Luiz Carlos Dias Rocha

Selectivity evaluation of insecticides used to control tomato pests to Trichogramma pretiosum

The effects of the insecticides abamectin, acetamiprid, cartap and chlorpyrifos on larvae, pupae (within the host egg) and adults of the egg parasitoid Trichogramma pretiosum Riley (Hym.: Trichogrammatidae) were evaluated under laboratory conditions, using three standard tests described by IOBC. When sprayed on the immature stages of this parasitoid, cartap and chlorpyrifos proved to be the most harmful insecticides, affecting both the emergence success and parasitism capacity of this parasitoid, whereas abamectin and acetamiprid were selective. Abamectin was harmful to adults (residue test on glass plates), slightly harmful to larvae, and moderately harmful to pupae (sprayed on the immature stages within host eggs Anagasta kuehniella (Zeller)); acetamiprid was moderately harmful to adults, harmless to larvae, and slightly harmful to pupae; cartap was harmful to adults, moderately harmful to larvae and harmful to pupae; chlorpyrifos to adults, harmless to larvae and harmful to pupae.

Toxicidade de produtos fitossanitários utilizados na cultura do crisântemo para ovos e ninfas de Orius insidiosus (Say) (Hemiptera: Anthocoridae)

The objective of this study was to evaluate the toxicity of some pesticides used in chrysanthemum crops to eggs and nymphs of Orius insidiosus (Say). The bioassays were carried out at 25 +/- 2 degrees C, 70 +/- 10% RH and 12h photophase. For the tests with eggs, stems of Bidens pilosa L. previously exposed to predator oviposition were dipped for five seconds in aqueous dilution of the pesticides, using 40 eggs per treatment. The pesticides were applied on nymphs using a Potters tower. Forty first-instar and twenty second-instar nymphs of O. insidiosus were used per treatment in the tests with nymphs. The adults from eggs and nymphs treated were grouped in couples to study the pesticides effects on its reproductive parameters. None tested pesticide affected the viability of treated eggs. Azoxystrobin, benomyl, imibenconazole, iprodione, metalaxyl + mancozeb and triforine were harmless to first- and second-instar nymphs of O. insidiosus, whereas abamectin, acephate and chlorfenapyr were shown to be harmful to nymphs of both first and second instars. The pre-oviposition period, the daily number of eggs, number of eggs in ten days, and egg viability were not affected by azoxystrobin, benomyl, imibenconazole, iprodione, metalaxyl + mancozeb and triforine. These pesticides, for showing low toxicity to the predator, can be recommended in disease management programs for chrysanthemum crops, in association with O. insidiosus.

Produtos naturais e sintéticos no controle de Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepdoptera: Lyonetiidae) e seus efeitos sobre a predação por vespas

O controle do bicho-mineiro-do-cafeeiro Leucoptera coffeella (Guerin-Meneville & Perrottet, 1842) e realizado por meio de inseticidas de amplo espectro de acao, capazes de causar desequilibrios biologicos, sendo importante a busca por produtos que apresentem toxicidade a praga e seletividade aos seus inimigos naturais. Objetivou-se, com este trabalho, avaliar a acao dos produtos naturais, extrato pirolenhoso Biopirol® a 2,0; 4,0; 8,0 e 16,0% e azadiractina Nim-I-Go® a 0,25; 0,50; 0,75 e 1,0% em comparacao com os inseticidas sinteticos lambdacialotrina (0,01 mg i.a./mL) e etion (1,5 mg i.a./mL) sobre o bicho-mineiro e seus efeitos sobre vespas predadoras desta praga, em condicoes de campo. Para isto, foi instalado um experimento em uma area de aproximadamente 1,2 ha, em lavoura cafeeira da cultivar Catuai Vermelho, situada em Lavras, MG. As concentracoes do extrato pirolenhoso e de azadiractina avaliadas nao controlaram o bicho-mineiro e nao afetaram negativamente a capacidade predatoria das vespas. Observou-se que etion causou efeito letal as lagartas, logo apos sua aplicacao, decrescendo ao longo do tempo. Lambdacialotrina apresentou menor toxicidade as lagartas logo apos sua aplicacao, seguido por um aumento significativo de controle da praga ao longo do tempo.

Age of onset in patients with Alzheimer’s disease with different apoE genotypes

Alzheimer’s disease is the most common form of dementia, affecting about 10% of the elderly population. Four genetic loci have so far been implicated in Alzheimer’s disease, either in rare family pedigrees in which the defective gene (amyloid precursor protein, presenilin-1, presenilin-2) cosegregates with early onset Alzheimer’s disease, or in late onset cases in which polymorphism of the apolipoprotein E (ApoE) gene on the chromosome 19 is identified as an important individual risk trait. Apolipoprotein E is a normal constituent of plasma lipoproteins and has an important role in the maintenance of the integrity of the neuronal membrane and myelin sheath, but is also deposited in senile plaques in Alzheimer’s disease. Three allelic forms of the ApoE gene have been characterised—Apo e2, Apo e3, and Apo e4. In a previous study, we found that the Apo e4 allele constitutes a major risk factor for Alzheimer’s disease in the Portuguese population,1similar to that described for …

Seletividade de inseticidas para ovos e ninfas de Orius insidiosus (Say) (Hemiptera: Anthocoridae)

O predador Orius insidiosus (Say) alimenta-se de tripes, afideos, moscas-brancas, acaros e pequenas lagartas, contribuindo para a regulacao populacional dessas pragas em diferentes agroecossistemas. Este trabalho teve por objetivo avaliar a seletividade dos inseticidas abamectina, cartape, ciromazina, fempropatrina e imidaclopride, registrados para a cultura do crisântemo, para ovos e ninfas de 1o, 2o e 3o instares de O. insidiosus. Os produtos foram pulverizados em torre de Potter, sendo utilizadas as maiores doses recomendadas para o controle de pragas na cultura do crisântemo. Apos a pulverizacao, os ovos e ninfas foram mantidos em condicoes controladas, com temperatura de 25 ± 1oC, UR de 70 ± 10% e fotofase de 12h. Avaliaram-se a duracao do periodo embrionario, a viabilidade dos ovos e a duracao e sobrevivencia de ninfas. Os ovos de O. insidiosus foram tolerantes a todos os inseticidas. Cartape e ciromazina foram seletivos as ninfas de 1o, 2o e 3o instares, enquanto que os demais produtos foram toxicos. Fempropatrina provocou 100% de mortalidade de O. insidiosus nos tres instares avaliados. Os inseticidas cartape e ciromazina podem ser recomendados para uso em programas de manejo integrado de pragas na cultura do crisântemo.

Toxicidade de produtos fitossanitários para adultos de Orius insidiosus (Say) (Hemiptera: Anthocoridae)

PESTICIDE TOXICITY TO ADULTS OF ORIUS INSIDIOSUS (SAY) (HEMIPTERA: ANTHOCORIDAE) The aim of this work was evaluate the toxicity of abamectin, acephate, azoxystrobin, benomyl, chlorfenapyr, imibenconazole, iprodione, metalaxyl + mancozeb and triforine on adults of Orius insidiosus (Say). These pesticides were used at the concentrations indicated by the manufacturers. All of them are in testing process for pest and diseases control on chrysanthemums crop, and were spraying on adults using a Potters tower. The bioassays were carried out in laboratory, under controlled conditions at 25±2oC,

Seletividade de inseticidas utilizados em cultura cafeeira para larvas de Cryptolaemus montrouzieri Mulsant

As well as most of the crops, in coffee crop, the association of selective compounds and natural enemies, composes an important tool for the integrated pest management (IPM). The objective of this study was to evaluate the selectivity of some pesticides used in coffee crops on larvae of Cryptolaemus montrouzieri Mulsant, 1853 (Coleoptera: Coccinellidae) under controlled laboratory conditions (climatic chamber) at 25±2°C, RH of 70±10% with a 12 h-photophase. The randomized experimental design was used, with six treatments and ten repetitions, being each composed for two larvae. For the comparisons of the averages of treatments, a factorial scheme was used with the products x number of instars for the different instars subsequent the application. The pesticides and doses in g of a.i. L-1 were: thiamethoxan (0.5), imidacloprid (0.7), mineral oil (13.3), endosulfan (2.63) and dimethoate (0.48). Distilled water was used as control. The sprayings of the pesticides were accomplished using a Potters tower. The parameters evaluated were: specimens survival after the application of the compounds, and the compounds effects over the reproductive parameters of the predator. Thiamethoxan (0.5), imidacloprid (0.7) and endosulfan (2.63) were the most harmful to the treated individuals and for the first two compounds it was observed 100% of larvae mortality of the first and second instars soon at 1 day after the application and reduction in the survival of the larvae of third and fourth instars. Dimethoate (0.48) was harmful for the larvae of the first instar and slightly harmful for larvae of fourth instar. As a function of the selectivity presented by mineral oil (13.3), it can be recommended aiming its compatibilization with the C. montrouzieri natural enemy in programs of IPM in coffee crop.

Avaliação da toxicidade de inseticidas utilizados em roseira para adultos de Orius insidiosus (Say) (Hemiptera: Anthocoridae)

Predatory bugs of the genus Orius have been used as entomophagous agents in several agricultural systems, obtaining success in the control of different pests. In rose crops these bugs can be used in the control of thrips, the principal pest of this crop. This study aimed to evaluate the impact of some insecticides used in rose crops to adults of Orius insidiosus (Say), by direct spraying on the bugs and by ingesting contaminated food. Commercial formulations of the insecticides used (g a.i. 100 mL -1 ) were: endosulfan (0.021), formetanate (0.04), spinosad (0.0144) and deltamethrin (0.0008). Out of these, only endosulfan was evaluated as for ingestion of contaminated food test. Distilled water was used as control. The bioassays were carried out in laboratory. A Potter’s tower was used to spray the products on adults. Eggs of Anagasta kuehniella (Zeller) were dipped in the insecticide solutions and offered to the predator. The mortality, the reproduction and the predatory capacity of the survivors were evaluated. By spraying, deltamethrin was harmful to adults of O. insidiosus ; spinosad was moderately harmful and endosulfan and formetanate were slightly harmful. In contaminated food tests, endosulfan was slightly harmful. The predatory capacity of O. insidiosus was not affected by endosulfan in neither of the tests.

Ocorrência de fungos micorrízicos arbusculares, nematóides e ácaros em solos sob diferentes sistemas de cultivo cafeeiro no sul de Minas Gerais

O presente trabalho teve como objetivo estudar ocorrencia de FMAs, nematoides e acaros em solos sob diferentes sistemas de cultivo cafeeiro no Sul de Minas Gerais, em quatro estacoes distintas: verao, outono, inverno e primavera. Foram amostradas areas sob sistema de cultivo cafeeiro safra-zero, convencional e orgânico. Para cada uma das amostras de solo coletadas na camada de 0 a 20cm realizou-se a extracao de esporos, nematoides e acaros, adotando-se a tecnica do peneiramento umido seguido de centrifugacao em sacarose a 50%. A contagem dos microrganismos foi realizada por meio de uma placa canaletada, com auxilio de microscopio estereoscopico. As praticas de manejo ou sistemas de cultivo adotado em cada uma das tres areas em estudo apresentaram influencia na variacao da densidade dos microrganismos analisados nas quatro estacoes do ano. A maior densidade de esporos foi obtida no solo sob sistema orgânico no periodo do outono e a menor media foi obtida no solo sob sistema convencional no periodo do inverno. A maior ocorrencia de acaros foi no solo sob sistema orgânico no periodo do verao e a menor ocorrencia foi no solo sob sistema convencional no inverno. Para os nematoides a maior ocorrencia foi observada no verao em solo sob sistema convencional e a menor densidade foi obtida no inverno em solo sob sistema orgânico.

Toxicidade de produtos fitossanitários utilizados na cultura do crisântemo para ninfas de Orius insidiosus

O objetivo do presente estudo foi avaliar os efeitos letal e subletal de produtos fitossanitarios utilizados na cultura do crisântemo sobre ninfas de (Say, 1832). Os experimentos foram conduzidos no Laboratorio de Estudos de Seletividade do Departamento de Entomologia da Universidade Federal de Lavras (UFLA), Lavras, MG, em câmara climatica a 25±2oC, UR de 70±10% e fotofase de 12 horas. Os produtos foram utilizados na maior dose recomendada pelo fabricante para o controle de pragas e doencas. Foram utilizadas 20 ninfas de terceiro instares 40 ninfas de quarto e quinto instares/tratamento. A aplicacao dos produtos foi realizada por meio de torre de Potter, avaliando-se o efeito dos produtos nos tres estadios ninfais de O. insidiosus. As caracteristicas biologicas avaliadas foram: sobrevivencia das ninfas, periodo de pre-oviposicao, oviposicao diaria por dez dias e a viabilidade dos ovos oriundos de femeas tratadas na fase ninfal. Azoxystrobin, benomyl, imibenconazole, iprodione, metalaxyl + mancozeb e triforine foram seletivos para todos os instares de testados. Abamectin, acephate e chlorfenapyr mostraram-se toxicos a todos os estadios ninfais do predador avaliados. O periodo de pre-oviposicao, o numero medio diario de ovos colocados e por dez dias, e viabilidade de ovos nao foram afetados por azoxystrobin, benomyl, imibenconazole, iprodione, metalaxyl + mancozeb e triforine. Esses produtos, em funcao da baixa toxicidade apresentada, podem ser recomendados no manejo de pragas e doencas da cultura de crisântemo em associacao com o predador O. insidiosus.