Abstract:Desenvolveu-se uma técnica de detecção rápida de Ceratocystis fimbriata em lenho de eucalipto (Eucalyptus spp.) infetado, visualizando-se clamidósporos (aleuroconídios) ao microscópio ótico comum, em vasos do xilema, medula e raios medulares, a partir de cortes histopatológicos à mão livre, feitos com lâmina de barbear, ao microscópio estereoscópico. O tempo médio gasto para a detecção do patógeno, do corte histopatológico tangencial à total visualização dos clamidósporos ao microscópio ótico comum, foi de 3,5… Show more
“…Later, in the radial direction, the fungus causes death of portions of the vascular cambium, phloem and phelloderm (Ferreira et al 2006). As the disease progresses, there is formation of aleuroconidia, which accumulate inside the vessels (Ferreira et al 2005). Free aleuroconidia also indicate that translocation along the vessels is possible.…”
In this study, we determined the effects of Ceratocystis fimbriata wilt on volumetric growth and cellulose pulp yield of eucalyptus. Sevenyear-old healthy and infected trees were separated into different classes of severity, and the individual volume of each whole tree with bark was determined. Volumetric losses were found regardless of the class of disease severity, resulting in reduction in volumetric growth of the trees from 65% to 87%, depending on the infection level. Two approaches were used for evaluating the effects of the disease on cellulose pulp yield: (i) evaluation of wood basic density and chemical composition, contents of ethanol/toluene extractives and Klason lignin, and the alkaline load and screen yield across Kraft pulping to kappa number 18 AE 0.5 for both healthy and discoloured materials; (ii) determination of the alkaline load and yield across Kraft pulping to kappa number 18 AE 0.5 of woods with different levels of discoloration (0, 25, 50, 75 and 100% of discoloured wood). Discoloured wood presented lower basic density, higher ethanol/toluene extractives and Klason lignin, higher alkaline load and lower pulp screened yield at kappa number 18 AE 0.5 compared with the healthy ones. Increasing the fraction of infected wood in chip furnishes resulted in proportionally increased alkaline load demand and decreased screen yields. Adding 50% of infected wood in the chip furnish resulted in 23.8% increase in the alkali load and 13.7% reduction in the pulp screen yield at kappa number 18 AE 0.5. The results obtained have proved that the disease reduces volumetric growth, increases wood consumption and reduces yield in eucalyptus pulp production.
“…Later, in the radial direction, the fungus causes death of portions of the vascular cambium, phloem and phelloderm (Ferreira et al 2006). As the disease progresses, there is formation of aleuroconidia, which accumulate inside the vessels (Ferreira et al 2005). Free aleuroconidia also indicate that translocation along the vessels is possible.…”
In this study, we determined the effects of Ceratocystis fimbriata wilt on volumetric growth and cellulose pulp yield of eucalyptus. Sevenyear-old healthy and infected trees were separated into different classes of severity, and the individual volume of each whole tree with bark was determined. Volumetric losses were found regardless of the class of disease severity, resulting in reduction in volumetric growth of the trees from 65% to 87%, depending on the infection level. Two approaches were used for evaluating the effects of the disease on cellulose pulp yield: (i) evaluation of wood basic density and chemical composition, contents of ethanol/toluene extractives and Klason lignin, and the alkaline load and screen yield across Kraft pulping to kappa number 18 AE 0.5 for both healthy and discoloured materials; (ii) determination of the alkaline load and yield across Kraft pulping to kappa number 18 AE 0.5 of woods with different levels of discoloration (0, 25, 50, 75 and 100% of discoloured wood). Discoloured wood presented lower basic density, higher ethanol/toluene extractives and Klason lignin, higher alkaline load and lower pulp screened yield at kappa number 18 AE 0.5 compared with the healthy ones. Increasing the fraction of infected wood in chip furnishes resulted in proportionally increased alkaline load demand and decreased screen yields. Adding 50% of infected wood in the chip furnish resulted in 23.8% increase in the alkali load and 13.7% reduction in the pulp screen yield at kappa number 18 AE 0.5. The results obtained have proved that the disease reduces volumetric growth, increases wood consumption and reduces yield in eucalyptus pulp production.
“…There is also the technique of rapid detection of Ceratocystis spp. on infected stems by visualizing chlamydospores in the xylem vessels, pith and medullary rays from histopathological sections on an optical microscope (Ferreira et al, 2005). However, to perform these tests it is necessary to cut the stem in search of the lesion in dead plants.…”
Ceratocystis wilt is a lethal disease to several hosts. This study tested the isolation of Ceratocystis spp. from the leaf blade of cacao and other hosts showing yellowing and the isolates pathogenicity to their hosts. Leaves with yellowished and/or darkened areas were disinfested and placed between slices of unripe cacao pods, like a sandwich, in a BOD chamber (25 o C), for four days. Ascospores were transferred to Petri dishes containing PDA and their colonies were preserved. The presence of C. cacaofunesta in the leaf blade of cacao tree; C. paradoxa in coconut palm; and C. fimbriata in eucalyptus, rubber, soursop, custard-apple trees and coffee plants were confirmed. To test the isolates pathogenicity, culture discs or droplets of inoculum suspensions (3 × 10 4 i.u./mL) were applied in two points on leaves of each host, with and without wound, and evaluated in four to seven days. Chlorosis, lesions, mycelia and perithecia development were observed in the midrib and on blades of inoculated leaves. Therefore, an early method of detection of Ceratocystis spp. as well as another method to evaluate pathogenicity to various hosts using whole leaves of these hosts were described in this paper.
“…Entre elas, peritécios com pescoços longos e com hifas ostiolares (Figura 2a, b); ascósporos com a aparência de chapéu (Figura 2c); endoconídios cilíndricos, unicelulares, hialinos e catenulados produzidos em endoconidióforos, também cilíndricos, longos e hialinos (Figura 2d, e); além de clamidósporos castanhos, globosos a piriformes ocorrendo tanto isoladamente, quanto em cadeias curtas (Figura 2f) (Morgan-Jones, 1967;Hanlin, 1990). Em exames histológicos realizados em materiais naturalou artificialmente infectados, adotando uma metodologia simples utilizada na diagnose da doença em outros hospedeiros (Ferreira et al, 2005), foram observados hifas e clamidósporos do fungo no interior dos vasos do xilema (Figura 2f).…”
Ceratocystis wilt, a new disease of the cupuassu tree, in Brazil. The cupuassu tree (Theobroma grandiflorum), native of the Amazon region, is cultivated mainly in the states of Para, Amazonas, Acre and Bahia, Brazil. In Bahia, it has been planted in the same municipalities were cacao is grown, especially, in the region known as Baixo Sul. During fitossanitary inspections carried out in one area at the Cacao Research Center (CEPEC), in Ilheus, BA, cultivated with cupuassu, trees showing symptoms of wilting, chlorosis and leaf drying, in addition to canker and necrosis of the stem, were observed. Ceratocystis fimbriata was the fungus, predominately, isolated in PDA medium in all the attempts using necrotic tissues obtained from the stem. Histopathological studies, done at the optical microscope, showed the presence of mycelia and chlamydospores of the fungus in the xylem vessels. Three-and 8-month-old cacao and cupuassu seedlings inoculated with the fungus started exhibiting the disease symptoms 20 and 40 days later, respectively. The fungus was re-isolated from inoculated plants in all the attempts. This is the first record of ceratocystis wilt disease in cupuassu tree.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.