Survey, Identification, and Pathogenicity of Ceratocystis fimbriata Complex Associated with Wilt Disease on Acacia mangium in Malaysia

Ceratocystis wilt disease surveys were conducted in three selected Malaysian Acacia mangium plantations. These completed surveys revealed the occurrence of the wilt disease, with the incidence of infection ranging from 7.5% to 13.6%. Signs of wood-boring insects, bark peeling due to squirrel activity, and pruning wounds were often associated with this disease. The fungus most frequently isolated from the diseased trees was the Ceratocystis fungus. The analysis on the morphological characteristics has identified the fungus as Ceratocystis fimbriata complex. Phylogenetic analysis based on the sequences of the ITS, and concatenated sequences of EF1α-βT regions grouped the isolates within the C. fimbriata sensu stricto, in comparison to other C. fimbriata isolates. Pathogenicity tests were conducted on six to nine-month-old healthy A. mangium seedlings by inoculating these seedlings with eight out of the 16 isolates. The results demonstrated that all the isolates were pathogenic, with mortality beginning as early as two weeks after inoculation. However, an ANOVA test indicated a significant difference between the pathogenicity levels among the fungal isolates. The results also showed that pathogen aggressiveness was not correlated with geographical origin. A host range test was also conducted by using C. fimbriata SSB3 and FRIM1162 isolates against several forest plantation species. The findings suggested that only A. mangium was susceptible to C. fimbriata. The other species remained healthy with no symptoms of infection even after seven weeks of treatment, as compared to the A. mangium species, where between 38 to 60% of the inoculated plants had died. This study provides new information on the status of Ceratocystis wilt disease, especially on the occurrence and effects on A. mangium plantation, by giving insights on how to control and manage this ferocious plant pathogen in the future.

Preliminary study of canker disease for development of urban tree health standard in Malaysia

Canker disease (CD) mainly infected trees planted in urban areas in Malaysia. This disease is caused by several plant pathogens and may cause tree death and tree failure. The aims of this study are to identify tree species which are susceptible to canker diseases and to identify the causal agents especially plant pathogens of the disease. To perform the study, a survey on planted trees in several urban parks and sites in Malaysia were conducted. In this study, the Canker Disease (CD) assessment procedure was developed and modified from Thousand Cankers Disease Survey Guidelines by the United State Department of Agriculture (USDA). Later, the assessment procedure was improved based on surveys in the ground to fit and get the best quality of data from the observations. As a result, several canker diseases were identified on twenty-three (23) trees, the species were, Acacia sp, Bucida molineti, Cinnamomum iners, Citrus sp, Eucalyptus urograndis, Eucalyptus camaldulensis, Eucalyptus sp, Khaya grandifoliola, Mangifera indica, Manilkara zapota, Mimusops elengi, Peltophorum indicus, Samanea saman, Swietenia macrophylla, Swietenia spicifera, Tabebuia argentea, Terminalia catappa, Terminalia mantaly, Araucaria heterophylla, Casuarina equisetifolia, Gymnostoma sumatrana and Polyalthia longifolia. Based on symptom development the canker diseases known as Sphaeropsis canker, Cryphonectria canker, Chrysoporthe canker, Biscogniauxia canker, Hypoxylon canker, Cypress canker, Nectria canker, Ceratocystis Wilt, Pink disease, and Slime flux disease. This study can be the starting point in developing the Canker Disease (CD) Assessment Standard in Malaysia. It is important for Malaysia to have a Canker Disease (CD) Assessment Standard in order to become a guideline for future study or research that specifies canker disease towards common trees planted in Malaysia especially the urban areas.

PROPERTIES OF TEAK WOOD INFECTED BY Ceratocystis fimbriata

In Brazil, the growth of Tectona grandis (teak) plantations is accompanied by an increased incidence of Ceratocystis wilt, a fungal disease that colonizes the vascular system of such tree. The objective of this work was to evaluate the properties of teak wood infected with Ceratocystis fimbriata at different radial positions. Ten 17-year-old trees (five infected and five healthy) were collected. A disk was removed from the base of each tree to determine Janka hardness, basic density, anatomical analysis, colorimetric parameters in the CIEL*a*b* system and sodium hydroxide solubility (NaOH). There were no significant differences for radial position and health for basic density and Janka hardness of the wood, with mean values of 0.488 g.cm3 and 58.66 MPa, respectively. The deposition of dark compounds was observed inside the parenchyma cells and fibers, as well as the formation of tyloses in the sapwood. Yellow pigment was predominant in the color formation of teak wood, which was influenced by radial position, with the sapwood being lighter. Regarding C. fimbriata infection, the color change was more evident in sapwood. Conversely, the NaOH solubility was lower for the sapwood attacked by the fungus. In conclusion, the changes in teak wood infected by C. fimbriata are visual and the anatomical structures do not deteriorate.

Vascular Trouble

This chapter looks at two diseases affecting the vascular system of the cacao tree: vascular streak dieback, caused by the fungus Ceratobasidium theobromae, and wilt disease, caused by the fungus Ceratocystis cacaofunesta. Both diseases are considered as serious threats to cacao production and their impact has already been considerable and severe. Vascular streak dieback nearly destroyed the cacao industry in Papua New Guinea and is mercifully restricted to Indonesia, Malaysia, and South-East Asia, while Ceratocystis wilt has been reported in several countries in South and Central America, where it has caused substantial crop losses. The chapter examines the research being undertaken to better understand these diseases and how best to tackle them.