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Michael W. Gates - One of the best experts on this subject based on the ideXlab platform.
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use of flowering plants to enhance parasitism and predation rates on two Squash bug species anasa tristis and anasa armigera hemiptera coreidae
Insects, 2019Co-Authors: Mary L. Cornelius, Bryan T Vinyard, Michael W. GatesAbstract:A two-year study evaluated the effect of a flowering border of buckwheat Fagopyrum esculentum Moench on rates of egg parasitism, egg predation and adult parasitism on two Squash bug species, Anasa tristis (DeGeer) and Anasa armigera Say, by comparing rates in Squash fields with and without a flowering border. Furthermore, we evaluated whether there was an edge effect by comparing parasitism and predation rates in plots located in the corner of a Squash field with plots located in the center of a Squash field for fields with and without a flowering border. The egg parasitism rates were not affected by either treatment (flowering border or control) or plot location (edge or center). Anasa armigera egg masses only accounted for 4.3% of the total egg masses collected. The egg parasitism rates increased gradually throughout the season, peaking in the last week of August in 2017 at 45% for A. tristis egg masses. The most common egg parasitoid recovered was Gryon pennsylvanicum (Ashmead) followed by Ooencyrtus anasae (Ashmead). Adult parasitism was not affected by treatment, but A. tristis adult parasitism rates were higher in plots located on the edge of Squash fields compared with plots located in the center of Squash fields in 2016. Since adult parasitoid, Trichopoda pennipes (Fabricius) flies were observed visiting buckwheat flowers, future studies could explore the possibility that the flowering buckwheat may have a more impact on adult parasitism if there was a greater distance between fields with and without a flowering border.
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impact of the egg parasitoid gryon pennsylvanicum hymenoptera scelionidae on sentinel and wild egg masses of the Squash bug hemiptera coreidae in maryland
Environmental Entomology, 2016Co-Authors: Mary L. Cornelius, Matthew L. Buffington, Elijah J. Talamas, Michael W. GatesAbstract:Seasonal changes in egg parasitism and predation rates on sentinel (laboratory-reared) and wild (naturally occurring) egg masses of the Squash bug, Anasa tristis (De Geer), were evaluated in Squash fields in Maryland from June through September in 2013 and 2014. Rates of egg parasitism were significantly higher on wild egg masses than on sentinel egg masses. Squash bug nymphal emergence was significantly higher on sentinel egg masses than on wild egg masses. Between the first week of July and the first week of September of both survey years, Squash bug nymphs emerged from 24.2% of wild eggs compared with 46.2% of sentinel eggs and parasitoids emerged from 55.7% of wild eggs compared with only 21.8% of sentinel eggs. Sentinel egg masses significantly underestimated the rate of natural egg parasitism. The egg parasitoid, Gryon pennsylvanicum (Ashmead), was responsible for over 99% of parasitism of Squash bug eggs. There was a significant negative correlation between parasitoid emergence and nymphal emergence, suggesting that parasitoids were able to suppress Squash bug populations. The average rate of parasitoid emergence peaked on wild egg masses on the fifth week of July at 72.8%, whereas the average rate of nymphal emergence from wild egg masses was <20% from the fifth week of July until the first week of September. These results demonstrate that G. pennsylvanicum was able to efficiently track wild Squash bug eggs throughout the season and that it has the potential to be an effective biological control agent of the Squash bug in Maryland.
Mary L. Cornelius - One of the best experts on this subject based on the ideXlab platform.
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use of flowering plants to enhance parasitism and predation rates on two Squash bug species anasa tristis and anasa armigera hemiptera coreidae
Insects, 2019Co-Authors: Mary L. Cornelius, Bryan T Vinyard, Michael W. GatesAbstract:A two-year study evaluated the effect of a flowering border of buckwheat Fagopyrum esculentum Moench on rates of egg parasitism, egg predation and adult parasitism on two Squash bug species, Anasa tristis (DeGeer) and Anasa armigera Say, by comparing rates in Squash fields with and without a flowering border. Furthermore, we evaluated whether there was an edge effect by comparing parasitism and predation rates in plots located in the corner of a Squash field with plots located in the center of a Squash field for fields with and without a flowering border. The egg parasitism rates were not affected by either treatment (flowering border or control) or plot location (edge or center). Anasa armigera egg masses only accounted for 4.3% of the total egg masses collected. The egg parasitism rates increased gradually throughout the season, peaking in the last week of August in 2017 at 45% for A. tristis egg masses. The most common egg parasitoid recovered was Gryon pennsylvanicum (Ashmead) followed by Ooencyrtus anasae (Ashmead). Adult parasitism was not affected by treatment, but A. tristis adult parasitism rates were higher in plots located on the edge of Squash fields compared with plots located in the center of Squash fields in 2016. Since adult parasitoid, Trichopoda pennipes (Fabricius) flies were observed visiting buckwheat flowers, future studies could explore the possibility that the flowering buckwheat may have a more impact on adult parasitism if there was a greater distance between fields with and without a flowering border.
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comparative study of egg parasitism by gryon pennsylvanicum hymenoptera scelionidae on two Squash bug species anasa tristis and anasa armigera hemiptera coreidae
Environmental Entomology, 2018Co-Authors: Mary L. Cornelius, Bryan T VinyardAbstract:This study evaluated how the size of the egg mass and the parasitoids prior exposure to eggs influenced parasitism rates by Gryon pennsylvanicum Ashmead (Hymenoptera: Scelionidae) on egg masses of two Squash bug species, Anasa tristis DeGeer and Anasa armigera Say (Hemiptera: Coreidae). G. pennsylvanicum is the primary egg parasitoid of A. tristis. There were no published reports available on egg parasitism of A. armigera. In choice tests, there was no difference in host acceptance by G. pennsylvanicum of egg masses of the two Squash bug species. In no-choice tests, overall parasitism rates were significantly higher on A. armigera egg masses than on A. tristis egg masses. Naive parasitoids had significantly higher parasitism rates than experienced parasitoids on egg masses of both Squash bug species. In a comparison of parasitism rates of field-collected and laboratory-tested A. tristis egg masses of different sizes, parasitism rates were similar in the field and in the laboratory, with the exception of egg masses with > 25 eggs. Only 17.9% of eggs were parasitized in the laboratory, compared with 36.4% in the field. Results of this study indicate that transient egg limitation prevents G. pennsylvanicum from ovipositing in every available host egg in large Squash bug egg masses. The low parasitism rate of G. pennsylvanicum on large egg masses may limit its effectiveness as a biological control agent of Squash bugs.
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impact of the egg parasitoid gryon pennsylvanicum hymenoptera scelionidae on sentinel and wild egg masses of the Squash bug hemiptera coreidae in maryland
Environmental Entomology, 2016Co-Authors: Mary L. Cornelius, Matthew L. Buffington, Elijah J. Talamas, Michael W. GatesAbstract:Seasonal changes in egg parasitism and predation rates on sentinel (laboratory-reared) and wild (naturally occurring) egg masses of the Squash bug, Anasa tristis (De Geer), were evaluated in Squash fields in Maryland from June through September in 2013 and 2014. Rates of egg parasitism were significantly higher on wild egg masses than on sentinel egg masses. Squash bug nymphal emergence was significantly higher on sentinel egg masses than on wild egg masses. Between the first week of July and the first week of September of both survey years, Squash bug nymphs emerged from 24.2% of wild eggs compared with 46.2% of sentinel eggs and parasitoids emerged from 55.7% of wild eggs compared with only 21.8% of sentinel eggs. Sentinel egg masses significantly underestimated the rate of natural egg parasitism. The egg parasitoid, Gryon pennsylvanicum (Ashmead), was responsible for over 99% of parasitism of Squash bug eggs. There was a significant negative correlation between parasitoid emergence and nymphal emergence, suggesting that parasitoids were able to suppress Squash bug populations. The average rate of parasitoid emergence peaked on wild egg masses on the fifth week of July at 72.8%, whereas the average rate of nymphal emergence from wild egg masses was <20% from the fifth week of July until the first week of September. These results demonstrate that G. pennsylvanicum was able to efficiently track wild Squash bug eggs throughout the season and that it has the potential to be an effective biological control agent of the Squash bug in Maryland.
Peter Palukaitis - One of the best experts on this subject based on the ideXlab platform.
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the rate of cell to cell movement in Squash of cucumber mosaic virus is affected by sequences of the capsid protein
Molecular Plant-microbe Interactions, 1999Co-Authors: Sekman Wong, Sharon Sweechin Thio, Michael H Shintaku, Peter PalukaitisAbstract:The M strain of cucumber mosaic virus (CMV) does not infect Squash plants systemically and moves very slowly in inoculated cotyledons. Systemic infection and an increase in the rate of local movement were observed when amino acids 129 or 214 of the M-CMV capsid protein (CP) were altered to those present in the Fny strain of CMV. While the opposite alterations to the CP of Fny-CMV inhibited systemic infection of Squash, they did not show the same effects on the rates of both cell-to-cell and long-distance movement. However, the ability of CMV to infect Squash systemically was affected by the rate of cell-to-cell movement.
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differential effects of satellite rna on the accumulation of cucumber mosaic virus rnas and their encoded proteins in tobacco vs zucchini Squash with two strains of cmv helper virus
Virology, 1995Co-Authors: Amit Galon, Peter Palukaitis, I B KaplanAbstract:Abstract The presence of cucumber mosaic virus (CMV) satellite RNA usually reduces the yield of accumulated helper virus, although more so in solanaceous than in cucurbit hosts. The accumulation of viral RNA and viral-encoded proteins of two strains of CMV (Fny- and Sny-) known to differ in their ability to support satellite RNA in zucchini Squash was examined in Squash and tobacco to determine the effect of satellite RNA on the accumulation of viral-associated components. In the absence of satellite RNA, Fny- and Sny-CMV showed similar levels of accumulation of RNA at 7 days postinoculation (p.i.), but by 14 days p.i, the Fny-CMV RNAs accumulated to lower levels than did both strains at 7 days p.i., in either host. The levels of accumulated Sny-CMV-encoded proteins were higher than those encoded by Fny-CMV in tobacco, but not Squash plants, at 7 days p.i. At 14 days p.i., for Fny-CMV vs Sny-CMV, there were differences in the levels of accumulation of most CMV-encoded proteins in both hosts, more exacerbated in tobacco vs Squash. The effect of satellite RNA was to intensify these differences; that is, by 7 days p.i., satellite RNA reduced the accumulation of Fny-CMV RNAs 1 and 2 and their encoded proteins in both tobacco and Squash but had little or no effect on the accumulation of Sny-CMV RNAs or encoded proteins. By 14 days p.i., the levels of accumulation of all Fny-CMV RNAs and encoded proteins were severely reduced in both hosts, and the levels of accumulation of Sny-CMV RNAs 1 and 2 and their encoded proteins were also reduced in tobacco, but not Squash, Sny-CMV did not support satellite RNA accumulation in Squash plants or protoplasts. Satellite RNA did not appear to have a direct effect on the movement of either CMV strain. Rather, accumulation studies in tobacco protoplasts indicated that the difference in response of Fny-CMV vs Sny-CMV to satellite RNA in tobacco was due to the extent to which satellite RNA affected the levels of RNA 1, and to a lesser extent RNA 2, and their encoded proteins, 1a and 2a, both components of the CMV replicase.
Bryan T Vinyard - One of the best experts on this subject based on the ideXlab platform.
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use of flowering plants to enhance parasitism and predation rates on two Squash bug species anasa tristis and anasa armigera hemiptera coreidae
Insects, 2019Co-Authors: Mary L. Cornelius, Bryan T Vinyard, Michael W. GatesAbstract:A two-year study evaluated the effect of a flowering border of buckwheat Fagopyrum esculentum Moench on rates of egg parasitism, egg predation and adult parasitism on two Squash bug species, Anasa tristis (DeGeer) and Anasa armigera Say, by comparing rates in Squash fields with and without a flowering border. Furthermore, we evaluated whether there was an edge effect by comparing parasitism and predation rates in plots located in the corner of a Squash field with plots located in the center of a Squash field for fields with and without a flowering border. The egg parasitism rates were not affected by either treatment (flowering border or control) or plot location (edge or center). Anasa armigera egg masses only accounted for 4.3% of the total egg masses collected. The egg parasitism rates increased gradually throughout the season, peaking in the last week of August in 2017 at 45% for A. tristis egg masses. The most common egg parasitoid recovered was Gryon pennsylvanicum (Ashmead) followed by Ooencyrtus anasae (Ashmead). Adult parasitism was not affected by treatment, but A. tristis adult parasitism rates were higher in plots located on the edge of Squash fields compared with plots located in the center of Squash fields in 2016. Since adult parasitoid, Trichopoda pennipes (Fabricius) flies were observed visiting buckwheat flowers, future studies could explore the possibility that the flowering buckwheat may have a more impact on adult parasitism if there was a greater distance between fields with and without a flowering border.
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comparative study of egg parasitism by gryon pennsylvanicum hymenoptera scelionidae on two Squash bug species anasa tristis and anasa armigera hemiptera coreidae
Environmental Entomology, 2018Co-Authors: Mary L. Cornelius, Bryan T VinyardAbstract:This study evaluated how the size of the egg mass and the parasitoids prior exposure to eggs influenced parasitism rates by Gryon pennsylvanicum Ashmead (Hymenoptera: Scelionidae) on egg masses of two Squash bug species, Anasa tristis DeGeer and Anasa armigera Say (Hemiptera: Coreidae). G. pennsylvanicum is the primary egg parasitoid of A. tristis. There were no published reports available on egg parasitism of A. armigera. In choice tests, there was no difference in host acceptance by G. pennsylvanicum of egg masses of the two Squash bug species. In no-choice tests, overall parasitism rates were significantly higher on A. armigera egg masses than on A. tristis egg masses. Naive parasitoids had significantly higher parasitism rates than experienced parasitoids on egg masses of both Squash bug species. In a comparison of parasitism rates of field-collected and laboratory-tested A. tristis egg masses of different sizes, parasitism rates were similar in the field and in the laboratory, with the exception of egg masses with > 25 eggs. Only 17.9% of eggs were parasitized in the laboratory, compared with 36.4% in the field. Results of this study indicate that transient egg limitation prevents G. pennsylvanicum from ovipositing in every available host egg in large Squash bug egg masses. The low parasitism rate of G. pennsylvanicum on large egg masses may limit its effectiveness as a biological control agent of Squash bugs.
Chien Y. Wang - One of the best experts on this subject based on the ideXlab platform.
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transcript levels of antioxidative genes and oxygen radical scavenging enzyme activities in chilled zucchini Squash in response to superatmospheric oxygen
Postharvest Biology and Technology, 2008Co-Authors: Raymond W M Fung, Yonghua Zheng, Shiow Y Wang, Chien Y. WangAbstract:The transcript levels of antioxidative genes including Mn-superoxide dismutase (Mn-SOD), Cu/Zn SOD, ascorbate peroxidise (APX), and catalase (CAT) were relatively constant during storage at 5 °C with high oxygen treatment in freshly harvested zucchini Squash (Cucurbita pepo L. cv. Elite). However, the expressions of alternative oxidase (AOX) were induced slightly in Squash treated with 60% and 100% oxygen for 3 days when compared with control Squash. These increases in AOX transcript levels were correlated with the increased chilling resistance in the treated Squash. The corresponding oxygen radical scavenging enzyme activities including SOD, APX, CAT, and peroxidise (POD) in treated samples were also higher than those in the control for the first 3 days at 5 °C. Transcript levels of AOX increased substantially between 3 and 6 days in all treatments suggesting the involvement of alternative respiratory pathway during chilling stress. All of the enzyme activities in 100% oxygen treated Squash started to decline after 6 or 9 days of cold storage to a level comparable or lower than those of the control. These declines were correlated to the loss of chilling resistance in the 100% oxygen treated tissue as indicated in the chilling injury index. However, Squash treated with 60% oxygen maintained elevated levels of all enzyme activities except POD and sustained the least chilling injury throughout the 15 days of storage at 5 °C. The oxygen radical absorbance capacity (ORAC) values and total phenol content remained high in Squash treated with 60% and 100% oxygen for the first 9 days, then their levels in the 100% oxygen treated samples declined sharply while those in the 60% oxygen treated samples maintained elevated, indicating that both ORAC activity and phenolic content may also contribute to the resistance of tissue against chilling injury. The 100% oxygen treated Squash showed the lowest respiration rate and 60% oxygen treated samples had the lowest ethylene production. These data may also be an indication of the low chilling injury in the high oxygen treated Squash.
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Effect of temperature preconditioning on catalase, peroxidase, and superoxide dismutase in chilled zucchini Squash
Postharvest Biology and Technology, 1995Co-Authors: Chien Y. WangAbstract:Abstract The development of chilling injury symptoms in zucchini Squash (Cucurbita pepo L., cv. ‘Elite’) stored at 5 °C was delayed by preconditioning the fruit at a temperature of 15 °C for two days. This temperature preconditioning treatment suppressed the increase in peroxidase activity and reduced the decline of catalase activity in Squash during subsequent storage at 5 °C. The superoxide dismutase activity remained higher in temperature-conditioned Squash than in untreated Squash throughout storage. These results indicate that acclimation to chilling temperature in Squash may also involve modifications in the activities of catalase, peroxidase, and superoxide dismutase.
