RESUMOO pulgão Rhopalosiphum maidis (Fitch) tem sido encontrado em todos os estádios de desenvolvimento do milho e na maioria dos municípios do Estado de Minas Gerais, e sua importância tem aumentado principalmente nas áreas onde se cultiva o milho safrinha . Por isso, objetivou-se estudar a influência da temperatura sobre alguns aspectos biológicos das fases de ninfa e adulta desse afídeo em diferentes temperaturas em condições de laboratório. Termos para indexação:Pulgão-da-folha-do-milho, temperatura, biologia. ABSTRACTThe aphid Rhopalosiphum maidis (Fitch) has been found in all the development stages of corn and in most towns of Minas Gerais state, Brazil, and its importance has increased mainly in areas where the fall corn is grown. Therefore, it was aimed to investigate the influence of temperature upon some biological features of the nymphal and adult stage at different temperatures under laboratory conditions. The trials were conducted in climatized chamber at 15, 18, 21, 24, 27 and 30 ± 1 o C, RH of 70 ± 10% and 12-hour photophase in the Insect Biology Laboratory of the Entomology Department of the Universidade Federal de Lavras -UFLA, MG, Brazil, in a completely randomized design with five replicates with eight specimens each. A positive correlation among all the developmental stages and the fecundity of R. maidis with temperature was found, except between 24 to 27 o C, where a reduction in fecundity occured, noticing a higher relationship biologic cycle/fecundity at the temperature of 24 o C. It was observed that the duration of the nymphal stage was of 13.3, 10.7, 6.7, 4.5, 4.7 and 4.5 days to 15, 18, 21, 24, 27

Mestre -Instituto Tecnologico Vale, Belém/Pará/Brasil SOUZA, Everaldo Barreiros de Doutor -Instituto Tecnologico Vale, Belém/Pará/Brasil RESUMO: O clima tem influencia direta sobre os animais, considerado um dos principais fatores determinante das zonas biogeográficas no planeta. O excesso de umidade do ar, ocasionado por longos períodos de precipitações, associado as intensas oscilações de temperatura do ar, possuem efeitos diretos sobre a dinâmica populacional dos animais heterotérmicos. Essas influências interferem em diversos aspectos, em especial na instalação, infestação e disseminação destes animais. A Mosca-negra-dos-citros surgiu no Brasil a partir do Estado do Pará, região amazônica com predomínio de elevada umidade do ar e altas temperaturas, ocasionado consideráveis danos às safras de citros no país. O principal objetivo deste trabalho foi à avaliação de áreas de maiores potenciais de infestação dessa praga agrícola, e suas respectivas dinâmicas sazonais em relação aos fatores do clima. Palavras-chave: Bioclimatologia, citricultura, fitossanidade. BIOCLIMATIC DYNAMIC OF BLACK FLY OF CITRUS IN BRAZIL ABSTRACT:The climate has a direct influence on the animals, been considered one of the main determinant factors of the biogeographical zones on the planet. Excess of moisture in the air, caused by long periods of precipitation, associated with intense fluctuations in air temperature, have direct effects on the population dynamics of heterothermic animals. These influences interfere with many aspects, mainly on installation, infestation and dissemination of these animals. The citrus blackfly in Brazil came from the State of Pará, on the Amazonian region with a predominance of high humidity and high temperatures, and since then has caused considerable damage to citrus crops in the country. The main objective of this study was evaluation of areas with the greatest potential for agricultural pest infestation of this kind, and their seasonal dynamics in relation to climate factors.

RESUMOObjetivou-se estudar alguns aspectos biológicos, a capacidade predatória e a resposta funcional de larvas de Chrysoperla externa (Hagen) alimentadas com ninfas de segundo e terceiro ínstares do pulgão Rhopalosiphum maidis (Fitch), em cinco densidades. Os ensaios foram conduzidos em câmaras climatizadas reguladas a 25 ± 1 o C, UR de 70 ± 10% e fotofase de 12 horas. Para o estudo de biologia e capacidade predatória, o delineamento foi inteiramente casualizado, com cinco repetições e oito indivíduos/repetição, totalizando 40 larvas e, para a resposta funcional, os tratamentos corresponderam a cinco densidades de presa e cinco repetições com dois indivíduos/repetição. As observações foram realizadas às 24, 48 horas e no final de cada ínstar. O consumo aumentou proporcionalmente em função do estádio de desenvolvimento da larva, sendo maior no terceiro instar, com 279,1 pulgões, representando aproximadamente 82,0% do consumo total. Observaram-se uma duração de 11 dias para a fase larval e uma viabilidade de 100% em todos os está-dios de desenvolvimento. Para os três ínstares e fase larval, constatou-se maior consumo e duração em função do aumento da densidade de presas. Verificou-se uma resposta funcional Tipo II para todos os ínstares. Constatou-se, para larvas de segundo e terceiro ínstares, o menor tempo de busca, e o primeiro ínstar apresentou o maior tempo de manuseio. Termos para indexação:Resposta funcional, crisopídeo, pulgão da folha do milho. ABSTRACTThe aim of this research was to study the biological aspects, predatory capacity and functional response of the immature stages of Chrysoperla externa (Hagen) fed on the aphid Rhopalosiphum maidis (Fitch), in five densities of prey utilizing nymphs of second and third instars. The experiments were carried out in climatic chambers at 25 ± 1 o C, RH of 70 ± 10% and 12-h photophase. For studying the biology, the design was completely randomized with five replicates and eight insects/replicate, having a total of 40 larvae and, for the functional response, the treatments were composed by five densities of prey and five replicates, with two insects/replicate. The readings were done at 24, 48 hours and in the end of each instar. The consumption increased proportionally to the function of the development stages of the larva, with a higher one in the third instar with 279.1 aphids, representing about 82% of the consumption. A length of 11 days for the larval stage was observed, and a survival rate of 100% in all stages. It was possible to observe a higher consumption and length for the three instars and larval stage, related to the increase in prey densities. The functional response of Type II was observed for all instars. The lowest searching time for the average prey density was verified for second and third instars larvae, and the first instar presented the higher handling time. INTRODUÇÃOArtrópodes-praga são fatores limitantes à exploração agrícola. A infestação pelo pulgão Rhopalosiphum maidis (Fitch, 1856) em milho inicia em plantas isoladas, disseminando-se...

Bryophytes are a potential group for the discovery of biologically active substances to pest control. The objective of this study was to evaluate the antifeedant and insecticidal effect of the ethanolic extract of Sematophyllum subsimplex (Hedw). Mitt. on second-instar larvae of Spodoptera frugiperda (JE Smith, 1797) on corn (Zea mays L.) leaves. The bioassay involved placing individual larvae in petri dishes and fed circular corn leaf sections with 50 µl of the extract at concentrations of 2.0%, 1.0%, 0.5% and 0.25% µg/µl, and DMSO (control), with five replicates, in no-choice feeding assays. Herbivory and mortality rates were assessed 24, 48 and 72 hours after application of the extract. The concentration of 0.25 μg/μl had a positive antifeedant effect shortly after 24 hours. All tested concentrations caused high mortality rates, suggesting insecticidal activity. This is the first scientific work to report the antifeedant and/or insecticidal activity of S. subsimplex and can be the basis for botanical insecticide formulation.