Resistance of Bt transgenic maize to lesser cornstalk borer (Lepidoptera: Pyralidae).

To determine if Bt maize seedlings are protected against lesser cornstalk borer damage, Bt hybrids at the 3 and 4 leaf stages were tested under temperatures between 20-32oC and artificial infestation. A high level of resistance was reported in all Bt maize as expressed by larval survival, larval weight, damage score, and number of surviving plants. All Bt maize protected plants against lesser cornstalk borer damage. Also, the resistance present in the Bt maize was not affected by daytime temperature.

Toxicity of pyrethroids and other insecticides against susceptible and resistant tobacco budworm larvae and synergism by chlordimeform.

1987

Tobacco budworm resistance to pyrethroids: resistance spectra, synergists, and substitute insecticides.

1988

Efficacy and economic returns from various insecticide combinations applied for tobacco budworm control in the Brazos River Valley.

A field efficacy evaluation revealed significant differences in efficacy among a few of the numerous insecticides or combinations of insecticides applied for Heliothis spp. control. An increasing proportion of made up this field population during the test period. Partial budgeting revealed that the net returns from applying any treatment were directly proportional to the resulting yield obtained from that treatment.

Tobacco budworm control without resistance: is it possible?

1986

Identification of sources of resistance to anthracnose stalk rot in maize.

O uso de cultivares resistentes é a principal medida para o manejo da antracnose do colmo em milho. Neste trabalho, objetivou-se identificar linhagens com níveis de resistência à antracnose do colmo, similar ao híbrido 2B710, considerado resistente. Dois experimentos foram conduzidos na Embrapa Milho e Sorgo. No primeiro experimento, foram avaliados 234 linhagens e os híbridos BRS1010 (suscetível) e 2B710 (resistente). Foi realizada inoculação artificial com um isolado de C. graminicola, na fase de pré-pendoamento e, após 30 dias, foi realizada a avaliação da severidade da antracnose no colmo. O segundo experimento foi conduzido com 48 linhagens e os híbridos inoculados com dois isolados de C. graminicola. No primeiro experimento, os genótipos formaram oito grupos com base na severidade da doença e as linhagens do último grupo foram consideradas as mais resistentes, incluindo o híbrido 2B710, em que os genótipos apresentaram valores de severidade entre 11,50 a 23%. No segundo experimento, houve interação entre os fatores linhagens e isolados e, de modo geral, as linhagens apresentaram a mesma tendência de reação obtida no primeiro experimento, no entanto, a severidade da doença foi maior para a maioria das linhagens, mesmo quando utilizado o outro isolado. Com isso, foi possível realizar a seleção de linhagens com bons níveis de resistência, as quais podem ser utilizadas em programas de melhoramento, em estudos de herança, desenvolvimento de híbridos e identificação de marcadores moleculares, associados com resistência à antracnose do colmo.

Study of root architecture by overexpressing the maize Rtcs gene in tobacco.

2016

Overexpression and characterization of rice Phosphorus-Starvation Tolerance 1 gene and its sorghum and maize homologs in transgenic tobacco.

2016

First report of Phaeocytostroma ambiguum causing maize stalk Rot in Brazil.

2016

Combined effects of soil biotic and abiotic factors, influenced by sewage sludge incorporation, on the incidence of corn stalk rot.

Abstract: The objectives of this study were to evaluate the combined effects of soil bioticand abiotic factors on the incidence of Fusarium corn stalk rot, during four annual incorporations of two typesofsewagesludge intosoil ina 5-years field assay under tropical conditions and topredict the effectsof these variables on the disease. For each type of sewage sludge, the following treatments were included: control with mineral fertilization recommended for corn; control without fertilization; sewage sludge based on the nitrogen concentration that provided the same amount of nitrogen as in the mineral fertilizer treatment; and sewage sludge that provided two, four and eight times the nitrogen concentration recommended for corn. Increasing dosages of both types of sewage sludge incorporated into soil resulted in increased corn stalk rot incidence, being negatively correlated with corn yield. A global analysis highlighted the effect of the year of the experiment, followed by the sewage sludge dosages. The type of sewage sludge did not affect the disease incidence. Amultiple logistic model using a stepwise procedure was fitted based on the selection of a model that included the three explanatory parameters for disease incidence: electrical conductivity, magnesium and Fusarium population. In the selected model, the probability of higher disease incidence increased with an increase of these three explanatory parameters. When the explanatory parameters were compared, electrical conductivity presented a dominant effect and was the main variable to predict the probability distribution curves of Fusarium corn stalk rot, after sewage sludge application into the soil.

Reação de genótipos de girassol à podridão branca (sclerotinia sclerotiorum) em condições de campo, na safrinha 2014.

RESUMO: O objetivo do presente trabalho foi avaliar a reação de genótipos de girassol à podridão branca, causada por Sclerotinia sclerotiorum, no colo e no capítulo, em condições de campo. Dezoito cultivares de girassol foram avaliadas, em experimento implantado em maio de 2014, em Mauá da Serra, PR, em condições de infecção natural do fungo. A avaliação das plantas indicou que a doença foi favorecida pelas condições climáticas de baixa temperatura e alta umidade, ocorrida na região na época de condução do experimento. Todos os genótipos de girassol avaliados foram suscetíveis a S. sclerotiorum. ABSTRACT: The objective of the present work was to evaluate the reaction of sunflower genotypes to Sclerotinia stalk and head rot, caused by Sclerotinia esclerotiorum. Eighteen cultivars were evaluated in a field experiments sowed in May 2014, in Maua da Serra, PR, Brazil, under natural infection in the field. The evaluation of the plants indicated that the disease was favored by the climatic conditions of low temperature and high humidity, which occurred in the region during the time of conducting the experiment. All sunflower genotypes tested are susceptible to Sclerotinia stalk and/or head rot.