynamics.

We investigated, via atomic force microscopy and transmission electron microscopy, the effect of oscillatory shearing amplitude ( γ 0 ) and frequency ( ω ) on the interfacial morphology of a reactive bilayer polymer system composed of end-functionalized polystyrene with carboxylic acid (PS-mCOOH) and poly(methyl methacrylate- ran -glycidylmethacrylate) (PMMA–GMA). It has been observed that in the absence of oscillatory shearing (or at very small values of γ 0 and ω ), the roughness of the interface increased with reaction period, while at large values of γ 0 and ω it became less than that observed in the absence of oscillatory shearing. This observation may be attributable to the possibility that oscillatory shearing might have hindered the diffusion of polymer chains, which are located away from the interface, to the interface of the layers. However, the effect of γ 0 and ω on the roughness of the interface of (PS-mCOOH)/(PMMA–GMA) bilayer is found to be quite different. Specifically, when a large γ 0 was first applied to the bilayer, followed by application of a low γ 0 , the reactive polymer chains diffused into the interface of the (PS-mCOOH)/(PMMA–GMA) bilayer; and then the roughness of the interface increased. However, when a high ω of oscillatory shear flow was first applied to a specimen, followed by application of a low ω of oscillatory shear flow to the same specimen, a relatively low degree of roughness of the interface was observed. This is attributable to the fact that the oscillatory shear with a large ω generated a multilayer microstructure consisting of PS and PMMA layers, which apparently played the role of an obstacle (or diffusion barrier) that hindered the diffusion of both reactive polymer chains to the interface for chemical reactions.

A trigonometric approximation was used to describe the head shape of common vegetable-feeding aphids, Aphis gossypii Glover, Aulacorthum solani (Kaltenbach), Brevicoryne brassicae (Linne), Macrosiphum euphorbiae (Thomas), and Myzus per-sicae (Sulzer). After acquiring and standardizing digital images of the alate aphids, a frontal curve was represented as a set of points in a given domain, -π/2 ≤ x ≤ π/2. Then, the points were approximated by the function, y = a 0 + ∑ n = 1 45 ( a 2 n − 1 cos ( 2 n − 1 ) x + a 2 n sin 2 n x ) π Coefficients of the function were calculated by multiple regression analysis, and the averages of coefficients were used to reconstruct the generalized shape of each species.

A new improved diet, supplemented with fine sand, onion juice and distilled water, prevented diet from hardness and cracking, and resulted in a successful mass rearing of Delia antiqua (Meigen) and Delia platura (Meigen) for the larval development. Optimal dose of cobalt 60 gamma ray was 3 kilo-rad for sufficient sterilization of pupae of D. antiqua and D. platura. Mature sperms were not found in testes of the treated D. antiqua and D. platura , but well-developed sperms were observed in normal males. Release of sterile onion flies efficiently lowered the percentage of damaged garlic plants in greenhouse.