Abstract Brown leaf spot disease, caused by the fungus Ragnhildiana diffusa, is responsible for losses in pecan orchards and quantification is essential in order to conduct epidemiological studies to establish levels of productivity losses, and assess control strategies. Therefore, the aim of this study was to develop and validate a diagrammatic scale for assessing the severity of brown leaf spot in pecan. 240 symptomatic leaflets were collected from adult trees in Anta Gorda, in the Brazilian state of Rio Grande do Sul, and used to assess the current percentage severity of the disease. The scale was based on the minimum and maximum observed severity of the disease, with six graduations defined according to the Weber-Fechner Visual Stimulus Law. The scale therefore consisted of eight levels (1.5, 4.6, 10.6, 17.3, 39.5, 65.1, 77.5, and 98%). The estimates of eight evaluators provided a basis for validating the scale. They made estimates of disease severity on 40 symptomatic digitalized pecan leaflets first, without using the scale and then referring to it. The scale provided greater precision, accuracy, and reproducibility of estimates and should result in more reliable epidemiological studies.

Muitas são as lacunas referentes à avaliação do potencial fisiológico de sementes de espécies olerícolas, dentre essas a salsa. Nesse contexto, o teste de envelhecimento acelerado é reconhecido como um dos mais difundidos para a avaliação do vigor das sementes de várias espécies cultivadas, sendo capaz de proporcionar informações com alto grau de consistência. Assim, o presente trabalho teve por objetivo estudar a metodologia do teste de envelhecimento acelerado para avaliação do potencial fisiológico de sementes de salsa, bem como, verificar a possibilidade do uso de soluções de NaCl como alternativas para o controle da velocidade e intensidade de absorção de água pelas sementes durante a realização do teste, sem reduzir sua sensibilidade. Quatro lotes de sementes foram submetidos aos testes de germinação, emergência de plântulas e envelhecimento acelerado, empregando-se os períodos de envelhecimento de 48, 72 e 96 h (tradicional e com o uso de soluções de NaCl). A utilização de solução não saturada de NaCl diminui a velocidade de absorção de água pelas sementes de salsa durante o teste de envelhecimento acelerado, acarretando redução da taxa de deterioração e resultados mais uniformes. A exposição por 48 h, utilizando solução salina saturada constitui opção promissora para a avaliação do potencial fisiológico das sementes.

There are many gaps for the assessment of seed vigor in vegetable crops, among these the parsley. In this context, the accelerated aging test is recognized as one of the most widely used to evaluate seed physiological potential of various crop species, being able to provide information with a high degree of consistency. Thus, the objective of the present study was to evaluate the methodology of accelerated aging test to check parsley seed vigor, as well as verify the possibility of using NaCl solutions as an alternative to control seed water uptake during the aging period without reducing test sensitivity. Four lots of parsley seeds were tested for germination, seedling emergence, and accelerated aging for 48, 72 and 96 h (traditional and NaCl solutions). The use of NaCl solutions reduces water uptake by parsley seeds during the accelerated aging test, resulting in less pronounced and drastic deterioration rates and more uniform results. The exposure of the P. sativum seeds for a period of 48 h is a promising option for the evaluation of parsley seed vigor by the accelerated aging test.

A patogenicidade e o biocontrole de Fusarium oxysporum (F1s, F3s e F4s) e F. proliferatum (F2s) por Trichoderma koningiopsis (T1s e T3s), T. tomentosum (T2s e T4s) e T. asperellum (T5s) foi avaliada. Testes in vitro, confrontação direta, e in vivo, por inoculação de substrato com Fusarium spp. e Trichoderma spp., isolados e combinados, foram conduzidos em condições controladas. A habilidade de Fusarium spp. causarem damping off em plântulas de soja, cv. ‘FT-Estrela’, foi avaliada in vivo em tratamentos que receberam apenas inóculo de Fusarium spp. isolados de Trichoderma spp. promoveram o crescimento de raiz e incrementaram o peso fresco e seco de plântulas de soja. Os isolados de Fusarium spp. F1s e F4s foram os mais agressivos, com 100 e 75% de damping off, respectivamente. Algumas combinações com Trichoderma spp. potencializaram a patogenicidade de F1s e F3s, com 100 e 75% de damping off, respectivamente. Os isolados de Trichoderma spp. podem controlar Fusarium spp. avaliados neste estudo.

Pathogenicity and biocontrol of Fusarium oxysporum (F1s, F3s and F4s) and F. proliferatum (F2s) by Trichoderma koningiopsis (T1s and T3s), T. tomentosum (T2s and T4s) and T. asperellum (T5s) was evaluated. In vitro tests, direct confrontation, and in vivo, substrate inoculation with Fusarium spp. and Trichoderma spp., isolated or combined, were conducted under controlled conditions. The ability of Fusarium spp. cause damping off in seedlings of soybean cv. ‘FT-Estrela’, was evaluated in vivo in treatments that received only inoculum of Fusarium spp. Trichoderma spp. isolates promoted root growth and increased the fresh and dry weight of soybean seedlings. Fusarium spp. isolates F1s and F4s were the most aggressive, with 100 and 75% of damping off, respectively. Some combinations with Trichoderma spp. potentiated the pathogenicity of F1s and F3s, with 100 and 75% of damping off, respectively. The Trichoderma spp. can control Fusarium spp. evaluated in this study.