ABSTRACT Lima bean plants showing mosaic and leaf distortion symptoms, similar to those induced by viruses, were observed in several production areas in the states of Ceará and Piauí, Northeastern Brazil. The aim of this study was to identify RNA genome viruses that infect lima bean. Field research was conducted from 2017 to 2018. Fifty-five symptomatic samples were randomly collected from seven properties in five municipalities and tested by RT-PCR and DNA sequencing with specific or universal primers for two viruses and two virus groups. Four virus species were identified: cucumber mosaic virus (CMV), cowpea mild mottle virus (CPMMV), cowpea aphid-borne mosaic virus (CABMV) and cowpea severe mosaic virus (CPSMV), which had infection levels of 21.8, 52.7, 47.2, and 1.8%, respectively, as well as double and triple infections. The CMV isolates belonged to subgroup IA. The CPMMV isolates had high nucleotide identity with CPMMV isolates from Brazil, USA and Mexico. The CABMV isolates showed moderate nucleotide identity with Brazilian isolates. Only one sample was infected with CPSMV. This is the first record of CPMMV and CPSMV naturally infecting lima bean. Approaches to virus control are discussed.

The main objectives of this work were to isolate and identify the causal agents of sudden death syndrome (SDS) from samples collected in different Argentinean localities, to quantify its incidence, and to estimate yield losses. Two hundred and fifteen roots from plants with typical SDS foliar symptoms were analyzed. In order to perform pathogenicity tests, two bioassays were conducted in the greenhouse. Yield losses were estimated in a field trial located in Pergamino by quantification and comparison of yield of paired samples. Thirty-six percent of total roots (78 roots) presented signs of Fusarium, compatible with signs caused by SDS. Morphological studies allowed the identification of 35 isolates as F. tucumaniae and 18 as F. virguliforme. Other eight isolates could not be identified. All isolates that were inoculated reproduced typical SDS foliar symptoms. Significant differences were observed between healthy and diseased plants for 1000-grain weight and between potential and real yield (p<0.05). Average yield loss was 1514 kg/ha (range 192-3770 kg/ha). These results corroborated the distribution and predominance of F. tucumaniae and F. viguliforme in the area under study and its destructive potential.

Los objetivos de este trabajo fueron aislar e identificar los agentes causales del síndrome de la muerte súbita (SMS) en muestras provenientes de diferentes localidades de Argentina, y cuantificar la incidencia de la enfermedad y los daños causados a campo en el rendimiento. Se analizaron 215 raíces provenientes de plantas con síntoma foliares típicos de SMS para el aislamiento e identificación de los agentes causales. Para realizar las pruebas de patogenicidad se efectuaron dos bioensayos en invernáculo. Los daños fueron estimados en un ensayo a campo situado en Pergamino a través de la cuantificación del rendimiento de muestras apareadas. El 36% (78 raíces) de las raíces presentó signos de Fusarium, compatibles con los causantes de SMS. Los estudios morfológicos realizados permitieron identificar 35 aislamientos como F. tucumaniae y 18, como F. virguliforme. Otros ocho aislamientos no pudieron identificarse. Todos los aislamientos inoculados reprodujeron los síntomas foliares típicos de SMS. Se observaron diferencias entre el peso de mil granos de plantas sanas y de plantas enfermas y entre el rendimiento potencial y el real (p<0,05). Los daños promedio fueron de 1514 kg/ha (rango 192-3770 kg/ha). Los resultados obtenidos corroboraron la distribución y predominio de F. tucumaniae y F. viguliforme en el área estudiada y su potencial destructivo.

Myracrodruon urundeuva Fr. All. (Anacardiaceae) é uma espécie arbórea nativa que apresenta excelentes propriedades físicas, químicas e biológicas. Entretanto, devido à exploração predatória, está na lista oficial das espécies brasileiras ameaçadas de extinção. Este trabalho teve como objetivo estudar a germinação das sementes de M. urundeuva sob diferentes substratos e regimes de temperatura. O delineamento experimental adotado foi o inteiramente casualizado, em arranjo fatorial 8 x 7 (oito substratos - entre e sobre: papel mata-borrão, areia, vermiculita e pó de coco; sete temperaturas: 25, 27, 30, 35, 20-27, 20-30 e 20-35 ºC), com quatro repetições de 25 sementes cada. Avaliaram-se as seguintes características: germinação (%), primeira contagem (%), índice de velocidade de germinação, tempo médio de germinação (dias) e comprimento (cm) do hipocótilo e da raiz primária. Nas temperaturas constantes ocorreram os tempos médios menores de germinação de sementes e desenvolvimento maior do hipocótilo. As temperaturas de 25 e 27 ºC proporcionaram às sementes resultados satisfatórios de germinação em todos os substratos testados, com exceção do substrato entre papel a 27 ºC. Os substratos vermiculita e pó de coco permitiram bom desempenho germinativo e não exigiram reumedecimento diário, mostrando-se adequados para a avaliação da qualidade fisiológica de sementes de M. urundeuva.

Myracrodruon urundeuva Fr. All. (Anacardiaceae) is a native tree specie with excellent physical, chemical and biological properties. However, due to predatory exploration, it is in the official list of Brazilian species threatened with extinction. This work aimed at studying the germination of M. urundeuva seeds in different conditions of substrate and temperature regime. The experiment was a completely randomized design in a 8 x 7 factorial arrangement (7 temperatures 25, 27, 30, 35, 20-27, 20-30 and 20-35ºC; and 8 substrates - sowing in and on: blotting paper, sand, vermiculite and coconut fiber) with four replications with 25 seeds. The following parameters were analyzed: germination (%), first germination count (%), germination speed index, average time of germination (days), and length (cm) of hipocotyl and primary root. Constant temperatures gave the shortest average time of seed germination and favored hipocotyl development. The best results for germination were obtained at 25 and 27ºC in all substrates, except for sowing in between blotting paper at 27ºC. The vermiculite and coconut fiber substrates allowed satisfactory germinative performance and did not require daily remoisten, proving to be suitable for the evaluation of the physiological quality of M. urundeuva seeds.