-The objective was to evaluate the selectivity of pesticides used in coffee crops to larvae of Chrysoperla externa (Hagen) and their effects on the subsequent developmental stages of the predator. The treatments in g a.i./L of water were: 1 -endosulfan (Thiodan 350 CE -1.75), 2 -chlorpyrifos (Lorsban 480 CE -1.2), 3 -betacyfluthrin (Turbo 50 CE -0.013), 4 -sulphur (Kumulus 800 PM -4.0), 5 -azocyclotin (Peropal 250 PM -0.31), 6 -copper oxichloride (Cuprogarb 500 PM -5.0) and 7 -control (water). The products were sprayed on first, second and third-instar larvae using a Potter's tower. The larvae were individualized in glass tubes and maintained at 25 ± 2 o C, RH of 70 ± 10% and 12h photophase. The toxicity of the pesticides was calculated based in their total effect (E) and classified according to recommendations of IOBC. Chlorpyrifos and betacyfluthrin were harmful to first-instar larvae (E > 99%). Endosulfan, sulphur, azocyclotin and copper oxichloride were harmless to firstinstar larvae and the others were selective. Chlorpyrifos was also toxic to second and third-instar larvae, and the other compounds were selective (E < 30%). None of the pesticides affected the duration and survival rate of pupae or the sex ratio of the adults originated from treated larvae. Endosulfan, sulphur, azocyclotin and copper oxichloride were harmless to the larval stage of C. externa and did not affect the subsequent stages, so that they can be recommended in IPM programs for the coffee crop.KEY WORDS: Insecta, Coffea arabica, green lacewing, insecticide, acaricide, selectivity RESUMO -Avaliou-se a seletividade fisiológica de alguns produtos fitossanitários utilizados em cafeeiro a larvas de Chrysoperla externa (Hagen) e seus reflexos nas fases subseqüentes do desenvolvimento do predador. Os tratamentos avaliados, em g i.a./L de água foram: 1-endosulfam (Thiodan 350 CE -1,75), 2-clorpirifós (Lorsban 480 CE -1,2), 3-betaciflutrina (Turbo 50 CE -0,013), 4-enxofre (Kumulus 800 PM -4,0), 5-azociclotina (Peropal 250 PM -0,31), 6-oxicloreto de cobre (Cuprogarb 500 PM -5,0) e 7-testemunha (água). As pulverizações foram realizadas em larvas de primeiro, segundo e terceiro ínstares de C. externa, por meio de torre de Potter. Em seguida, as larvas foram individualizadas em tubos de vidro e mantidas em câmara climatizada regulada a 25 ± 2 o C, UR de 70 ± 10% e fotofase de 12h. A toxicidade dos produtos foi calculada em função do seu efeito total (E) e categorizada conforme escala proposta pela IOBC. Clorpirifós e betaciflutrina foram nocivos a larvas de primeiro ínstar (E > 99%) e os demais foram seletivos. Clorpirifós foi também tóxico a larvas de segundo e terceiro ínstares, sendo os demais compostos inócuos ao predador (E < 30%). Nenhum dos produtos avaliados afetou a duração e sobrevivência de pupas, ou a razão sexual e fase adulta dos indivíduos provenientes de larvas tratadas. Endosulfam, enxofre, azociclotina e oxicloreto de cobre foram seletivos para larvas de primeiro, segundo e terceiro ínstares de C. externa e não afetaram ...
An. Soc. Entomol. Brasil 29(2): 309-317 (2000) Functional Response of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)Fed on Schizaphis graminum (Rondani) (Hemiptera: Aphididae)ABSTRACT -The functional response of Chrysoperla externa (Hagen) fed on Schizaphis graminum (Rondani) was studied under five densities of prey. The experimental design was completely randomized with five treatments and ten replications. The tests were conducted in growth chambers at 25 ± 1ºC, RH of 70 ± 10% and photophase of 12 hours. Consumption increased in function of prey density in all instars. However, consumption tended to stabilize when a pre established average density of prey was offered, except for the first instar, which showed a constant increase in aphid consumption. The duration of the first and third instars and of the larval phase, as a whole, increased in function of the increased availability of prey. The duration of the second instar, however, decreased in function of increased prey availability. The results for the 1st, 2nd and 3rd instars and the larval phase showed a Type II functional response. Handling and searching time was evaluated for the average density of offered prey. The lowest searching time was verified for second instar larvae while the first instar showed the highest searching and handling time. Handling time diminished progressively with larvae development.
-The objective of this work was to evaluate the effect the insecticides endosulfan (1.05 g a.i./L), esfenvalerate (0.075 g a.i./L), fenpropathrin (0.09 g a.i./L), trichlorfon (0.09 g a.i./L) and triflumuron (0.0375 g a.i./L), used to control Alabama argillacea (Hübner), on eggs and larvae of Chrysoperla externa (Hagen), under greenhouse conditions. Egg viability, duration of the embryonic period and survival of first-instar larvae ecloded from treated eggs were evaluated. For first, second and third-instar larvae treated with the insecticides, subsequent survival of the larvae and pupae, as well as viability of the eggs produced by the emerged adults, were evaluated. The insecticides esfenvalerate and triflumuron caused a significant increase in the embryonic period of C. externa. Endosulfan, fenpropathrin, trichlorfon and triflumuron were highly toxic to larvae, with mortality rates ranging from 71% to 100%. Esfenvalerate caused only about 20% mortality of the first-and thirdinstar larvae and 38% of the second-instar larvae. Besides causing low larval mortality, esfenvalerate did not affect pupae survival or the reproductive capacity of the adults in the studied period, thus showing good potential for use in integrated pest management in cotton crops. Avaliou-se a viabilidade dos ovos, o período embrionário e a sobrevivência de larvas de primeiro ínstar eclodidas desses ovos. Larvas de primeiro, segundo e terceiro ínstares foram pulverizadas com os inseticidas, verificando-se a sobrevivência das pupas obtidas, e a viabilidade dos ovos produzidos pelos adultos emergidos. Esfenvalerate e triflumurom provocaram aumento do período embrionário de C. externa, sendo que nenhum dos inseticidas avaliados causou redução na viabilidade dos ovos. Endosulfam, fempropatrina, triclorfom e triflumurom foram altamente tóxicos à fase larval do predador, acarretando mortalidade de 71% a 100%. Esfenvalerate causou mortalidade média de 20% para larvas de primeiro e terceiro ínstares e de 38% para o segundo ínstar, não afetando a viabilidade das pupas obtidas e a capacidade reprodutiva dos adultos, apresentando possibilidades de recomendação para uso em programas de manejo integrado de pragas na cultura do algodoeiro. PALAVRAS-CHAVE: Crisopídeo, produto fitossanitário, controle biológico A cultura do algodoeiro possui importantes insetos-praga que causam danos consideráveis, destacando-se o curuquerê Alabama argillacea (Hübner). Em altas infestações, essa espécie pode causar prejuízos, desfolhando as plantas prematuramente e incapacitando-as de produzir sementes e fibras maduras. Muitas vezes o manejo desse inseto é realizado com uso de produtos de amplo espectro de ação que podem afetar os insetos benéficos presentes nessa cultura (Gridi-Papp et al. 1992).Os crisopídeos têm despertado interesse dos pesquisadores por serem eficientes predadores de ampla diversidade de presas, tais como pulgões, moscas-brancas, cochonilhas, lagartas, ácaros etc., podendo ser úteis em programas de manejo integrado de pragas para várias cultur...
Clubroot, caused by Plasmodiophora brassicae, is a disease limiting the production of Brassica species. Its severity varies according to the density of the pathogen's resting spores and environmental conditions. Although the soil environment (including its physical, chemical and biological characteristics) is determinant in the development of the disease, little is known regarding these characteristics in tropical regions, such as Brazil. The objective of this study was to investigate the relationships between soil attributes, bacterial population composition and clubroot intensity in a tropical mountain agroecosystem. Soil and plant samples were collected from 17 cauliflower‐producing localities in Nova Friburgo, Brazil. The physical and chemical attributes, the bacterial population composition, the number of pathogen resting spores in the soil samples, and the clubroot severity were evaluated. Based on bacterial population composition, two distinct groups of soils were identified, which varied in attributes such as organic matter, potential acidity, pH and disease severity. The organic matter level was associated with differences in soil acidity, bacterial population composition and disease intensity, but there was not a cause and effect relationship between bacterial population composition and clubroot severity. Under the conditions of this agroecosystem, soils with increased organic matter presented higher acidity potential (H + Al), which was strongly correlated to clubroot severity. Thus, high acidity potential could be a key factor leading to clubroot development in mountain regions of Brazil.
RESUMOAvaliou-se a influência do Bacillus thuringiensis var. kurstaki (Berliner) sobre adultos de Apis mellifera Linnaeus. Os experimentos foram realizados em laboratório a 28 ± 2 o C, UR 70 ± 10% e fotofase de 12 horas. B. thuringiensis foi aplicado com pulverização sobre adultos, e fornecido através de solução aquosa de mel a 50% e em adição à pasta Cândi, utilizando o produto comercial Dipel ® PM. Esse produto quando aplicado com pulverização ou incorporado à pasta Cândi ou à solução aquosa de mel provocou mortalidade de adultos de A. mellifera em todas as concentrações utilizadas, com exceção de 0,25 g de Dipel ® /100 mL adicionado à solução aquosa de mel a 50%. Ao ser incorporado à pasta Cândi, a CL 50 correspondeu a 0,325 g e a CL 90 2,127 g do B. thuringiensis var. kurstaki/60 g de pasta. Adicionado à solução aquosa de mel a 50%, a CL 50 foi de 1,403 g e a CL 90 foi de 7,759 g do B. thuringiensis var. kurstaki/100 mL de solução. Sintomas de infecção pelo B. thuringiensis foram identificados nas abelhas adultas e através do isolamento obteve-se uma cultura dessa bactéria o que comprovou a patogenicidade para adultos de A. mellifera. Termos para indexação:Abelha, toxicidade, inseticida biológico. ABSTRACTThe effects of Bacillus thuringiensis var. kurstaki (Berliner) on adults of Apis mellifera Linnaeus were evaluated. The bioassays were carried out under controlled conditions at 25±2 o C, RH 70±10% and 12-h photophase. Adults of A. mellifera were exposed to the commercial product Dipel ® PM. The following methods were used: direct spraying; supplying Bt with honey aqueous solution; and by a Candy paste added to Bt. B. thuringiensis caused mortality on A. mellifera adults, independent of the method used, except at 0.25 g of Bt/100 mL added to the honey aqueous solution. B. thuringiensis added to the Candy paste showed CL 50 and CL 90 of 0.325 g and 2.127 g of the product to 60 g of Candy paste, respectively. Dipel ® PM added to the honey aqueous solution showed CL 50 and CL 90 of 1.403 g and 7.759 g of B. thuringiensis/100 mL, respectively. Infection symptoms by B. thuringiensis were identified on bees adult and by isolation of this bacterium, the toxicity of B. thuringiensis on A. mellifera was confirmed.
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