Artificial Feeding Systems for Plant-Parasitic Nematodes

Feeding of an "obligate" plant-parasitic nematode (nonfungal feeder), Pratylenchus scribneri, in the absence of plant tissue was demonstrated in an artificial system consisting of liquid media and indicator dyes including amaranth and various nontoxic food colors. Among the compounds tested, sucrose, dextrose, Gamborg''s B5 medium, and DL-methionine stimulated a small percentage of feeding (12-36%). A high percentage of feeding (90-100%) occurred in a filtrate from excised corn roots cultured in Gamborg''s B5 medium. This feeding system has the potential to develop an artificial medium for plant-parasitic nematodes and to screen novel nematicides that are stomach poisons.     

Medfly eradication in California:

The impact of malathion-bait sprays (directed against medfly, Ceratitis capitata [Wiedemann]) on an endemic gall midge (Rhopalomyia californica Felt) and its parasitoids was investigated during 1982–83 in the south San Francisco Bay area of northern California. In a heavily sprayed area (Woodside), a population explosion of the midge was detected following 24 applications of malathion bait. The midge population reached levels ca. 90x greater than those observed in an adjacent unsprayed area (Jasper Ridge). In a moderately sprayed area (Portola Valley), the midge population increased as much as 5x that observed in the adjacent unsprayed area (Jasper Ridge), following 12 applications of malathion bait. In laboratory tests, the malathion bait was toxic to both the midge and its parasitoids. The major parasitoids were Torymus koebelei (Huber), Zatropis capitis Burks, Platygaster californica (Ashmead) and Mesopolobus sp. Population increases of the midge following malathion-bait sprays were attributed to destruction of parasitoids and other natural enemies of the midge. If the environmental impact of malathion-bait sprays is related to the number of applications (as suggested in this study), then it would be worthwhile to determine the appropriate bait-spray strategy for a given situation, so as to minimize adverse effects on nontarget species, yet insure suppression or eradication of medfly.

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Résumé L'impact des pièges tratiés au malathion (destinés à Ceratitis capitata Wiedem) sur Rhopalomyia californica Felt et ses parasitoïdes a été examiné en 1982–1983 dans le sud de la zone de la baie de San Francisco en Californie. Dans une zone fortement traitée (Woodside), une explosion de population a été décelée après 24 traitements. La population de R. californica a atteint des niveaux 90 fois supérieurs à ceux observés dans une zone contiguë non traitée (Jasper Ridge). Dans une zone modérément traitée (Portola Valley), avec 12 traitement, la population de R. californica a atteint jusqu'a 5 fois celle de Jasper Ridge. Au laboratoire, le piège à malathion a été toxique tant pour R. californica que pour ses parasitoïdes, dont les principaux étaient: Torymus koebelei (Huber), Zatropis capitis Burks, Platygaster californica(Ashmead) et Mesopolobus sp. L'accroissement de la population de C. capitata après traitement a été attribué à la destruction de parasitoïdes et d'autres ennemis naturels. Si l'effet su l'environnement du traitement est lié au nombre d'interventions (comme le suggère cette étude), alors cela vaudrait la peine de définir une stratégie de traitement appropriée à une situation donnée, de façon à minimiser les effets négatifs sur des espèces non visées, tout en assurant la suppression ou l'éradication de C. capitata.

     

Modification of plant bait technique for direct diagnosis for Rhizoctonia rice pathogens from Myanmar paddy field soils

A modified baiting technique was conducted for selective isolation, fungal DNA diagnosis and fungal cell lipid assay derived from Myanmar isolates of Rhizoctonia spp., causal agents of rice sheath diseases by trapping selective plant stem segments. Bait plant materials of rice, mat rush and cotton were successfully used to isolate R. solani AG1-IA, R. oryzae and R. oryzae-sativae. Moreover, the three plant materials were also effectively used to detect genomic DNA derived from all Rhizoctonia spp. obtained from Myanmar. Rice segment was the most successful materials for detection of fungal cell lipids including palmitic, stearic and linoleic acids. The results of this experiment demonstrate that bait plant materials of rice, mat rush and cotton were the best useful tools for not only direct isolation, but also fungal DNA diagnosis and cell lipid assay of Myanmar soil environmental conditions.     

Toxicity of baited spinosad formulations to Ceratitis capitata: from the laboratory to the application

GF‐120, a fruit fly bait designed to attract and kill adult fruit flies, was tested in the laboratory and outdoors to determine effects of pre‐treatment diet and bait aging on mortality of Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). Two spinosad‐based compounds, GF‐120 and Tracer^® Ultra, had generated two distinctive dose–mortality responds, with LC⁸⁰, LC⁹⁰, and LC⁹⁹ values of 2.4, 2.8, and 4.1 p.p.m., and 255, 479, and 1 143 p.p.m., respectively. The residues of GF‐120 drops, after feeding to the flies, generated 14.3% mortality. The droplet size of the baited spray plays an important role. The toxicity of large drops lasted more than that of small droplets. In the field, exposure to the sun further deteriorates the compound, which lost 50% of its toxicity within 6 days. Disappearance of the compound in the field, due to consumption by various insects, also played a role as 50% of the GF‐120 drops disappeared within 7 days. As mortality was directly related to the amount of insecticide eaten, the effect of GF‐120 depended on the feeding status of the flies: well‐fed flies were almost unaffected compared with starved ones.     

五种假单胞菌的分离鉴定及其生物活性

【目的】从湖南长沙市采集到的土样中分离假单胞菌并进行归类,研究各菌株抑菌和抗肿瘤生物活性,以丰富假单胞菌菌种资源并为微生物次级代谢物的挖掘奠定基础。【方法】采用大蜡螟诱集法诱集分离假单胞菌,结合形态观察、生理生化特征和16S rRNA基因序列同源性分析,鉴定并归类各细菌,通过平板扩散法、对峙培养法和肿瘤细胞毒性试验分别研究各菌株抑制细菌、拮抗真菌和抗肿瘤细胞等生物活性。【结果】从湖南长沙市郊区菜地、林地中分离得到5株假单胞菌,归类并命名为Pseudomonas protegens CY01、绿针假单胞菌CY02(Pseudomonas chlororaphis CY02)、栖稻假单胞菌CY04(Pseudomonas oryzihabitans CY04)、Pseudomonas sp.CY05和恶臭假单胞菌CY06(Pseudomonas putida CY06)。P.protegens CY01和P.chlororaphis CY02对枯草芽胞杆菌(Bacillus subtillis)和金黄色葡萄球菌(Staphylococcus aureus)具有较好的抑菌效果,P.chlororaphis CY02对水稻稻瘟病菌(Pyricularia oryzae)具有良好的拮抗作用,对小鼠黑色素瘤细胞B16具有较强的细胞毒性。【结论】分离得到的P.chlororaphis CY02,在抑制病原细菌、拮抗水稻稻瘟病菌和抗肿瘤细胞等方面具有显著效果。     

A method to study slug predation on seedlings in the field

Dandelion is a common Asteraceae species that populates disturbed sites and gaps within swards where it becomes an important competitor of grasses. The natural control against dandelion includes seedling predation, with slugs, particularly Arion lusitanicus, being the most important in the Czech Republic. However, the study of slug seedling consumption is difficult because naturally established seedlings are not always available. Therefore, we developed a method of exposing laboratory‐grown seedlings as bait for slug predation. Dandelion seeds were sown in plastic cups containing a bottom layer of moist substrate. The emerged seedlings were thinned to 20 and displayed in an open area. During 2008–2010, the seedling baits were placed at 15 sites at 1 month intervals throughout the dandelion vegetative season, in parallel with plasticine baits that monitored slug feeding activity. For each 1 month interval, seedling survival was observed for a period of 8 days, and the estimated time to death was calculated; the percentage of surviving seedlings was then recorded. This method of seedling presentation demonstrated that local and temporal variation in seedling survival is correlated with slug feeding activity. The advantage of this technique is that the seedlings in baits may be presented at any place and time, as required by the experimental design; however, we found that the estimated time to seedling death was shorter for the exposed baits than for the naturally established seedlings. The method is suitable for the study of plant species other than dandelion, and also for aims other than the study of spatiotemporal trends in seedling consumption by slugs.     

Factors affecting the efficacy of a vinegar trap for Drosophila suzikii (Diptera; Drosophilidae)

Drosophila suzukii, Matsumura, is a relatively new pest in the United States attacking a variety of fruit crops. Studies were conducted to develop a standardized, economical trap for monitoring. Laboratory bioassays found that flies were attracted to dark colours ranging from red to black. Similarly, fly catches in 237‐ml plastic ‘spice’ jars with ten 0.48‐cm holes and baited with apple cider vinegar were significantly higher in jars with red or black than white caps. The use of an alternating set of three, horizontal red, black and red bands (‘Zorro’ trap) significantly increased fly catches compared with the use of all‐red or all‐black strips. This increase was associated with a significantly higher proportion of flies first landing on the side near the openings of the trap instead of on the cap with the ‘Zorro’ trap compared with the other traps. Laboratory data were used to develop a predictive model to define total fly capture as a function of trap colour/colour pattern, cumulative area of entry holes and the length of the trapping portion of the trap. Total fly catches by the ‘Zorro’ trap were compared with other red and clear plastic traps in five field trials conducted in several cultivated and uncultivated sites. Comparisons included a commercial red‐capped 200‐ml trap with two 0.63‐cm holes, an all‐red spice jar with ten 0.48‐cm holes and clear and red 473‐ml and clear 946‐ml plastic cups with six or ten 0.48‐ or 0.63‐cm holes. The model was successfully validated, suggesting that performance of cup traps can be predicted based on a few characteristics. The current ‘Zorro’ trap did not catch most of the flies among trap designs, but showed some advantages, including the durability and potential to recycle the plastic, small size, commercial availability and its greater selectivity for D. suzukii than the other traps tested.     

A comparison of Lucitraps and sticky targets for sampling the blowfly Lucilia sericata

The Lucitrap (Miazma Pty Ltd, Queensland, Australia) combined with a synthetic odour bait, Lucilure (Miazma Pty Ltd, Queensland, Australia), is a commercially available trap for sampling and control of Lucilia cuprina (Wiedemann) in Australia. It was tested in Hungary against Lucilia sericata (Meigen) (Diptera: Calliphoridae), a cause of sheep strike throughout temperate Europe. The standard Lucitrap was tested against black or yellow sticky target traps. Both trap types were baited with either Lucilure or liver and 10% w/v sodium sulphide solution. With Lucilure as bait, L. sericata were caught on sticky traps but not in Lucitraps. With liver and sodium sulphide as bait, sticky traps caught 500-1500 times more L. sericata than Lucitraps. An adhesive sheet fitted to the top of a Lucitrap captured 30-300 times more L. sericata then were captured inside an unaltered Lucitrap. Direct observation of metallic green calliphorids (92.1% L. sericata) alighting on Lucitraps indicated that most flies stayed for a short while (modal class 2-4 s) and only a few stayed longer, to an observed maximum of 28 s. Flies explored a mean of 1.5 entry holes (range 0-7) during a visit but only 6% entered the trap. Size of L. sericata was not a physical barrier to Lucitrap entry, because many larger species were captured. However, L. sericata captured inside Lucitraps were significantly smaller than those captured on sticky traps, demonstrating that size was of behavioural importance. The data demonstrate that the Lucitrap is not effective as a trap for L. sericata in Hungary, due mainly to a failure of flies to enter the trap in large numbers. In Australia and South Africa, L. sericata is commonly caught in Lucitraps baited with Lucilure, although L. cuprina is more numerous. Our study highlights the potential for diversity of fly behaviour between different geographical populations of the same species. Such diversity can have a significant effect on the functioning of systems for fly sampling and control, when these systems depend for their success on certain behavioural responses of the target species.     

Monitoring gene flow from transgenic sugar beet using cytoplasmic male-sterile bait plants

One of the most discussed environmental effects associated with the use of transgenic plants is the flow of genes to plants in the environment. The flow of genes may occur through pollen since it is the reproductive system that is designed for gene movement. Pollen-mediated gene escape is hard to control in mating plants. Pollen from a wind pollinator can move over distances of more than 1000 m. To investigate the efficiency of transgenic pollen movement under realistic environmental conditions, the use of bait plants might be an effective tool. In this study, cytoplasmic male-sterile (CMS) sugar beets were tested with regard to their potential for monitoring transgene flow. As the pollen source, transgenic sugar beets were used that express recombinant DNA encoding viral (beet necrotic yellow vein virus) resistance, and antibiotic (kanamycin) and herbicide (glufosinate) tolerance genes. In a field trial, the effectiveness of a hemp (Cannabis sativa) stripe containment strategy was tested by measuring the frequency of pollinated CMS bait plants placed at different distances and directions from a transgenic pollen source. The results demonstrated the ineffectiveness of the containment strategy. Physiological and molecular tests confirmed the escape and production of transgenic offspring more than 200 m behind the hemp containment. Since absolute containment is unlikely to be effective, the CMS-bait plant detection system is a useful tool for other monitoring purposes.     

Changes in serum copper level during detoxification of acutely poisoned drug addicts

Although it is known that drug addicts are a high-risk group for disruption of many homeostatic processes, little is know about changes in serum trace elements concentrations after taking the psychoactive substances. The aim of the study was to check the influence of the taking homemade heroin on serum level of copper. Blood samples were taken from 30 opiate addicts, and copper concentrations were measured by the means of atomic absorption spectrophotometry. The result of the study show that in the examined group, copper serum concentrations (1.35 mg/L) upon admission to the clinic were higher than in the control group (1.11 mg/L) but decreased during hospitalization (1.18 mg/L). There was no correlation between duration of stay at the hospital and changes in serum copper concentration.