Economic injury level of Helicoverpa armigera on bean Phaseolus vulgaris L. seedlings

A lagarta Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) chegou ao Brasil em 2012 e vem causando prejuízos severos aos agricultores, especialmente nas culturas do algodão, feijão, milho, soja e tomate nas regiões Norte, Nordeste e Centro-Oeste. Pouco se conhece sobre seus danos às culturas no país e o feijoeiro é uma das culturas menos estudadas dentre as citadas. Portanto, esse trabalho objetivou-se avaliar o nível de dano causado pela lagarta H. armigera de 3º ínstar em plântulas de feijão cv. BRS-Estilo. O ensaio foi semeado em 10/04/2014, em Ribeirão Preto, SP, com espaçamento de 0,5 m e 12 plantas por metro. Em um delineamento em blocos casualizados, as infestações (18/04) de 0 (testemunha), 0,1, 0,2, 0,5 e 1 lagarta por planta foram repetidas quatro vezes, em parcelas de 0,5 m2 cercadas por barreias de PVC de 20 cm de altura e com bordadura de 1 m. Após 1, 3, 7 e 14 dias após a infestação foi avaliada a porcentagem de desfolha. A porcentagem média de desfolha foi proporcional à densidade de lagartas. O nível de dano de lagartas de 3º ínstar de H. armigera é de 1,4 lagartas por planta e, dessa forma, o nível de controle deve ser de 0,7 lagartas por planta de feijoeiro

Potential of entomopathogenic fungi to control insect pests and disease at lettuce and arugula crops

The lettuce (Lactuca sativa L.) (Asteraceae) and arugula (Eruca sativa Miller) (Brassicaceae) crops are attacked by various pests and diseases, but the control is usually done with agrochemicals. We evaluate the control of pests and diseases by systematic applications of the entomopathogenic fungi strains Metarhizium anisopliae IBCB425 and Beauveria bassiana IBCB66 both 300g c.p. in the planting groove and 200 g c.p. ha-1 on the foliage, in weekly applications at lettuce and arugula crops planted in association. For the evaluation of pests and diseases, 15 plants were evaluated at random in three beds per treatment. In the lettuce crop occurred the presence of aphids (Myzus persicae Hemiptera:Aphididae), whiteflies (Bemisia tabaci Hemiptera: Aleyrodidae), thrips (Frankliniella schultzei Thysanoptera:Thripidae), leafhoppers Agallia albidula (Hemiptera: Cicadellidae) and septoria disease (Septoria lactucae). In the arugula crop the same pests occurred, but with any disease. The fungi B. bassiana and M. anisopliae controlled F. schultzei and S. lactucae at lettuce crop, B. tabaci in both crops, but did not control M. persicae and A. albidula in both crops. The fungus B. bassiana decreased the mean number of leaves per plant and the mean of dry mass weight of arugula plants in relation to the control treatment, but the sample size may have interfered with these results. The two fungi could be used as biological control agents of pests and diseases at lettuce and arugula crops, especially in organic farming

Entomopathogenic fungi on the control of Sphenophorus levis in sugarcane crop

Brazil is the largest producer of sugarcane crop in the world,but its production can be highly affected by the pest Sphenophorus levis. The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana can be used for the control of this pest, but are not always effective in the field, lacking information on application methods, doses and formulations. We evaluate the efficacy of M. anisopliae IBCB 425 and B.bassiana IBCB 66 in controlling S. levis and other soil pests at sugarcane crop. The bioassay was conducted in a split plot design, where each of the 4 treatments were repeated 5 times and distributed over an area of 5.000 m2. The treatments for both fungi consisted of: Wettable powder (WP) formulation 225 g conidia ha-1, WP formulation 450 g conidia ha-1, granule (GR) formulation 10 Kg ha-1 and Control (no fungal application). WP fungi formulations were applied to the ratoon with a tractor using a ratoon cutter and an pesticide applicator. The GR fungi formulation was manually applied on the ratoons. The evaluations were performed after 21, 60 and 100 days of fungi application. B. Bassiana fungus reduced the pest population but did not differ from the control, however for M. Anisopliae fungus there were significant differences between treatments on damaged stems. The fungus M. anisopliae was effective in controlling S. levis larvae and adults in the field and WP formulation had faster action than the GR, the dose of 225 g conidia ha-1 was enought to reduce S. levis population

Biology and Management of Pest Diabrotica Species in South America

The genus Diabrotica has over 400 described species, the majority of them neotropical. However, only three species of neotropical Diabrotica are considered agricultural pests: D. speciosa, D. balteata, and D. viridula. D. speciosa and D. balteata are polyphagous both as adults and during the larval stage. D. viridula are stenophagous during the larval stage, feeding essentially on maize roots, and polyphagous as adults. The larvae of the three species are pests on maize, but D. speciosa larvae also feed on potatoes and peanuts, while D. balteata larvae feed on beans and peanuts. None of these species express a winter/dry season egg diapause, displaying instead several continuous, latitude-mediated generations per year. This hinders the use of crop rotation as a management tool, although early planting can help in the temperate regions of the distribution of D. speciosa. The parasitoids of adults, Celatoria bosqi and Centistes gasseni, do not exert much control on Diabrotica populations, or show potential for inundative biocontrol plans. Management options are limited to insecticide applications and Bt genetically modified (GM) maize. Other techniques that show promise are products using Beauveria bassiana and Heterorhabditis bacteriophora, semiochemical attractants for monitoring purposes or as toxic baits, and plant resistance.Facultad de Ciencias Naturales y Muse

Comparison of release techniques and parasitism of Trichogramma galloi Zucchi, 1988, in heavy infestations of Diatraea saccharalis (Fabr., 1794), on sugar cane

Estudou-se a atuação de Trichogramma galloi, 1988, em níveis de infestação artificial de ovos de Diatraea saccharalis</i. (Fabr., l 794) prejudiciais à cultura da cana-de-açúcar, comparando-se diferentes técnicas de liberação do parasitóide. Os ensaios foram realizados em canaviais comerciais de Piracicaba e Araras, SP, durante os anos de 1996 a 1998, em diferentes variedades e estágios fonológicos da planta. As técnicas de liberação comparadas foram: l) adultos dispersos na área; 2) adultos em ponto fixo e central na área; 3) pupas aderidas a um cartão, desprotegidas, em ponto fixo; 4) pupas protegidas, de uma idade, em ponto fixo e; 5) pupas protegidas, de 3 idades diferentes, em ponto fixo e central na área. Para se determinarem os níveis de infestação de ovos de D. saccharalis prejudiciais à cultura, foram instalados 3 experimentos em épocas diferentes. A densidade de ovos é fundamental para estudos de infestação de D. saccharalis e de parasitismo de T. galloi, em campo. Põde-se verificar que existiu uma relação diretamente proporcional entre o número de ovos de D. saccharalis, por unidade de área, e a intensidade de infestação em colmos, sendo esta relação influenciada por vários fatores, como a predação de ovos e o clima. A predação mostrou ser diretamente proporcional ao número de ovos por ponto de infestação, chegando a 100% em pontos com grande densidade de ovos. O clima interferiu na eficiência das liberações, sendo os principais parâmetros a temperatura e a precipitação pluviométrica. Por outro lado, o efeito da umidade relativa do ar sobre T. galloi depende da fonologia da cana-de-açúcar. Não existiram diferenças na porcentagem de parasitismo e no tempo de atuação de T. galloi entre as técnicas de liberação por dispersão ou em ponto fixo e central na área, assim corno entre as que utilizaram adultos ou pupas desprotegidas. O tempo de atuação de T. galloi foi sempre de 6 dias, independente da técnica de liberação utilizada, embora o parasitismo tenha sido decrescente com a idade. A proteção de pupas, para a liberação no campo, mostrou ser importante quando as condições climáticas são adversas ao parasitóide. A utilização de pupas com urna idade ou 3 idades diferentes, nos recipientes de liberação, propiciaram a mesma eficiência e tempo de atuação de T. galloi. Existiu uma relação inversamente proporcional entre o número de ovos por ponto de infestação e a porcentagem de parasitismo, a partir de 50 ovos por local de infestação. Os resultados indicaram que os estudos de infestação artificial de D. saccharalis e parasitismo por T. galloi devem utilizar áreas com pontos de infestação com baixa densidade de ovos, os quais podem ser obtidos utilizando-se fêmeas mais velhas, nas gaiolas presas às plantas, por produzirem massas de ovos menores.The performance of Trichogramma galloi Zucchi, 1988 at heavy artificial infestation leveis of Diatraea saccharalis (Fabr., 1794) eggs, on sugar cane, was studied by comparing different parasitoid release techniques. The triais were conducted in commercial cane fields in Piracicaba and Araras, state of São Paulo, from 1996 to 1998 in different sugar cane varieties and phenological stages of the plant. The following release techniques were compared: 1) adults scattered in the area; 2) adults in a fixed central point in the area; 3) exposed pupae attached to a carton in a fixed point; 4) protected pupae of the sarne age in a fixed poínt; and 5) protected pupae of 3 different ages in a fixed central area. ln order to determine the infestation levels of D. saccharalis eggs that cause damage to the crop, three experiments were set up in different periods. The density of eggs is basic for studies on D. saccharalis infestation and T. galloi parasitism in the field. A relationship between the number of D. saccharalis eggs per unit area, and the infestation intensity was observed to be influenced by several factors, such as egg predation and weather. Predation was directly proportional to the number of eggs per infestation site, reaching 100% in large egg clusters. The weather affected the efficiency of the releases, and the main parameters were temperature and rainfall. On the other hand, the effect of the relative humidity on T. galloi depends on the phenology of the sugar cane. No differences were observed in the percentage of parasitism and action period of T. galloi among the release techniques using broadcast form or point sources in an area, as well as among those techniques using either adults or exposed pupae. The action period of T. galloi took always 6 days, regardless of the release technique used, although the parasitism decreased according to the age. Pupae protection for field release was very important when the weather conditions were unfavorable to the parasítoid. The use of pupae at one age or at 3 different ages into the release container provided the sarne efficiency and performance time of T. galloi. A inverse relationship between the number of eggs per infestation site and the parasitism percentage starting with 50 eggs per infestation site occurred. The results indicated that one should use areas ,vith low egg density infestation sites, which can be achieved by using older females in cages attached to the plants, because they produce lesser egg masses