Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is a serious pest of corn in several American countries. It is mainly controlled with synthetic insecticides. The objectives of this study were to evaluate the effects of the natural products, neem oil and pyroligneous extract, and the synthetic insecticide, lufenuron, at 2.50 mL water (0.25%) on the mortality of 2-, 4- and 6-day-old caterpillars of S. frugiperda, and their selectivities against fourth instar larvae of Eriopis connnexa Germar (Coleoptera: Coccinellidae). Four- and 6-day-old S. frugiperda caterpillars showed higher mortality after exposure to neem oil (83.33 +/- 0.83 and 89.58 +/- 0.90%, respectively) and lufenuron (95.83 +/- 0.96 and 85.41 +/- 0.83%), compared to pyroligneous extract (68.75 +/- 0.69 and 31.25 +/- 0.31%). The deleterious effect of pyroligneous extract was higher in 2- (83.33 +/- 0.83% mortality) and 4-day-old (68.75 +/- 0.69%) S. frugiperda caterpillars than in 6-day-old caterpillars (31.25 +/- 0.31%). Larval mortality of the predator E. connexa was lower with neem oil and pyroligneous extract (25.00 +/- 0.33%) than with lufenuron (91.66 +/- 1.22%). Neem oil is thus recommended for control of S. frugiperda because of its high toxicity, combined with its relatively low toxicity to larvae of the natural enemy E. connexa.
-Podisus nigrispinus are bedbug predators that are used as biological control agents of defoliating larvae in eucalypt plantations. The mass rearing of natural enemies produces large numbers of insects, but the number of predators produced may not coincide with the timing of the outbreaks of pest populations in the field. The aim of this study was to evaluate the effects of different storage periods on the eggs of P. nigrispinus at low temperatures of 5, 13 and 15°C. The treatments consisted of periods of 5, 10, 15 and 20 days of storage of predator eggs at each temperature indicated. After the different periods of storage, the eggs were removed, and the egg viability, the survival and duration of nymphal instars and the sex ratio of emerged adults were evaluated. Egg storage at 5°C reduced the percentage of hatched eggs, while viability values close to 50% were observed for storage periods of up to 10 days at 13°C and up to 15 days at 15°C. For these treatments, the survival rates of nymphs were similar to those of the control. The different storage periods had no effect on the duration of the nymphal stage or the sex ratio of P. nigrispinus at any of the temperatures. Therefore, the storage temperature of 5°C caused the death of the majority of the embryos, while it is possible to store P. nigrispinus eggs up to 10 and 15 days at 13 and 15°C, respectively. Keywords: Biological control; Mass rearing; Cold storage. ARMAZENAMENTO DE OVOS DO PREDADOR Podisus nigrispinus (HEMIPTERA: PENTATOMIDAE) EM BAIXAS TEMPERATURASRESUMO -Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) são percevejos predadores utilizados como agentes de controle biológico de lagartas desfolhadoras em florestas de eucalipto. Criações massais de inimigos naturais produzem grande número de insetos, mas o número de predadores produzidos pode não coincidir com a época de surtos populacionais de pragas no campo. O objetivo deste trabalho foi avaliar o efeito de diferentes períodos de armazenamento em ovos de P. nigrispinus em baixas temperaturas (5 °C, 13 °C e 15°C ). Os tratamentos consistiram dos períodos de armazenamento (cinco, 10, 15 e 20 dias) dos ovos do predador nas temperaturas indicadas. Após os períodos de armazenagem, os ovos foram retirados e avaliados os parâmetros: viabilidade dos ovos, sobrevivência e duração do estádio ninfal e razão sexual dos adultos emergidos. Os períodos de armazenamento de ovos a 5°C reduziram a porcentagem de ninfas eclodidas inviabilizando a maioria dos ovos. Enquanto valores de viabilidade próximos a 50% foram observados para os períodos de armazenamento de até 10 dias para 13 °C e 15 dias armazenados a 15 °C, com taxas de sobrevivência de ninfas, similares às do controle. Não houve efeito na duração do estágio ninfal e na razão sexual de P. nigrispinus nos tratamentos 878
The expansion of dryeration may impose a further problem for insect control with protectants -the high grain temperatures during insecticide spraying. To assess the impact of this procedure on insecticide activity, maize grains at different temperatures (25, 30, 35, 40 and 45°C) were sprayed with pirimiphos-methyl. Residue analyses were carried out every 30 days and insecticide biological activity towards Sitophilus zeamais and Tribolium castaneum was assessed every 15 days throughout the experimental period of 90 days. Insect mortality was evaluated after 48 h. Pirimiphos-methyl residue decreased with increased storage time and grain temperature during spraying. Similar trends were also observed for mortality of S. zeamais and T. castaneum, which dropped from around 100% for lower grain temperatures, shortly after spraying, to mortality values around 0% for higher temperatures and after 90 days of storage. These results indicate the drastic effect of grain temperatures during spraying, which compromises the efficiency of grain protectants for insect pest control on stored grains. Key words: Sitophilus zeamais, Tribolium castaneum, organophosphate, residue, insect controlEficácia biológica e persistência do pirimifós-metil aplicados sobre grãos de milho em diferentes temperaturas RESUMO A técnica de seca-aeração pode causar problema no controle de insetos devido à alta temperatura do grão durante o processo de pulverização do inseticida. Com este trabalho objetivou-se avaliar o efeito imediato e latente da temperatura do grão durante o processo de pulverização sobre a persistência e eficácia biológica do inseticida pirimifós-metil no controle de Sitophilus zeamais e Tribolium castaneum. Para tal, pulverizou-se o inseticida pirimifós-metil sobre os grãos de milho quando se apresentavam nas temperaturas de 25, 30, 35, 40 e 45°C. A análise de resíduo foi realizada após a pulverização e a cada 30 dias, até 90 dias. Para avaliação da eficácia biológica 20 insetos adultos de S. zeamais e de T. castaneum foram colocados em uma placa de Petri contendo grãos tratados e, após 48 h de exposição dos insetos aos grãos, logo depois da pulverização e a cada 15 dias, até 90 dias, foram realizadas as avaliações. Observou-se que a eficácia biológica do pirimifós-metil reduziu durante o período de armazenamento e que o aumento da temperatura do grão no momento da pulverização também contribui para a redução da eficácia deste inseticida. Observou-se, também, que S. zeamais apresentou menor sensibilidade ao pirimifós-metil que T. castaneum. Palavras-chave:Sitophilus zeamais, Tribolium castaneum, organofosforado, resíduo, controle de inseto 1 UFVJM, CEP 39100-000, Diamantina, MG. Fone: (38) 3532-1226.
-The objective of this work was to evaluate the immediate and latent effects of the grain temperature, during the spraying process, on the persistence and biological efficacy of the biphenthrin insecticide against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). For such, biphenthrin was sprayed on the grain at the temperatures: 25, 30, 35, 40 and 45 o C. To access the persistence of biphenthrin, insecticide residue analyses were carried out monthly, just after spraying until 90 days of storage. To evaluate the biological efficacy of biphenthrin, 20 adults of each species were placed in petri dishes with sprayed grain, and kept in climate cabinets under 27 o C and 55% of RH, during 48h. Evaluations were done every 15 days, starting just after spraying and finishing at 90 days of storage. Both persistence and biological efficacy of biphenthrin reduced as storage time and grain temperatures increased. Additionally, S. zeamais was more tolerant to biphenthrin than T. castaneum.KEY WORDS: Insecticide degradation, insecticide residue, grain temperature, insect control, chemical .....control RESUMO -Os objetivos deste trabalho foram avaliar os efeitos imediato e latente da temperatura do grão, durante a pulverização, sobre a persistência e eficácia biológica do inseticida bifentrina, no controle de Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) e Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Para tal, bifentrina foi pulverizada em grãos de milho com diferentes temperaturas (25, 30, 35, 40 e 45 o C). Para avaliação da sua persistência fez-se a extração e análise do resíduo a cada 30 dias, iniciando logo após a pulverização do inseticida, até os 90 dias de armazenamento. Para avaliação da eficácia biológica, 20 adultos de cada espécie foram colocados em placas-de-petri contendo grãos tratados, sendo mantidas em câmaras do tipo B.O.D., a 27 o C e 55% de UR durante 48 horas. Estas avaliações foram realizadas em intervalos de 15 dias, com início logo após a pulverização e término aos 90 dias de armazenamento. Observou-se que tanto a persistência quanto a eficácia biológica da bifentrina reduziram à medida que o período de armazenamento e a temperatura do grão aumentaram. Observou-se, ainda, que S. zeamais apresentou maior tolerância à bifentrina, que T. castaneum.
The sexual description of adult Psiloptera pertyi was carried out through observations of their external morphological characteristics. Males have their first five abdominal sternites, as well as the seventh and eighth, strongly sclerotized. Females have a similar morphology except the eighth abdominal sternite is not sclerotized. Males have a prominent apex on the seventh sternite, while females have a deep incision in the apical margin of the same segment. Males also have a triangular incision en the extreme posterior margin of the fifth sternite; in females, this segment is rounded. The number and form of the abdominal sternites should be taken into account for sexing adults of P. pertyi.
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