Efficacy of the herbicides indaziflam and clomazone on problematic weeds of family poaceae to sugarcane crop

It is believed that indaziflam gives a longer period of weed control compared to clomazone, irrespective of the type or texture of the soil. Thus, the aim of this study was to evaluate pre-emergent control in five problematic weed species of family Poaceae to sugarcane, using the herbicides indaziflam and clomazone in two soils of different textures. Two experiments were carried out, one in a soil of a sandy-loam texture and the other in a clayey soil. For both experiments, a randomised block design of split plots was chosen, with four replications. The treatments consisted of the herbicides indaziflam (75 and 100 g ai ha-1), clomazone (1080 g ai ha-1) and a control with no herbicide. In the subplots, the treatments were Digitaria horizontalis, Panicum maximum, Rottboellia cochinchinensis, Urochloa decumbens and Urochloa plantaginea. Both herbicides were more effective in the clayey soil, but with indaziflam (100 g ai ha-1), more than 90% control of the weeds remained after 240 days after application (DAA), whereas for clomazone, control remained only up to 90 DAA. The herbicide clomazone did not satisfactorily control the weeds in the sandy-loam soil. The herbicide indaziflam did not control U. decumbens in the sandy-loam soil. D. horizontalis and R. cochinchinensis were the most sensitive species to the herbicide indaziflam, irrespective of soil texture.

Copper formulations in bacterial blight control and toxic effects on coffee seedlings

Bacterial blight of coffee (Pseudomonas syringae pv. garcae) is an important coffee disease and can be controlled using antibiotics and copper-based compounds. However, copper-based compounds raise doubts among coffee growers regarding bacterial blight control efficiency and phytotoxic potential. In this work, coffee plants were sprayed with different copper molecules in order to study their efficiency on bacterial blight control and the phytotoxic potential. Seven copper formulations, cuprous oxide, copper oxychloride, copper nitrate, copper hydroxide 1 (water-dispersible granules) and 2 (concentrated suspension), copper sulfate 1 (complexed with gluconic acid) and 2 (Bordeaux mixture) were studied. The copper formulations efficiency was compared with the antibiotic kasugamycin, saline solution, and control. In controlled environmental conditions of temperature, relative humidity, and photoperiod, coffee seedlings were sprayed with the treatments and after 24 hours they were inoculated with Pseudomonas syringae pv. garcae suspension. Disease incidence and severity assessments were performed in a 2-day interval during a 16-day period. Phytotoxicity incidence and severity, mapping, and quantification of copper on the leaf tissue surface, dried leaves weight, and total copper leaf content were assessed 16 days after pathogen inoculation. Data were submitted to the Scott-Knott test (p < 0.05). Cuprous oxide and copper sulfate 2 proved most efficient to bacterial blight control, causing lower phytotoxicity effect, best covering, and persistence on leaf tissues. Copper nitrate and copper sulfate complexed with gluconic acid were more phytotoxicity compared to other copper formulations.

Herbicide efficacy in the fall management of Richardia brasiliensis, Commelina benghalensis, Conyza sumatrensis AND Digitaria insularis

Other herbicides, alone or in combination with glyphosate, may be effective in controlling Richardia brasiliensis, Commelina benghalensis, Conyza sumatrensis e Digitaria insularis. Therefore, the aim of this study was to evaluate the efficacy of herbicides, alone or in combination, in the control of these weeds in the off-season. Three composite experiments were conducted by applying herbicides, alone or in combinations. Experiments 1 and 2 were conducted in Palotina, State of Paraná (PR), Brazil. Experiment 3 in Iporã, PR, Brazil. The three during fall 2017 in fallow areas after soybean harvest. The experiment was a randomized complete block design with 4 replications and weed control at 7, 14, 21, 28, 35, and 42 days after application (DAA). The control of R. brasiliensis and C. benghalensis was evaluated in the three experiments, the control of C. sumatrensis, in experiments 1 and 2, while the control of D. insularis was evaluated only in experiment 3. Data were subjected to analysis of variance and F-test (p < 0.05). The treatment means values of experiments 1 and 2 were compared by Tukey's test (p < 0.05), and the treatment mean values of experiment 3 were grouped by the Scott and Knott test (p < 0.05). Some herbicide combinations were effective in controlling R. brasiliensis, C. benghalensis, in a single or sequential application. Herbicide combinations were effective in controlling C. sumatrensis with sequential application. Herbicide combinations in a single application did not provide satisfactory final control (≥ 80%) for D. insularis.

Spectral responses at visible and near-infrared wavelengths of soybean plants to fungicides / Respostas espectrais em comprimentos de onda visível e infravermelho-próximo de plantas de soja a fungicidas

The study evaluated the efficacy and soybean spectral responses to fifteen foliar fungicide mixtures labeled to control Asian soybean rust. Canopy level reflectance was measured using a multispectral camera onboard a multirotor drone before and two hours after each spray. The third application of fungicides improved control of soybean rust and increased yield. Nevertheless, up to three consecutive foliar fungicides applications did not affect the reflectance of soybean plants at visible and infrared wavelengths. Thus, drones can be a viable strategy for data acquisition regardless of the application of the fungicides.

Esse estudo avaliou a eficácia e as respostas espectrais de plantas de soja a quinze misturas de fungicidas utilizados no controle da ferrugem asiática da soja (FAS). A refletância do nível do dossel foi medida usando uma câmera multiespectral a bordo de um drone multirotor antes e duas horas após cada pulverização. A terceira aplicação de fungicidas melhorou o controle de FAS e aumentou a produtividade. Porém, três aplicações foliares consecutivas de fungicidas não afetaram a refletância de plantas de soja nos comprimentos de onda visível e infravermelho. Assim, drones podem ser uma estratégia viável para aquisição de dados independentemente da aplicação de fungicidas.

Herbicide performance in the control of Conyza spp. where three plant heights

Intensive use of the herbicide glyphosate has led to herbicide resistant Conyza spp. populations. Thus, there is a need to indicate alternative herbicides and the appropriate developmental stage for controlling these populations. This study identifies alternatives for controlling glyphosate-resistant horseweed, with treatment applications at different plant heights. For this purpose, field experiments were conducted in the 2016/17 and 2017/18 crop years. The evaluated treatments were: glyphosate (540 g ae ha-1), glyphosate (1080 g ae ha-1), glyphosate (2160 g ae ha-1), glyphosate (3240 g ae ha-1), glyphosate + 2.4-D (1080 + 1005 g ae ha-1), glyphosate + saflufenacil (1080 + 49 g ae/ai ha-1), paraquat (400 g ai ha-1), diquat (400 g ai ha-1), ammonium glufosinate (600 g ai ha-1), and control (without application). These treatments were applied to plants with a maximum of 5 cm; plants between 6 and 15 cm; and plants between 16 and 25 cm. The results showed that glyphosate did not control weeds, regardless of rate. With the exception of 2,4-D, which needs complementation with sequential application of another contact herbicide, all alternatives were viable for the control of Conyza spp. plants with a maximum height of 5 cm.

Larvicidal activity of plants from Myrtaceae against Aedes aegypti L. and Simulium pertinax Kollar (Diptera)

Abstract INTRODUCTION: Despite their widespread usage, synthetic insecticides and larvicides are harmful for controlling disease-causing mosquitoes owing to the development of resistance. The leaves of Eugenia astringens, Myrrhinium atropurpureum, and Neomitranthes obscura were collected from Marambaia and Grumari restingas. The safety and larvicidal efficacy of their extracts were tested against Aedes (Stegomyia) aegypti L. and Simulium (Chirostilbia) pertinax Kollar. METHODS: The dry leaves were subjected to static maceration extraction using 90% methanol. A. aegypti and S. pertinax larvae were exposed to 7.5, 12.5, and 25.0 µL/mL of the extracts (n= 30). The larvicidal activity after 24 h and 48 h, and the mortality, were determined. The median lethal concentration (CL50) was estimated by a Finney's probit model. RESULTS: M. atropurpureum and E. astringens extracts exhibited the strongest larvicidal effects against A. aegypti. M. atropurpureum extracts (25 µL/mL) caused mortalities of over 50% and 100% after 24 h and 48 h, respectively (CL50 = 11.10 and 9.68 ppm, respectively). E. astringens extracts (25 µL/mL) caused mortalities of 50% and 63.33% after 24 h and 48 h, respectively. High concentrations of N. obscura extracts induced a maximum mortality of 46.66% in A. aegypti larvae after 48 h (CL50= 25 ppm). The larvae of S. pertinax showed 100% mortality following exposure to all the plant extracts at all the tested concentrations after 24 h. CONCLUSIONS: The extracts of M. atropurpuerum exhibited the strongest larvicidal activity against A. aegypti. The larvae of S. pertinax were sensitive to all the extracts at all the tested concentrations.

Status of Rhipicephalus microplus resistance to ivermectin, fipronil and fluazuron in Mato Grosso do Sul, Brazil / Status da resistência de Rhipicephalus microplus a ivermectina, fipronil e fluazuron em Mato Grosso do Sul

Abstract Southern cattle tick resistance to pour-on and injectable acaricides has yet to be evaluated on a broader scope, and the paucity of information on the subject may hinder efforts to control this parasite. The objective of this study was to evaluate the resistance profile of ten populations of Rhipicephalus microplus to the acaricides fluazuron, fipronil and ivermectin in cattle herds in Mato Grosso do Sul, Brazil. The larval immersion test (LIT) was used to evaluate susceptibility to ivermectin and fipronil and the adult immersion test (AIT) was performed to evaluate fluazuron. Samples were randomly obtained in ten farms, and in general, we found resistance in five samples to fluazuron and in four samples to ivermectin and fipronil. Six samples showed incipient resistance to ivermectin and fipronil. Five of the ten evaluated samples showed resistance and/or incipient resistance to all the active ingredients, and the other five to two active ingredients. Among the samples classified as resistant, the average resistance ratio for ivermectin was 2.75 and 3.26 for fipronil. These results demonstrate the advanced status of resistance to the most modern chemical groups for the control of R. microplus in the state of Mato Grosso do Sul.

Resumo A resistência do carrapato-do-boi a acaricidas com modo de aplicação "pour-on" e injetáveis é pouco avaliada em estudos mais abrangentes, e essa escassez de informação pode resultar falhas no seu controle. Este estudo teve como objetivo avaliar o perfil de resistência em dez populações de Rhipicephalus microplus aos acaricidas fluazuron, fipronil e ivermectina, em rebanhos bovinos em Mato Grosso do Sul, Brasil. A caracterização fenotípica da resistência foi realizada por meio do teste de imersão de adultos (AIT) para o fluazuron, e teste de imersão de larvas (LIT) para fipronil e ivermectina. As amostras foram obtidas aleatoriamente em dez fazendas, sendo diagnosticada resistência em cinco amostras ao fluazuron e em quatro amostras à ivermectina e fipronil. Seis amostras apresentaram resistência incipiente à ivermectina e fipronil. Cinco das dez amostras avaliadas apresentaram resistência e / ou resistência incipiente a todos os princípios ativos, e as outras cinco a dois princípios ativos. Entre as amostras classificadas como resistentes, a média do fator de resistência para ivermectina foi de 2,75 e de 3,26 para fipronil. Esses resultados demonstram o avançado estado de resistência aos mais modernos grupos químicos para o controle de R. microplus em Mato Grosso do Sul.

Emergence and epidemics of a new disease in Araguaia Valley: anthracnosis of cotton caused by Colletotrichum truncatum, varietal reaction and difficulties of chemical control / Epidemias da antracnose do algodoeiro no Vale do Araguaia causada por Colletotrichum truncatum reação de cultivares e dificuldades de controle químico

Cotton culture (Gossypium hirsutum L.) is trending in an upward expansion amidst Brazilian "cerrado". Due this growth, new pathosystems are growing in incidence on tropical fields in the region of Araguaia Valley - MT. Surveys and material collection were conducted out in production areas on two counties (Bom Jesus - MT and Canarana ­ MT), both regions represents a total amount of 50.000 hectares of cultivated area. The region also is characterized by succession areas previously sowed with soybean plants (main cover crop season). Previously surveys revealed the incidence of target spot (Corynespora cassiicola), ramularia spot (Ramularia areola) and cercosporiosis (Cercospora gossypii). Disease incidence is commonly observed on several crop management methods and cultivars. Due to a reduction in efficacy of chemichal control by fungicides spray programs, this disease is increasing and spreading in a faster rate in production areas with previous harvested soybean at the biggest soybean producer group in the world (Bom Futuro). Plants on field were selected due to differences in symptoms, and isolation methods were carried out on PDA (potato-dextrose-agar) before "in vitro" pathogenicity tests conducted on seedlings, detached leaves and bolls (growth chamber conditions of 23°C / photoperiod of 12 hours). After Colletotrichum dextructor sp. pathogenicity confirmation, bioassays were carried out with several different fungicide's groups (i.e. registered for usage on Brazilian jurisdiction). This test consisted of the employment of a solution with 500 ppm of each different fungicide/a.i. that is applied on infected bolls and detached leaves who were inoculated with the target pathogen (concentration of 104 conidia per mL). This test was followed by an infection (%) evaluation during 10 days of incubation. The incidence/prevalence index (%) was also evaluated at different parts of the plant (lower, middle, and upper canopy) on different cultivars/genotypes (130-150 days after sowing). A standard level of control by different fungicides, ranged between 0 to 100% of control. Two groups of cultivars/genotypes were separated after differences on resistance response, one with susceptible traits (FM 985 GLTP) and other with partial resistance traits. No immunity response was observed. We suggest that new efficacy tests should be carried out with combination of varietal response (resistance or tolerance) combined with other chemical fungicides for better understanding of synergism or positive interaction. Valuable information will highlight the best association for greater varietal response and yield against this necrotrophic pathogen (higher B0 ­ initial inoculum) survival during successive years of rotation main crop (cotton x soybean). Isolated spray of benzimidazoles, cupric (except cuprous oxide) and triple associations with triazoles or triazolinthione (prothioconazol) combined with strobilurins and carboxamides should be wisely administrated to manage this disease due to low efficiency (below 50%). New field and laboratory essay must be carried out to input data about resistance risk and clarify damage levels on leaves and bolls impacting yield.

O algodoeiro Gossypium hirsutum L. está em plena expansão no Brasil em área da Bahia e Mato Grosso. Em função dessa expansão novos patossistemas podem ocorrer nas áreas tropicais na região do Vale do Araguaia - MT. Foram realizados levantamentos em áreas de produção nos municípios de Bom Jesus ­ MT e Canarana ­ MT nas áreas de expansão da cultura que atingem mais de 50.000 ha. Nessa região o cultivo é realizado após o cultivo da soja em uma sucessão. São comuns nessas áreas a mancha alvo (Corynespora cassiicola), mancha de ramularia (Ramularia areola) e a Cercosporiose (Cercospora gossypii). Devido as falhas nos programas, com diferentes fungicidas de controle foram realizadas inspeções nas áreas de produção do grupo Bom futuro em diferentes cultivares e sistemas de manejo. Em função da sintomatologia diferenciada e constando-se ser um novo problema foram realizados isolamentos em BDA (batata-dextrose-ágar) e realizados testes de patogenicidade em plântulas, folhas e maçãs destacadas na temperatura de 23o Celsius e regime alternado de luz do dia por 12 horas. Após a confirmação da patogenicidade em plântulas, folhas destacadas, maçãs ou capulhos para Colletotrichum truncatum foram realizados bioensaios com todos os grupos de fungicidas registrados no Brasil. Foram usada a concentração de 500 (mg.kg-1) ppm dos ingredientes ativos, de cada formulação ou fungicida. Após a pulverização dos fungicidas foi em seguida inoculado o patógeno na concentração de 104 conídios por ml. Avaliou-se 10 dias após a incubação a porcentagem de infecção nas folhas destacadas, assim como o percentual de infecção em cada maça inoculada pelo patógeno. Confirmou-se um nível de controle pelos diferentes fungicidas variando de 0 a 100 %, tanto para folhas, como para maças destacadas. Também foi avaliado o índice de prevalência (%), considerando os três terços da planta (terço inferior, médio e superior), em diferentes genótipos em condições de campo na fase final da produção das plantas (130-150 dias). Os genótipos foram suscetíveis (FM 985 GLTP) e muitos genótipos apresentaram resistência parcial. Nenhum genótipo foi imune ao patógeno. Sugere-se a revisão dos programas e manejo com fungicidas visando alternar os melhores ingredientes ativos para o novo patógeno, associado aos genótipos como maior resistência varietal, uma vez que o patógeno pode sobreviver de um ano para o outro em sementes e restos culturais. Fungicidas benzimidazóis, cúpricos (exceto óxido cuproso), benzimidazol + triazol + estrobilurina e carboxamida + triazolintiona + estrobilurina devem ser usados com cautela no controle da doença em função da sua baixa eficiência (abaixo de 50 %), em condições de laboratório (folhas e frutos ­ maçãs destacadas).

Nebulización térmica intradomiciliar de la mezcla de flupyradifurona y transflutrina en mosquitos Aedes aegypti susceptibles y resistentes a piretroides en el Sur de México / Indoor thermal fogging of the mixture of flupyradifurone and transflutrin on Aedes aegypti mosquitoes susceptible and resistant to pyrethroids in southern Mexico

Resumen: Objetivo: Evaluar la efectividad de la mezcla de flupyradifurona 26.3 g/L y transflutrina 52.5 g/L aplicada como niebla térmica a mosquitos Aedes vectores de virus dengue, Zika y chikungunya. Material y métodos: Se colocaron grupos de 15 mosquitos de Ae. aegypti (susceptibles y resistentes a piretroides) dentro de jaulas, en sala, recámara y cocina. Posteriormente, se aplicó la mezcla de flupyradifurona y transflutrina dentro de las viviendas a una dosis de 2 y 4 mg/m3, respectivamente. Resultados: La mezcla de flupyradifurona y transflutrina causó mortalidades de 97 a 100% sobre las cepas de mosquitos Aedes y su efectividad fue la misma en los diferentes compartimentos de las viviendas. Conclusiones: La mezcla de flupyradifurona y transflutrina, aplicada en niebla térmica, es una herramienta prometedora para el control de poblaciones de mosquitos Aedes independientemente de su estado de resistencia a insecticidas.

Abstract: Objective: To evaluate the efficacy of thermal fogging of a mixture of flupyrafirudone (26.3 g/L) and transfluthrin (52.5 g/L) against dengue, Zika y chikungunya Aedes mosquito vectors. Materials and methods: Groups of 15 caged Ae. aegypti (susceptible and pyrethroid resistant) mosquitoes were placed in living room, kitchen and bedroom inside houses, after which a dose of 2 and 4 mg/m3 of flupyradifurone and transfluthrine, respectively, was applied as thermal fog. After one hour of exposure mosquitoes were transferred to the laboratory and mortality was recorded after 24 h. Results: The mixture killed 97 to 100% of mosquitoes from the strains and the efficacy was similar independently of their place within the premises. Conclusions: The mixture of flupyrafirudone and transfluthrin applied as thermal fog is a promising tool to control Aedes mosquito populations independently of the pyrethroid-insecticide resistance status.

Activity of insecticides on coffee berry borer (Hypothenemus hampei) (Coleoptera: curculionidae, scolytinae) / Atividade de inseticidas sobre a broca do café (Hypothenemus hampei) (Coleoptera: curculionidae, escolitinae)

The objective of this work was to evaluate the topical, residual and agronomic effects of the insecticides Voliam Targo, Benevia, Lorsban 480 BR, Curbix 200 SC, Sperto, Verismo, Polytrin 400/40 CE, Curyom 550 EC, Polo 500 SC and Vertimec 18 EC in the control of the berry borer of coffee (H. hampei). The experimental design was completely randomized and four replicates were used in the trials. In the laboratory, a direct spray was sprayed on the insect (topical effect) and applied to the fruits of the coffee (residual contamination). In both experiments, each plot consisted of a Petri dish lined with filter paper, 10 fruits in the green stage and 10 adult females of the berry borer, originating from artificial breeding. Two field experiments were carried out at Campus Glória Experimental Farm. The first one was carried out with the objective of evaluating the residual effect of the insecticides on artificial infestation of the berry borer after applying the products to fruits at the beginning of maturation. The number of perforated fruits, dead females, number of eggs and larvae were evaluated in laboratory and field experiments. The second field experiment had as objective to evaluate the effectiveness in controlling the natural population of the berry borer. Two applications were performed with a 30-day interval, using a motorized turbocharger. The number of fruits bored in 50 fruits per plot and percentage of seeds bored in a sample of 250 seeds per replicate were evaluated. In the laboratory, all insecticides provided mortality higher than 80% in topical application and greater than 73% by residual contamination, except the insecticide Polo 500 SC, which provided a 55% mortality. In the field experiment with artificial infestation, all the insecticides differed from the control, maintaining residual control until 30 days after application and with mortality higher than 70%, reaching up to 100% of mortality. In the test with natural berry borer females infestation the insecticides differed from the control in all evaluated parameters, showed efficacy higher than 75% at 35 days after the second application. The insecticides Voliam Targo, Lorsban 480 BR, Curbix 200 SC, Sperto, Polytrin 400/40 CE and Verismo presented the best control results, being indicated for use in the management of the berry borer of coffee.

O objetivo deste trabalho foi avaliar em laboratório e em campo os efeitos tópicos, residuais e de eficiência agronômica dos inseticidas Voliam Targo, Benevia, Lorsban 480 BR, Curbix 200 SC, Sperto, Verismo, Polytrin 400/40 CE, Curyom 550 EC, Polo 500 SC e Vertimec 18 EC no controle da broca do café (H. hampei). O delineamento experimental foi inteiramente casualizado e quatro repetições foram utilizados nos ensaios. No laboratório foi feita uma pulverização direta sobre o inseto (efeito tópico) e uma aplicação nos frutos do café (contaminação residual). Em ambos os experimentos, cada parcela consistiu de uma placa Petri forrada com papel de filtro, 10 frutos no estágio verde e 10 fêmeas adultas da broca, originários de criação artificial. Dois experimentos de campo foram realizados na Fazenda Experimental Campus Glória. O primeiro foi realizado com o objetivo de avaliar o efeito residual dos inseticidas em infestação artificial da broca após a aplicação dos produtos em frutos no início da maturação. Foram avaliados o número de frutos perfurados, fêmeas mortas, número de ovos e larvas nos experimentos de laboratório e campo. O segundo experimento de campo teve como objetivo avaliar a eficácia no controle da população natural da broca. Foram realizadas duas aplicações com intervalo de 30 dias, utilizando-se um turbo pulverizador motorizado. Foram avaliados o número de frutos perfurados em 50 frutos por parcela e porcentagem de sementes brocadas em uma amostra de 250 sementes por repetição. No laboratório, todos os inseticidas proporcionaram mortalidade superior a 80% em aplicação tópica e maior de 73% por contaminação residual, exceto o inseticida Polo 500 SC, que proporcionou 55% de mortalidade. No experimento de campo com infestação artificial, todos os inseticidas diferiram da testemunha, mantendo o controle residual até 30 dias após a aplicação e com mortalidade superior a 70%, chegando a até 100% de mortalidade. No teste com infestação natural da broca os inseticidas diferiram da testemunha em todos os parâmetros avaliados, mostraram eficácia superior a 75% aos 35 dias após a segunda aplicação. Os inseticidas Voliam Targo, Lorsban 480 BR, Curbix 200 SC, Sperto, Polytrin 400/40 CE e Verismo apresentaram os melhores resultados de controle, sendo indicados para uso no manejo da broca do café.

Herbicide weed control ­ induced differential tolerance and productivity in cowpea plants / Controle de ervas daninhas com herbicida - tolerância diferencial induzida e produtividade em plantas de feijão-caupi

The use of herbicides is a represents an efficient way to control the infesting plant population, since it is associated with low operational cost, and it does not demand large amounts of labour. An obstacle to growing cowpea (Vigna unguiculate) is the absence of herbicides registered for this crop. The objective of this work was to evaluate the tolerance of cowpea to herbicides. The experiment was carried out in a randomised block with treatment controls with and without weeding, Bentazon (720 g ha-1), Fluazifop-p-butyl (250 g ha-1), Fomesafen and a tank mix between Fluazifop-p-butyl + Fomesafen (250 + 187.5 g ha-1) with treatment replicates. The herbicides were applied on vegetative (V3 ­ stage) cowpea plants using a CO2-pressurised backpack sprayer with four spray tips TT 110.02 operating at a pressure of 2.5 bar and applying 240 litres of syrup per hectare. The cultivar BRS Guariba, with five planting lines per plot, was tested with the three central lines of the useful area, scoring 0.5 m of the ends. The species Oxalis latifolia was difficult to control. The Fluazifop-p-butyl + Fomesafen mixture presented better control of weeds. The herbicides caused phytotoxicity to cowpea and reduced leaf area and dry mass. The productivity of the crop was affected due to the low control of weeds. It was concluded that the cowpea presented differential tolerance to the herbicides tested doses.

O uso de herbicidas é uma alternativa promissora, pois permite um controle eficiente da população de plantas infestantes, associado a baixo custo operacional e sem exigir grandes quantidades de mão de obra. No entanto, um entrave no controle de plantas daninhas no feijão-caupi é a ausência de herbicidas registrados para essa cultura. Objetivou-se com este trabalho avaliar a tolerância do feijão-caupi cultivar BRS Guariba, a herbicidas. Um ensaio foi conduzido a campo em blocos casualizados composto dos tratamentos, testemunhas com e sem capina, Bentazon (720 g i.a. ha-1), Fluazifop-p-butyl (250 g i.a. ha-1), Fomesafen (187,5 g i.a. ha-1) e mistura de tanque entre Fluazifop-p-butyl + Fomesafen (250 + 187,5 g i.a. ha-1) com 4 repetições. Os herbicidas foram aplicados com plantas de caupi em estágio vegetativo V3 com pulverizador costal pressurizado por CO2 com quatro pontas de pulverização TT 110.02 operando a uma pressão de 2,5 Bar e aplicando 240 L ha-1 de calda. As parcelas foram compostas 5 linhas de plantio com cinco metros de comprimento, espaçadas de 0,5 m, com as 3 linhas centrais de área útil, desprezando 0,5 m das extremidades. Avaliou-se a comunidade infestante, a eficiência de controle de plantas daninhas, a tolerância e a produtividade do feijão-caupi. A espécie Oxalis latifolia foi encontrada em todos os tratamentos e apresentou difícil controle. A mistura Fluazifop-p-butyl + Fomesafen apresentou melhor controle das plantas daninhas. Os herbicidas ocasionaram fitotoxicidade ao feijão-caupi e redução de área foliar e massa seca de plantas. A produtividade da cultura foi reduzida nos tratamentos com baixo controle de plantas daninhas bem como nos tratamentos que provocaram toxicidade elevada. Conclui-se que o feijão-caupi apresentoutolerância diferencial aos herbicidas nas doses testadas.

Performance of insecticides in control of Diatraea saccharalis (Lepidoptera: Crambidae) in sugarcane / Desempenho de inseticidas no controle de Diatraea saccharalis (Lepidoptera: Crambidae) em cana-de-açúcar

The population of the caterpillar Diatraea saccharalis (Lepidoptera: Crambidae) has increased in the crop of sugarcane in recent years. Although the control of this insect is traditionally carried out through biological control, the use of phytosanitary products has still been necessary. Therefore, the goal of this work was to evaluate the performance of different insecticides in sugarcane borer control, as well as the effect on productivity and total recoverable sugar (TRS). The experiment was conducted in a randomized experimental delineation of blocks, with six treatments and four blocks. Treatments consisted of five insecticides and one control group (without application of insecticide). For calculating the D. saccharalis infestation index, monthly samplings were performed every 30 days, for 12 months. After this period, the final D. saccharalis infestation index was evaluated and calculated for each treatment. In order to compare productivity among procedures, four central lines were collected from each plot. Thus, the samples were weighed for the productivity calculation (TCH) and sent to the laboratory for the total recoverable sugar (TRS) analysis. The chloranthraniliprole (350) insecticide provided a lower index of sugarcane borer infestation, in addition to greater productivity when compared to the other insecticides. There was no significant difference in the parameter of total recoverable sugar (TRS) among treatments.(AU)

A população da lagarta Diatraea saccharalis (Lepidoptera: Crambidae) tem aumentado na cultura de cana-de-açúcar nos últimos anos. Apesar do controle deste inseto ser tradicionalmente realizado através do controle biológico, o uso de produtos fitossanitários ainda tem sido necessário. Portanto, o objetivo deste trabalho foi avaliar o desempenho de diferentes inseticidas no controle da broca da cana-de-açúcar, bem como o efeito sobre a produtividade e o açúcar total recuperável (ATR). O experimento foi conduzido no delineamento experimental de blocos ao acaso, com seis tratamentos e quatro blocos. Os tratamentos foram compostos por cinco inseticidas e um tratamento sem aplicação de inseticida. Para o cálculo do índice de infestação da D. saccharalis foram realizadas amostragens mensais a cada 30 dias, durante 12 meses. Após esse período, foi avaliado e calculado o índice de infestação final da D. saccharalis de cada tratamento. Para comparar a produtividade entre os tratamentos, foram colhidas as quatro linhas centrais de cada parcela. Assim, as amostras foram pesadas para o cálculo da produtividade (TCH) e enviadas ao laboratório para análise do açúcar total recuperável (ATR). O inseticida clorantraniliprole (350) proporcionou um menor índice de infestação da broca da cana, além de maior produtividade, em relação aos demais inseticidas. Não houve diferença significativa do parâmetro de açúcar total recuperável (ATR) entre os tratamentos.(AU)

Stink bug control at different stages of soybean development / Controle de percevejos em diferentes estádios de desenvolvimento da planta de soja

This study evaluates the effects of combinations of pyrethroids and neonicotinoids on the control of stink bugs at different stages of soybean crop development. The experiment was set up in a factorial randomized block design (4×6: 4 treatments and 6 stages) with 4 repetitions. The following treatments were tested during the V6/V7, R2, R4, R5.1, R5.5 and R 6 phenological stages: 1 ­ control (no application), 2 ­ thiamethoxam + λ-cyhalothrin, 3 ­ acetamiprid + α-cypermethrin, and 4 ­ dinotefuran + α-cypermethrin. Infestation, number of damaged seeds, number of pods, number of pods per plant, and yield (kg/ha) were evaluated. Stink bug infestations were smaller when applications commenced during the vegetative stages (V6-V8). Pod numbers and yields were highest in the dinotefuran + α-cypermethrin treatment with applications from V6/V8 to R4. The active ingredients dinotefuran + α-cypermethrin reduced stink bug populations and increased yields and could therefore be considered in integrated pest management (IPM) programs for soybean crops.(AU)

O objetivo deste trabalho foi avaliar o efeito de combinações de piretroides com neonicotinoides no controle de percevejos em diferentes estádios de desenvolvimento da cultura da soja. O delineamento experimental foi em blocos randomizados, em esquema fatorial 4×6 (4 tratamentos e 6 estádios) com 4 repetições. Os produtos utilizados foram: 1 ­ testemunha (sem aplicação), 2 ­ tiametoxam + λ-cialotrina, 3 ­ acetamiprida + α-cipermetrina, e 4 ­ dinotefuran + α-cipermetrina, e as aplicações foram realizadas a partir dos estádios fenológicos V6/V7,R2, R4, R5.1, R5.5 e R6. Avaliaram-se a infestação, número de grãos danificados, número de vagens, número de vagens por planta e produtividade (kg/ha). A infestação de percevejo foi menor quando se iniciou a aplicação precocemente nos estádios vegetativos (V6-V8).O número de vagens e produtividade foi superior no tratamento dinotefuran + α-cipermetrina nos estádios V6/V8 até R4. Os ingredientes ativos dinotefuran + α-cipermetrina apresentaram resultados positivos na redução da população de percevejo e proporcionaram incremento no rendimento de grão, podendo ser utilizado como opção em programa de manejo integrado de pragas (MIP) na cultura da soja.(AU)

Effect of Plumeriarubra(Apocynaceae) leaf extracts, a repellent of rice-field rats (Rattusargentiventer), on its metabolism and daily activity

Introduction: Rice-field rats are one of the most important pests because it can give large losses in all planting seasons including the storehouse. Synthetic rodenticide is the most commonly used of chemical technique for controlling rice-field rats. The application of these materials indirectly causes negative impacts; one of them is for the environment. As an alternative for controlling rice-field rats, natural materials can be used as a repellent. Objective: To examine the effects of methanol extract of Plumeriarubra leaves on metabolism, daily activity patterns, and its potency as a repellent of the rice-field rat. Methods: The experiments were conducted at the Laboratory of Pests, UniversitasPadjadjaran involves choice test (T-maze arena), and the Laboratory of Rats, Indonesian Center for Rice Research involves no-choice test (metabolic cage) from February until May 2019. The observations including food (g), water consumption (ml), feces production (g), urine production (ml), body weight (g), and its changes (%), also the daily activities (time spent for locomotion, foraging, and resting).The treatment was done with three replications for twelve mature male and twelve mature non-pregnant females. Data experiments analysis followed by a T-test. Results: Rice-field rats on the T-Maze arena avoided consuming food and beverage that close to methanol extract of Plumeriarubra leaves treatment. The treatment of methanol extract of Plumeria leaves in metabolic cage caused metabolic disorder of rice-field rat, which was significantly indicated by the decrease of the average consumption of food by 2.28 g and excretion of feces by 0.34 g, and also the increase of average consumption of beverage by 3.89 ml, excretion of urine by 3.15 ml, and body weight by 6.67 g. The treatment also caused daily activity patterns disorder of rice-field rats, which was significantly indicated by the increase of the average percentage of time for movement activities (locomotion) by 7.64 % and the decrease of time for eating and drinking activities (foraging) by 16.46 %. Conclusion: Methanol extract of Plumeria leaves affects a repellent for the rice-field rat.

Introducción: Las ratas arroceras son una de las plagas más importantes porque pueden producir grandes pérdidas en todas las temporadas de siembra, incluso en el almacenaje. La técnica química más utilizada para controlar las ratas de los arrozales es el raticida sintético. Sin embargo, la aplicación de estos químicos provoca indirectamente impactos negativos, por ejemplo, en el ambiente. Una alternativa para controlar la rata arrocera es la utilización de compuestos naturales como repelentes. Objetivo: Examinar los efectos del extracto metanólico de hojas de Plumeria rubra sobre el metabolismo, los patrones de actividad diaria en las ratas arroceras y su potencial como repelente. Métodos: Los experimentos se llevaron a cabo en Laboratory of Pests, UniversitasPadjadjaran usando la prueba T-maze arena, y en Laboratory of Rats, Indonesian Center for Rice Research usando la prueba metaboliccage, desde febrero hasta mayo 2019. Las observaciones incluyeron consumo de alimentos (g), consumo de agua (ml), producción de heces (g), producción de orina (ml), peso corporal (g) y cambios (%), además actividades diarias (tiempo dedicado a la locomoción, búsqueda de alimento, y reposo). El tratamiento se realizó con tres repeticiones para 12 machos maduros y 12 hembras maduras no gestantes. Los análisis de experimentos de datos se realizaron con la prueba T. Resultados: Las ratas arroceras en la T-maze arena evitaron consumir alimentos y bebidas cercanos al extracto de metanol de hojas de Plumeria rubra. El tratamiento del extracto metanólico de hojas de Plumeria rubra en la prueba metaboliccage provocó un trastorno metabólico en estas ratas, lo cual se demostró significativamente en la disminución del consumo promedio de alimento en 2.28 g y la excreción de heces en 0.34 g, además en el aumento del consumo promedio de bebida en 3.89 ml, excreción de orina en 3.15 ml y peso corporal en 6.67 g. El tratamiento también provocó un trastorno en los patrones de actividad diaria de las ratas, lo cual fue demostrado por el aumento significativo en el porcentaje promedio de tiempo para actividades de movimiento (locomoción) en un 7.64 % y la disminución del tiempo para comer y beber (búsqueda de alimento) en un 16.46 %. Conclusión: El extracto metanólico de hojas de Plumeria rubra tiene un efecto repelente en las ratas arroceras.

Resistance of the stable fly, Stomoxys calcitrans (Diptera: Muscidae), to cypermethrin in outbreak areas in Midwestern Brazil / Resistência da mosca-dos-estábulos, Stomoxys calcitrans (Diptera: Muscidae), à cipermetrina em áreas de surtos no Centro-Oeste brasileiro

Abstract Population explosions of the stable fly (Stomoxys calcitrans) have become a serious concern for livestock producers near sugarcane mills in some regions of Brazil due to the insect's massive reproduction on sugarcane byproducts and waste. Despite the limited efficiency of insecticides for controlling stable fly outbreaks, producers still rely on chemical control to mitigate the alarming infestations in affected areas. This study evaluated the susceptibility of S. calcitrans populations to cypermethrin in the state of Mato Grosso do Sul, Brazil. Stable flies were tested from three field populations and two colonies, established from flies previously collected at sugarcane mills. Wild flies were collected with Nzi traps in areas of sugarcane plantations. Both wild and colonized flies were exposed to eleven concentrations of cypermethrin in impregnated filter paper bioassays. All the populations proved to be resistant to cypermethrin, with resistance factors among field populations ranging from 6.8 to 38.6. The intensive use of insecticides has led to the development of pyrethroid resistance in stable fly populations in the proximities of sugarcane mills in the state of Mato Grosso do Sul.

Resumo Explosões populacionais da mosca-dos-estábulos (Stomoxys calcitrans) tornaram-se uma séria preocupação para a pecuária próxima a usinas de cana-de-açúcar em algumas regiões do Brasil, devido à massiva reprodução da mosca em resíduos e subprodutos do processamento da cana. Apesar da limitada eficiência dos inseticidas no controle dos surtos desta mosca, produtores dependem do controle químico para mitigar as alarmantes infestações nas áreas afetadas. Este estudo objetivou avaliar a suscetibilidade de populações de S. calcitrans a piretroides no estado de Mato Grosso do Sul, Brasil. Moscas-dos-estábulos de três populações de campo e duas colônias, estabelecidas a partir de moscas previamente coletadas em usinas de cana-de-açúcar, foram testadas. Moscas selvagens foram coletadas com armadilhas Nzi em áreas de cana. Moscas coletadas foram expostas a onze concentrações de cipermetrina em bioensaios com papel de filtro impregnado. Todas as populações testadas mostraram-se resistentes ao piretroide, com fatores de resistência variando de 6,8 a 38,6 nas populações de campo. O uso intensivo de inseticidas tem levado ao desenvolvimento de resistência da mosca-dos-estábulos a piretroides em populações próximas a usinas de cana-de-açúcar no estado do Mato Grosso do Sul.

Sorption and desorption of ametryn in different types of soils / Sorção e dessorção do ametryn em diferentes tipos de solos

Knowledge of factors related to the dynamics of herbicides in the environment is of fundamental importance to predicting the behavior of herbicides in soils with different attributes, to select appropriate dosages, as well as to avoid harmful effects on the environment and subsequent crops. The objective of this work was to evaluate the sorption and desorption of ametryn in seven soils with different attributes. Initially, the equilibrium time was determined by the "Batch Equilibrium". Then, it was performed the sorption test with different concentrations (0.5; 1; 2; 4; 8; 16; 24 and 32 mg L-1) of ametryn in 0.01 mol L-1CaCl2. 10 mL of these solutions were added to samples of 2.00 g of each soil, remaining under rotary shaking for 4 hours. After centrifugation and filtration, the ametryn concentration in the supernatant was determined by high-performance liquid chromatography. Desorption was evaluated using the tubes containing 16 mg L-1 prior to sorption testing. The results indicated that the sorption and desorption of ametryn depend on the physicochemical attributes of the soil. Sorption was higher in soils with high organic matter content and high ion exchange capacity, while desorption was inversely proportional to sorption.

O conhecimento dos fatores relacionados à dinâmica de herbicidas no ambiente é de fundamental importância para prever o comportamento de herbicidas em solos com diferentes atributos e para seleção de dosagens adequadas, bem como para evitar efeitos prejudiciais ao ambiente e às culturas subsequentes. O objetivo do trabalho foi avaliar a sorção e dessorção do ametryn em sete solos com diferentes atributos. Inicialmente, foi determinado o tempo de equilíbrio pelo método "Batch Equilibrium". Em seguida foi realizado o ensaio de sorção com diferentes concentrações (0,5; 1; 2; 4; 8; 16; 24 e 32 mg L-1) de ametryn em CaCl2 0,01 mol L-1. Foram adicionadas 10 mL destas soluções a amostras de 2,00 g de cada solo, permanecendo sob agitação rotatória por 4 horas. Após centrifugação e filtração, a concentração do ametryn no sobrenadante foi determinada por cromatografia líquida de alta eficiência. A dessorção foi avaliada utilizando os tubos que continham 16 mg L-1 antes do ensaio de sorção. Os resultados indicaram que a sorção e a dessorção do ametryn depende dos atributos físico-químicos do solo. A sorção foi maior em solos com alto teor matéria orgânica e alta capacidade de troca iônica, enquanto que a dessorção foi inversamente proporcional à sorção.

Fungicide spray coverage and deposition in soybean asian rust management / Cobertura e depósito de calda fungicida no manejo da ferrugem asiática em soja

At maximum vegetative growth, sprays with fungicide to control Asian rust (Phakopsora pachyrhizi Sydow and P. Sydow) should reach high canopy penetration and plant coverage. Therefore, the central objective of this study was to determine leaf area, spray deposition, and plant coverage by fungicides sprayed on soybeans as a function of sowing seasons and plant population densities with reduced doses of tebuconazole and azoxystrobin + cyproconazole. Field experiments were conducted in the 2009/2010 and 2010/2011 crop years, using a medium-cycle soybean cultivar MG/BR­46 (Conquista) under a natural infestation of Asian soybean rust. Leaf area (LA) and leaf area index (LAI) were measured at three developmental stages (V8, R2, and R4). Spray deposition and coverage were evaluated during the first fungicide spraying. As results, LAI decreased as plant population decreased. Despite the lower LAIs, smaller plant populations had no effect on spray deposition and plant coverage. Both fungicides presented similar depositions on all thirds when plants had lower development.

Para o controle da ferrugem asiática (Phakopsora pachyrhizi Sydow & P. Sydow), quando as plantas atingem o máximo de desenvolvimento vegetativo, as pulverizações com fungicidas necessitam de alta capacidade de penetração e cobertura. O objetivo deste trabalho foi determinar a área foliar, o depósito e a cobertura de calda fungicida em soja em função de épocas de semeadura, populações de plantas e doses reduzidas de fungicidas. Experimentos de campo foram conduzidos nos anos agrícolas 2009/2010 e de 2010/2011, com a cultivar de ciclo médio MG/BR-46 (Conquista), sob infestação natural da ferrugem asiática. Nos estádios V8, R2 e R4 de desenvolvimento da cultura foram determinados a área foliar e o índice de área foliar (IAF) das plantas. As avaliações de depósito e cobertura foram realizadas no momento da primeira pulverização com os tratamentos fungicidas. Com a redução da população de plantas houve redução no IAF. Os depósitos e coberturas da calda aplicada não apresentaram aumento com a redução da população de plantas, apesar dos menores IAF. Os tratamentos fungicidas com tebuconazol e com azoxystrobina + ciproconazol apresentaram deposições semelhantes em todos os terços das plantas quando as plantas apresentaram menor desenvolvimento.

Impacto ambiental por uso de plaguicidas en tres áreas de producción de melón en la Comarca Lagunera, México / Environmental impact by usage of pesticides in three melon producing areas in the Comarca Lagunera, Mexico

RESUMEN El uso intensivo de plaguicidas altamente tóxicos, en la producción de cultivos hortofrutícolas especializados, conlleva riesgos ambientales y sociales, que pueden medirse mediante indicadores de riesgo de plaguicidas, para evaluar el potencial de impacto negativo de estos productos en los ecosistemas y comparar los logros de la implementación de prácticas agrícolas sustentables, en términos de reducción de riesgos, por la utilización de plaguicidas. El objetivo de esta investigación fue estimar el potencial impacto ambiental, por uso de plaguicidas, en las tres áreas de mayor producción de melón en la Comarca Lagunera. Se realizó un estudio descriptivo transversal, mediante la aplicación de una encuesta en 19 predios, seleccionados mediante muestreo no probabilístico. El Impacto Ambiental (IA) se evaluó mediante el modelo del Cociente de Impacto Ambiental (CIA), que se basa en el cálculo del CIA y el Cociente de Impacto Ambiental en Campo (CIAC). Los resultados muestran que los plaguicidas que contribuyeron con la mayor carga ambiental en las áreas de estudio fueron: clorotalonil (49 %), azufre elemental (11 %) y endosulfan (10 %), en Mapimí; carbofuran (19 %), endosulfan (18 %) y carbendazim (12 %), en Matamoros-Viesca; y oxicloruro de cobre (20 %), endosulfan (17 %) y mancozeb (17 %), en Tlahualilo. Los sistemas de producción, con los valores del IA más altos, se identificaron en fechas de siembra intermedias (199 a 500) y tardías (201 a 701), en Mapimí, y fechas tardías (132 a 383) en MatamorosViesca. El modelo del CIA permitió identificar a los plaguicidas y los sistemas de producción con el mayor impacto ambiental negativo en las tres principales áreas de producción de melón en la Comarca Lagunera, además de proporcionar una escala cuantificable, que permitirá evaluar y comparar futuros cambios en el uso regional de plaguicidas.

ABSTRACT The intensive use of highly toxic pesticides in the production of specialized horticultural crops entails environmental and social risks that can be measured through pesticide risk indicators to assess the potential negative impact of these products on ecosystems. In addition, this measurement enables the comparison of the achievements that result from the implementation of sustainable agricultural practices in terms of risk reduction due to the use of pesticides. The objective of this research was to estimate the potential environmental impact due to the use of pesticides in three melon production areas in the Comarca Lagunera. A cross-sectional descriptive study was carried out by applying a survey in 19 properties selected by non-probabilistic sampling. The Environmental Impact (EI) was evaluated using the Environmental Impact Quotient (EIQ) model, which is based on the calculation of the EIQ and the Environmental Impact Quotient in the Field (EIQF). The results show that the pesticides that contributed with the greatest environmental burden in the study areas were: Chlorothalonil (49 %), elemental sulfur (11 %) and endosulfan (10 %) in Mapimí; carbofuran (19 %), endosulfan (18 %) and carbendazim (12 %) in Matamoros-Viesca, and copper oxychloride (20 %), endosulfan (17 %) and mancozeb (17 %) in Tlahualilo. The production systems with the highest AI values were identified on intermediate (199 to 500) and late (201 to 701) sowing dates in Mapimí and late dates (132 to 383) in Matamoros-Viesca. The EIQ model allowed the identification of pesticides and production systems with the greatest negative environmental impact in the main areas of melon production in the Comarca Lagunera and provides a quantifiable scale that will allow the evaluation and comparison of future changes in the regional use of pesticides.

Effect of seed treatment with insecticides on the control of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in soybean / Efeito do tratamento de sementes com inseticidas no controle de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) na cultura da soja

Fall armyworm is one of the main insect pests in Brazil. Thus, the present work aimed to evaluate the seed treatment effect on the control of Spodoptera frugiperda in initial infestations of soybean crops. The experimental design was completely randomized with four replicates of six insecticide treatments applied through seed treatment: imidacloprid plus thiodicarb at the dose of 52.5 plus 105 g a.i. (active ingredient) 100 kg-1 of seed (Cropstar® 0.350 L 100 kg-1 of seed); thiamethoxam at 105 g a.i. 100 kg-1 of seed (Cruiser 350 FS® 0.3 L 100 kg-1 of seed); chlorantraniliprole at 62.5 g a.i. 100 kg-1 of seed (Dermacor® 0.1 L 100 kg-1 of seed); cyantraniliprole at 120 g a.i. 100 kg-1 of seed (Fortenza 600 FS® 0.2 L 100 kg-1 of seed); fipronil plus pyraclostrobin and thiophanate-methyl 50 + 5 + 45 g a.i. 100 kg-1 of seed (Standak Top® 0.2 L 100 kg-1 of seed), and a control treatment. The experiment was carried out in a greenhouse. Diamide insecticides (chlorantraniliprole and cyantraniliprole) presented the best results among all treatments, with lower consumption of the treated leaves by the caterpillars and greater control efficacy of this insect. We verified that seed treatment is a viable alternative for controlling S. frugiperda at the beginning of crop development, when the caterpillar presents the behavior of cutting the seedlings and/or the consumption of leaf area, causing a reduction in the plant population and a consequent yield loss.(AU)

A lagarta-do-cartucho é um dos principais insetos-praga no Brasil. Assim, o presente trabalho teve por objetivo avaliar o efeito do tratamento de sementes no controle de Spodoptera frugiperda nas infestações iniciais da cultura da soja. O delineamento experimental foi inteiramente casualizado, com quatro amostras replicadas de seis tratamentos inseticidas aplicados via tratamento de sementes: imidacloprida mais tiodicarbe na dose de 52,5 mais 105 g i.a. (ingrediente ativo) 100 kg-1 de sementes (Cropstar® 0,350 L 100 kg-1 de sementes); tiametoxam a 105 g i.a. 100 kg-1 de sementes (Cruiser 350 FS® 0,3 L 100 kg-1 de sementes); clorantraniliprole a 62,5 g i.a. 100 kg-1 de sementes (Dermacor® 0,1 L 100 kg-1 de sementes); ciantraniliprole a 120 g i.a. 100 kg-1 de sementes (Fortenza 600 FS® 0,2 L 100 kg-1 de sementes); fipronil mais piraclostrobina e tio-fanato-metílico 50 + 5 + 45 g i.a. 100 kg-1 de sementes (Standak Top® 0,2 L 100 kg-1 de sementes) e um tratamento controle. O experimento foi conduzido em uma vegetação. Dentre todos os tratamentos, os inseticidas do grupo químico das diamidas (clorantraniliprole e ciantraniliprole) apresentaram os melhores resultados, com consumo inferior pelas lagartas das folhas tratadas e maior eficiência de controle deste inseto. Foi constatado que o tratamento de sementes é uma alternativa viável para o controle de S. frugiperda no início do desenvolvimento da cultura, quando a lagarta apresenta o comportamento de cortar as plântulas e/ou consumir área foliar, ocasionando uma redução da população de plantas e uma consequente perda de produtividade.(AU)

Herbicide selectivity in pre-sprouted seedlings of 'CTC14' sugarcane / Seletividade de herbicidas em mudas pré-brotadas de cana-de-açúcar 'CTC14'

A new sugarcane planting system, using pre-sprouted seedlings (PSS) to replace sugarcane stem fragments, substantiates the hypothesis of this study that there might be seedling toxicity by herbicides that are sprayed at pre-emergence in traditional systems. Therefore, the aim of this paper was to study the selectivity of herbicides applied at pre-planting in PSS. A field experiment was conducted in a randomized block design, using seven treatments and four replications. Herbicides were sprayed and, 24 hours later, the seedlings were planted. At the beggining of seedling development, all herbicide treatments showed phytotoxicity, but the symptoms decreased with the growth and development of seedlings, with no difference in height, stem diameter, number of leaves, quantum efficiency of PSII (Fv/Fm) and dry matter of plants between treatments. There was also no significant difference in the yield and technological characteristics of stems. All herbicides used were selective to sugarcane seedlings when applied at pre-planting in the PSS system.(AU)

Um novo sistema de plantio de cana-de-açúcar, utilizando mudas pré-brotadas (MPB) em substituição aos fragmentos de colmos de cana, fundamenta a hipótese deste trabalho de que poderá haver intoxicação nas mudas pelos herbicidas aplicados na pré-emergência em sistemas tradicionais. Portanto, objetivou-se neste estudo verificar a seletividade de tratamentos herbicidas aplicados em pré-plantio de MPB. O experimento foi realizado a campo, em blocos randomizados, utilizando sete tratamentos em quatro amostras replicadas. Foi realizada a pulverização dos herbicidas e, após 24 horas, o plantio das mudas. No início do desenvolvimento das mudas, todos os tratamentos com herbicida causaram fitotoxicidade, mas com o crescimento e desenvolvimento das mudas, os sintomas foram diminuindo, não havendo diferença entre os tratamentos quanto à altura, o diâmetro de colmos, o número de folhas, a eficiência quântica do FII (Fv/Fm) e a matéria seca das plantas. Também não houve diferença significativa na produtividade e nas características tecnológicas dos colmos. Todos os herbicidas utilizados foram seletivos às mudas de cana-de-açúcar no sistema MPB quando aplicados no pré-plantio.(AU)