Effects of different concentrations of GF-120 NF Naturalyte Fruit Fly Bait on attraction and feeding responses, mortality, and control of the western cherry fruit fly, Rhagoletis indifferens Curran, were determined. In the laboratory, flies that had been exposed to sugar and yeast extract and then deprived of all food for 16-20 h were attracted to 40.0% GF-120, but not to 0.6 and 4.8% GF-120 (vol:vol). Nonstarved flies were not attracted to any concentration. Flies in the field were not attracted to 55.6% GF-120 on cherry leaves, and few flies fed on the bait. In the laboratory, males fed for shorter durations on and ingested lower amounts of 0.6% than 4.8 or 40.0% GF-120, but females fed equally on all concentrations. Spinosad in GF-120 was highly toxic to flies. Lethal concentrations50 (LC50 values) of spinosad for starved flies at 1-4 d were 1.5-0.7 ppm. When gravid flies were exposed to cherries treated with 0.6, 4.8, and 40.0% GF-120, mortality was greater at each higher concentration, but none prevented oviposition. Field spray tests comparing 0.6, 4.8, and 40.0% GF-120 in 225 ml of spray per cherry tree resulted in 79-94% lower larval infestations than in controls, but no differences were seen among the concentrations. Evidence from this study indicates that fresh 40.0% GF-120 was attractive in the laboratory but that flies were not attracted to fresh GF-120 from far distances within trees, suggesting that suppression of populations is caused in large part by flies finding the bait through normal movement over large areas.
Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) is a quarantine pest of apple (Malus sp.) in Washington state that is almost identical morphologically to Rhagoletis zephyria Snow, a nonpest of apple. Historically, the longer ovipositor in R. pomonella has been used to separate it from R. zephyria, despite overlap in ovipositor lengths. Here, the objectives were to determine whether use of multiple body measurements and wing shape can improve discrimination of the species. Ovipositor lengths allowed 94.6% correct identification of female R. pomonella but only 7.0% correct identification of R. zephyria. We found that multiple body measurements and wing shape can better separate these species. Canonical variates analysis (CVA) of nine body measurements in female flies largely separated the species. In contrast, CVA of nine body measurements poorly separated the males of these species. Discriminant analysis using nine body measurements classified female R. pomonella and R. zephyria with 95.4 and 100% accuracy, respectively. Geometric morphometrics and CVA separated wing shapes between species in both sexes. Bookstein shape coordinates indicated that the wing of R. pomonella is more tapered at the tip than that of R. zephyria. Use of wing shape in an assignments test identified female R. pomonella with 98.5% and female R. zephyria with 99.0% accuracy, and it correctly identified 100% of flies whose identities were questionable based on ovipositor lengths. Results indicate that use of multiple body measurements or wing shape is an improvement over the use of ovipositor length alone for identifying female R. pomonella and R. zephyria in Washington state.
Rhagoletis pomonella (Walsh) and Rhagoletis zephyria Snow (Diptera: Tephritidae) both occur in the U.S. Pacific Northwest and are frequently confused with one another due to their morphological similarity. The apple maggot, R. pomonella, is a threat to commercial apples [Malus domestica (Borkh.) Borkh.] in the Pacific Northwest, whereas R. zephyria attacks snowberry (Symphoricarpos Dill. ex Juss) and is not considered a threat. Configuration of the surstyli in males is used to discriminate between species, but this character shows overlap. In this study, we reexamined surstyli configurations in the two species. We then used geometric morphometrics to test the hypotheses that shapes of surstyli and of aculei between the two species differ and that combining aculeus shape and size measures improves discrimination. We found that all R. pomonella had an inwardly curved surstyli configuration (based on a ratio of width across bases of prensisetae to width between the outer edges of the surstyli near their ends), whereas R. zephyria included specimens having either a parallel or divergent configuration. Using canonical variates analysis, multivariate analysis of variance, and an assignments test, we found that surstylus shape classified 99.8% of males correctly to species. Aculeus shape accurately classified 85.3% of females to species. Combining aculeus shape and length increased classification accuracy to 94.5%. Within species, surstylus and aculeus shape did not discriminate among fly populations from different host fruit, collection areas, or both. Use of surstylus shape would benefit regulatory agencies that depend on accurate identifications of R. pomonella for quarantine and management measures.
In flight tunnel tests, the percentages of oriented upwind flights of male codling moths culminating in contacting a source of different compositions of female sex pheromone gland components were determined over a dosage range of 0.1-100,000Μg. The following compositions were tested: (1) (E,E)-8,10-dodecadien-1-ol of 99.7% isomeric purity; (2) 1 + dodecanl-ol + tetradecan-1-ol; (3) 2 + decan-1-ol + (E)-9-dodecen-1-ol; and (4) an equilibrium mixture of 8,10-dodecadien-1-ol isomers (61%EE, 5%ZZ, 14%ZE, and 20%EZ). The ratios of the components in compositions 2 and 3 were chosen to produce vapor ratios equal to the natural ratios found in the female effluvium by Arn and coworkers. As the dose of composition 1 was increased from 0.1 to 10Μg, response increased from 0 to about 80% and then was approximately constant from 10 to 300Μg. Over the range 0.1-300Μg, the percentage of males contacting the septum was virtually the same as the percentage flying upwind. From 300 to 100,000Μg, the percentage of males flying upwind and contacting the source steadily decreased from about 80 to 0%. The male responses to compositions 2 and 3 were virtually identical to the response to 1. These results indicate, contrary to published reports, that dodecan-1-ol and tetradecan-1-ol in combination with 1 do not increase the responses of the behavioral modes determining degree of attractancy and disruption of sexual communication over that of 1 alone. These results also show that decan-1-ol and (E)-9-dodecen-1-ol do not enhance response in the five-component mixture. The response to composition 4 increased from 0% at a dose of 0.3Μg to 26% at a dose of 30Μg and then decreased to 0% at a dose of 3000Μg. Thus, the inhibiting effect of the isomers on response was greater at the higher doses.
The existing standardised test systems for assessing the toxicity of crop protection products to the non‐target arthropods Typhlodromus pyri (Acari: Phytoseiidae) and Aphidius rhopalosiphi (Hymenoptera: Aphidiidae) are limit tests designed to compare a single‐use rate of the product with a water control. The suitability of these test systems for generating dose‐response data as required for refined ecotoxicological risk assessment was evaluated. Data on dose‐response toxicity of crop protection products to T. pyri and A. rhopalosiphi were generated under worst‐case laboratory and to T. pyri under extended laboratory conditions and analysed using the standard Probit method, a logistic regression, a generalised Probit analysis, and the moving average‐angle method in order to calculate the LR50‐values (application rate killing 50 % of the exposed organisms). The fit of the models, the precision of the resulting LR50 values, and the required minimum number of replicates were compared. In 85 % of the studies, at least one of the statistical methods led to satisfactory results. The moving average‐angle method was the most widely applicable method. The results show that the existing guidelines can be used to perform dose‐response tests. Implications for risk assessment are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.