Occurrence of the Tamarix Leafhopper, Opsius stactogalus Fieber (Hemiptera: Cicadellidae), in Argentina

The paleartic tamarix leafhopper, Opsius stactogalus Fieber (Hemiptera: Cicadellidae), can reduce the growth of tamarisk due to the aggregate feeding imposed by their populations. The species was mentioned for Argentina in Metcalf's catalogue (1967) without locality or region reference, and the contributions on Cicadellidae published by many authors after Metcalf omitted this distributional data. Populations of O. stactogalus on Tamarix sp. were found in 12 sites between 28° 48′ to 39° 17′ S and 64° 06′ to 70° 04′ W, located in both the Neotropical and Andean biogeographic regions

Coenzyme A-transferase-independent butyrate re-assimilation in Clostridium acetobutylicum - evidence from a mathematical model

The hetero-dimeric CoA-transferase CtfA/B is believed to be crucial for the metabolic transition from acidogenesis to solventogenesis in Clostridium acetobutylicum as part of the industrial-relevant acetone-butanol-ethanol (ABE) fermentation. Here, the enzyme is assumed to mediate re-assimilation of acetate and butyrate during a pH-induced metabolic shift and to faciliate the first step of acetone formation from acetoacetyl-CoA. However, recent investigations using phosphate-limited continuous cultures have questioned this common dogma. To address the emerging experimental discrepancies, we investigated the mutant strain Cac-ctfA398s::CT using chemostat cultures. As a consequence of this mutation, the cells are unable to express functional ctfA and are thus lacking CoA-transferase activity. A mathematical model of the pH-induced metabolic shift, which was recently developed for the wild type, is used to analyse the observed behaviour of the mutant strain with a focus on re-assimilation activities for the two produced acids. Our theoretical analysis reveals that the ctfA mutant still re-assimilates butyrate, but not acetate. Based upon this finding, we conclude that C. acetobutylicum possesses a CoA-tranferase-independent butyrate uptake mechanism that is activated by decreasing pH levels. Furthermore, we observe that butanol formation is not inhibited under our experimental conditions, as suggested by previous batch culture experiments. In concordance with recent batch experiments, acetone formation is abolished in chemostat cultures using the ctfa mutant

Factors influencing citrus fruit scarring caused by Pezothrips kellyanus

[EN] Kelly s citrus thrips (KCT) Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae) is a recently recorded cosmopolitan citrus pest, causing fruit scarring that results in downgrading of fruit. Due to the detrimental effects caused on fruits by KCT, we wanted to study some of the factors influencing fruit scarring. Specifically, the objectives were: (1) to determine the fruit development stage when citrus fruits are damaged by KCT and the population structure of KCT during this period, (2) to study the influence of temperature on intensity of damage, and finally, (3) to identify alternative host plants. KCT populations on flowers and fruitlets and alternate plant hosts were sampled in four citrus orchards from 2008 to 2010. The percentage of damaged fruits was also recorded. The exotic vine Araujia sericifera (Apocynaceae) was recorded as a new host for KCT. Thrips scarring started to increase at 350 650 degree-days (DD) above 10.2 C, coinciding with a peak abundance of the second instar larval stages over all 3 years of the study. The maximum percentage of larval stages of KCT was observed in the 3 years at about 500 DD, a period which corresponds to the end of May or early June. Variation in the severity of fruit scarring appeared to be related to air temperature. Temperature likely affects the synchronisation between the peak in abundance of KCT larvae, and the period when fruitlets are susceptible to thrips damage. Temperature can also influence the survival and development of KCT populations in citrus and other host plants in the citrus agro-ecosystem.The authors thank Alejandro Tena for his valuable suggestions and two anonymous referees for their careful review and helpful comments. We also extend our thanks to the owners of the commercial orchards for giving us permission to use their citrus orchards. The first author was awarded an FPI fellowship from the Polytechnic University of Valencia to obtain her PhD degree.Navarro Campos, C.; Pekas, A.; Aguilar Martí, MA.; Garcia Marí, F. (2013). Factors influencing citrus fruit scarring caused by Pezothrips kellyanus. Journal of Pest Science. (86):459-467. doi:10.1007/s10340-013-0489-7S45946786Baker GJ (2006) Kelly citrus thrips management. Fact sheet. Government of South Australia, primary industries and resources SA. http://www.sardi.sa.gov.au/__data/assets/pdf_file/0010/44875/kctfact_sheet.pdf . Accessed 16 July 2012Baker GJ, Jackman DJ, Keller M, MacGregor A, Purvis S (2002) Development of an integrated pest management system for thrips in Citrus. HAL Final Report CT97007. http://www.sardi.sa.gov.au/pestsdiseases/horticulture/horticultural_pests/kelly_citrus_thrips/research_report_1997-2000 . Accessed 16 July 2012Bedford ECG (1998) Thrips, wind and other blemishes. Citrus pests in the Republic of South Africa. In: Bedford ECG, van den Berg MA, de Villiers EA (eds) ARC-Institute for tropical and subtropical crops, Nelspruit, South Africa, pp 170–183Blank RH, Gill GSC (1997) Thrips (Thysanoptera: Terebrantia) on flowers and fruit of citrus in New Zealand. N Z J Crop Hortic Sci 25:319–332Chellemi D, Funderburk F, Hall D (1994) Seasonal abundance of flower-inhabiting Frankliniella species (Thysanoptera: Thripidae) on wild plant species. Environ Entomol 23:337–342Conti F, Tuminelli R, Amico C, Fisicaro R, Frittitta C, Perrotta G, Marullo R (2001) Monitoring Pezothrips kellyanus on citrus in eastern Sicily, Thrips and tospoviruses. In: Proceedings of the 7th international symposium on Thysanoptera, Reggio Calabria, 1–8 July 2001, Italy, pp 207–210Costa L, Mateus C, zurStrassen R, Franco JC (2006) Thrips (Thysanoptera) associated to lemon orchards in the Oeste region of Portugal. IOBC/WPRS Bull 29:285–291European Plant Protection Organisation Reporting Service [EPPO] (2006) Pezothrips kellyanus. http://www.eppo.org/QUARANTINE/Pest_Risk_Analysis/PRAdocs_insects/06-12760%20DS%20PEZTKE.doc. Accessed 18 June 2012European Plant ProtectionOrganisation Reporting Service [EPPO] (2005) Scirtothrips aurantii, Scirtothrips citri, Scirtothrips dorsalis. EPPO Bull 35:353–356Franco JC, Garcia-Marí F, Ramos AP, Besri M (2006) Survey on the situation of citrus pest management in Mediterranean countries. IOBC/WPRS Bull 29:335–346Froud KJ, Stevens PS, Steven D (2001) Survey of alternative host plants for Kelly’s citrus thrips (Pezothrips kellyanus) in citrus growing regions. N Z Plant Prot 54:15–20Gomez-Clemente F (1952) Un tisanóptero causante de daños en las naranjas de algunas zonas de Levante. Boletín de Patología Vegetal y Entomología Agrícola 19:135–146Grout TG, Morse JG, O’Connell NV, Flaherty DL, Goodell PB, Freeman MW, Coviello RL (1986) Citrus thrips (Thysanoptera: Thripidae) phenology and sampling in the San Joaquin Valley. J Econ Entomol 79:1516–1523Horton J (1918) The citrus thrips. US Dep Agric Bull 616:1–42Kirk WDJ (1987) A key to the larvae of some common Australian flower thrips (Insecta: Thysanoptera), with a host-plant survey. Aust J Zool 35:173–185Lacasa A, Llorens JM, Sánchez JA (1996) Un Scirtothrips (Thysanoptera: Thripidae) causa daños en los cítricos en España. Bol San Veg Plagas 22:79–95Lewis HC (1935) Factors influencing citrus thrips damage. J Econ Entomol 28:1011–1015Lewis T (1997) Distribution, abundance and population dynamics. In: Lewis T (ed) Thrips as crop pests. CAB International, Wallingford, pp 217–258Lovatt C, Streeter S, Minter T, O’connell N, Flaherty D, Freeman M, Goodell P (1984) Phenology of flowering in Citrus sinensis (L.) Osbeck, cv. Washington navel orange. Proc Int Soc Citric 1:186–190Marullo R (1998) Pezothrips kellyanus, un nuovo tripide parassita delle colture meridionali. Informatore Fitopatologico 48:72–75Milne JR, Milne M, Walter GH (1997) A key to larval thrips (Thysanoptera) from Granite Belt stonefruit trees and a first description of Pseudanaphothrips achaetus (Bagnall) larvae. Aust J Entomol 36:319–326Mound LA, Jackman DJ (1998) Thrips in the economy and ecology of Australia, In: Zalucki MP, RAI Drew RAI, White GG (eds) Pest Management: future challenges, Proceedings of the sixth Australian applied entomological research conference, University of Queensland, St. Lucia, pp 472–478Mound LA, Marullo R (1996) The thrips of Central and South America (Insecta: Thysanoptera): an introduction. Mem Entomol Int 6:1–487Mound LA, Walker AK (1982) Terebrantia (Insecta: Thysanoptera). 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Environ Entomol 15:763–76

Mathematical modelling of clostridial acetone-butanol-ethanol fermentation

Clostridial acetone-butanol-ethanol (ABE) fermentation features a remarkable shift in the cellular metabolic activity from acid formation, acidogenesis, to the production of industrial-relevant solvents, solventogensis. In recent decades, mathematical models have been employed to elucidate the complex interlinked regulation and conditions that determine these two distinct metabolic states and govern the transition between them. In this review, we discuss these models with a focus on the mechanisms controlling intra- and extracellular changes between acidogenesis and solventogenesis. In particular, we critically evaluate underlying model assumptions and predictions in the light of current experimental knowledge. Towards this end, we briefly introduce key ideas and assumptions applied in the discussed modelling approaches, but waive a comprehensive mathematical presentation. We distinguish between structural and dynamical models, which will be discussed in their chronological order to illustrate how new biological information facilitates the ‘evolution’ of mathematical models. Mathematical models and their analysis have significantly contributed to our knowledge of ABE fermentation and the underlying regulatory network which spans all levels of biological organization. However, the ties between the different levels of cellular regulation are not well understood. Furthermore, contradictory experimental and theoretical results challenge our current notion of ABE metabolic network structure. Thus, clostridial ABE fermentation still poses theoretical as well as experimental challenges which are best approached in close collaboration between modellers and experimentalists

Inverse density-dependent parasitism of Opsius stactogalus Fieber (Homoptera: Cicadellidae) by Gonatopus sp. (Hymenoptera: Dryinidae)

Volume: 77Start Page: 61End Page: 6

Hesperopsis graciliae (MacNeill) (Lepidoptera: Hesperiidae) flight between hostplants and Prosopis glandulosa Torrey

Volume: 73Start Page: 186End Page: 18

High seasonal rainfall precedes Oliarces clara Banks (Neuroptera: Ithonidae) spring emergence

Volume: 74Start Page: 217End Page: 22

Avoidance of direct sunlight by adult Hesperopsis gracielae (Macneill) (Lepidoptera: Hesperiidae)

Volume: 74Start Page: 157End Page: 16