Componentes químicos associados à resistência de Lycopersicon hirsutum f. typicum a Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

Este trabalho foi conduzido em casa de vegetação no Campus da Universidade Federal de Viçosa, Minas Gerais, Brasil de maio a setembro de 1997 e objetivou estudar a resistência do acesso LA 1777 de Lycopersicon hirsutum f. typicum a Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) e os prováveis compostos químicos envolvidos na resistência. Utilizaram-se as cultivares de Santa Clara (tomate para consumo in natura) e IPA-5 (tomate industrial) de Lycopersicon esculentum como padrões de suscetibilidade à praga. Avaliaram-se os números de minas pequenas (comprimento 0,5 cm); sobrevivência, estádio de desenvolvimento do inseto, peso de pupas, proporção sexual, fertilidade de adultos e a taxa de eclosão de larvas. Foram identificados picos nas correntes de íons do extrato hexânico das folhas e as prováveis substâncias associadas a estes utilizando-se cromatógrafo a gás acoplado a espectrômetro de massa. L. hirsutum f. typicum apresentou resistência à traça do tomateiro em relação a L. esculentum, o que refletiu em menor número de minas grandes/folha e maiores duração da fase larval, mortalidade de larvas e número de minas pequenas de T. absoluta. Foram identificados 14 picos nas correntes de íons, com tempos de 10,43 (pico 1) a 26,03 min. (pico 14). Os picos 8, 9, 10 e 12 estiveram relacionados com a resistência de L. hirsutum f. typicum a T. absoluta. O pico 14 ocorreu apenas na cultivar Santa Clara e esteve associado ao aumento da suscetibilidade do tomateiro a T. absoluta. Os prováveis compostos associados ao pico oito foram os sesquiterpenos 2,5,5-trimetil-1,3,6-heptatrieno, (+) canfeno, farneseno ou santalol. As prováveis substâncias associadas ao pico nove foram os sesquiterpenos α-bergamoteno, farneseno, β-sinesal e farnesol. Não foram encontradas substâncias prováveis associadas aos picos 10, 12 e 14.This work was carried out in a greenhouse at the Universidade Federal de Viçosa "Campus", Minas Gerais, Brazil, between May and September 1997 and its objective was study the resistance of the accession LA 1777 of Lycopersicon hirsutum f. typicum to Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and the compounds possibly involved in the resistance. The varieties Santa Clara (tomato for in natura consumption) and IPA-5 (industrial tomato) of Lycopersicon esculentum were used as pest susceptibility standards. The number of small and large mines ( 0.5 cm long, respectively); survival; development stage; pupa weight; sexual proportion; fertility, and rate of larvae eclosion were assessed. Peaks of the ion current of hexane extract of tomato leaves and the possible compounds associated with them were identified using a gas chromatograph coupled to a mass spectrometer. L. hirsutum f. typicum showed resistance to the tomato leafminer in comparison with L. esculentum, what was reflected by the smaller number of large mines/ leaf and greater length of larval phase, mortality of larvae and number of small mines of T. absoluta. Fourteen peaks were identified in the total ion current with retention times ranging from 10.43 (peak 1) to 26.03 min (peak 14). The peaks 8, 9, 10 and 12 were associated with T. absoluta resistance in L. hirsutum f. typicum. The peak 14 occurred only in the variety Santa Clara with an increased tomato susceptibility to T. absoluta. The probable compounds associated with peak 8 were the sesquiterpenes 2,5,5-trimethyl-1,3,6-heptatriene, (+) camphene, farnesene or santalol. The probable substances associated with peak 9 were the sesquiterpenes α-bergamotene, farnesene, β-sinesal, or farnesol. No substance associated with peaks 10, 12 and 14 were found

Study of the doubly charmed tetraquark T+cc

Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed

Development and predatory capacity of Chrysoperla externa (Neuroptera: Chrysopidae) larvae at different temperatures.

Chrysoperla externa (Neuroptera: Chrysopidae) is one of the natural enemies of the corn leaf aphid Rhopalosiphum maidis (Hemiptera: Aphididae) and has potential application in the biological control of that pest. The effect of? temperature on the development and the predatory capacity of this chrysopid fed with R. maidis nymphs was investigated. Fresh eggs of C. externa were maintained at 15, 20, 25 or 30 °C under 70% relative humidity and 12 h photophase, and the duration of the embryonic stage, as well as the duration and viability of the larval (first, second and third instars), prepupal, pupal and adult forms of the predator were evaluated. The duration of each of these stages decreased with increasing temperature, whilst the viabilities of all forms attained 100% at 20 and 25 °C. The threshold temperature and the value of the thermal constant K obtained for the complete life cycle (egg to adult) were, respectively, 10.7 °C and 377.8 degree-days. Independent of temperature, the consumption of R. maidis nymphs by C. externa increased as the larvae reached maturity. At 20 and 25 °C the average number of aphids consumed during the complete larval stage was maximal at approximately 350 specimens. It is concluded, therefore, that the development of the immature forms of C. externa fed on R. maidis as well as its viability and predatory capacity, were favored at temperatures between 20 and 25 °C.201

AVALIAÃÃO DA SELETIVIDADE DE INSETICIDAS UTILIZADOS NA TOMATICULTURA A Trichogramma pretiosum RILEY (HYMENOPTERA: TRICHOGRAMMATIDAE)

A integração de estratégias de regulação populacional de pragas em tomateiro, por meio de Trichogramma spp. e de medidas químicas, pode reduzir os problemas ocasionados pelo uso indiscriminado de inseticidas. Neste trabalho avaliou-se o impacto dos seguintes inseticidas em g i.a. L-1 de água: lufenurom (0,4), triflumurom (0,15), imidaclopride (0,28), ciromazina (0,11), metoxifenozide (0,12), pirimicarbe (0,25) e abamectina (0,18) sobre Trichogramma pretiosum Riley, oriundos de Sete Lagoas, MG. Os bioensaios foram realizados, oferecendo-se às fêmeas do parasitóide, ovos de Anagasta kuehniella (Zeller), 1h e 24h após o tratamento. Os ovos foram imersos nas caldas químicas e em água (testemunha), e oferecidos às fêmeas por um período de 48h. Foram tomadas aleatoriamente 15 fêmeas recém-emergidas (F1) de cada tratamento, para avaliação do efeito dos inseticidas sobre essa geração. Observou-se que abamectina foi o produto mais prejudicial a T. pretiosum para todas as características biológicas avaliadas. Lufenurom foi o único composto que não reduziu significativamente a emergência de T. pretiosum, independente da geração e da época de exposição desse parasitóide aos inseticidas. Os produtos avaliados diminuíram a longevidade dos indivíduos das gerações maternal e F1. A razão sexual não foi afetada por nenhum dos compostos avaliados. Ciromazina e metoxifenozide foram os produtos menos prejudiciais a T. pretiosum. Palavras-chave: Parasitóide, tomate, produtos fitossanitários, impacto ABSTRACT The integration of population regulation strategy of pests in tomato crop through Trichogramma spp. and chemical control, can decrease the problems associated with indiscriminate use of insecticides. This work was carried out to evaluate the impact of insecticides, in grams a.i. L-1 of water: lufenuron (0.4), triflumuron (0.15), imidacloprid (0.28), cyromazine (0.11), methoxifenozide (0.12), pirimicarb (0.25) and abamectin (0.18), on a strain of Trichogramma pretiosum Riley from Sete Lagoas, MG, Brazil. Eggs of Anagasta kuehniella (Zeller) were exposed to parasitism 1 hour and 24 hours after their immersion in the chemical solutions and in water (control). The eggs were dipped for five seconds in solutions and later on they were offered to the parasitism for 48 hours. To evaluate the effects of the insecticides to parasitoids of the generation F1, 15 females were taken at random. Abamectin was the most toxic for all biological parameters of T. pretiosum. Lufenuron was the only compound that did not reduced the emergency of T. pretiosum significantly, independent of the generation and time of exposition of that parasitoids. The evaluated products reduced the longevity of individuals maternal and F1 stage. The sexual rate did not affected by none evaluated products. Cyromazine and methoxifenozide were less toxic products to T. pretiosum. Key words: Parasitoid, tomato, pesticides, impac

A Smart Irrigation Tool to Determine the Effects of ENSO on Water Requirements for Tomato Production in Mozambique

Irrigation scheduling is used by growers to determine the right amount and timing of water application. In most parts of Mozambique, 90% of the total yearly precipitation occurs from November to March. The El Niño Southern Oscillation (ENSO) phenomenon influences the climate in Mozambique and affects the water demand for crop production. The objectives of this work were to quantify the effects of ENSO phenomenon on tomato crop water requirements, and to create the AgroClimate irrigation tool (http://mz.agroclimate.org/) to assist farmers in improving irrigation management. This study was based on daily grid-based climate information from 1983 to 2016 from the Climate Forecast System Reanalysis. Daily crop evapotranspiration was calculated by Hargreaves equation and crop coefficients. This tool is available online and considers different planting dates, ENSO phases, and crop growing season lengths. Irrigation needs varied from less than 250 mm per growing cycle during winter to 550 mm during spring. Both El Niño and La Niña influenced the irrigation scheduling, especially from November to March. El Niño periods were related to increased water demand due to drier and warmer conditions, while the opposite was observed for La Niña. The ENSO information might be used to understand climate variability and improve tomato irrigation scheduling in Mozambique