New and Emerging Disease Threats to Forest Plantations in Sarawak Borneo, Malaysia

Abstract

The planted forest area in Sarawak is the largest planted forest in Malaysia, which has been developed since 1997 to sustain the decline in the production of natural forests. As of December 2021, the total area of plantation forests reached 551,704 hectares (ha), dominated by fast-growing exotic species mainly Acacia species (55%), Falcataria moluccana (15%) and Eucalyptus (14%). The study showed Acacia was infected with red root rot disease of Ganoderma philippii and brown root rot of Phellinus noxius, Ceratocystis wilt disease caused by Ceratocystis. fimbriata sensu stricto (s.s) complex and pink disease caused by Erythricium salmonicolor, while F. moluccana was infected by gall disease namely Uromycladium falcatarium. Eucalyptus pellita diseases were infected namely by G. philippii red root rot disease, stem canker disease caused by Botryosphaeriaceae pathogen and bacterial wild disease caused by Ralstonia solanacearum. Ceratocystis wilt disease of Acacia mangium shows disease incidence (DI) accounted at 68% (serious) as compared with other diseases observed in this study. This will be the first baseline study that is conducted to observe and assess the diversity of the present, new and emerging pathogens and the damage they cause to exotic planted species of Sarawak.

Evaluation of Fungicides as Protective and Curative Treatments against Canker Disease of Eucalyptus urograndis Caused by Chrysoporthe deuterocubensis in Malaysia

“…Grimes (batai), Fabaceae (alt. Leguminosae), and Eucalyptus pellita F. Muell [3]. Although A. mangium is the dominant species among the three, E. pellita and its hybrids are being planted more lately due to the reduced volume production of A. mangium following their rapid destructive stem-wilt canker disease caused by Ceratocystis spp.…”

“…ex Benth [5]. While a study in 2019 characterised the disease as having poor virulence and that the risk of virulence may increase over successive rotations, reports of Ceratocystis disease incidence in Malaysia remain relatively low at 7.5% [3], reflecting the limited critical evaluation of this disease in the country, especially in Sarawak.…”

“…Recently, two Chrysoporthe species that have been found to infect Eucalyptus tree plantations worldwide were identified in Malaysia, namely Chrysoporthe deuterocubensis and its sibling species Chrysoporthe cubensis [19,20,23]. The basal cankers caused by C. deuterocubensis can spread several metres up the stem and are lethal to young and juvenile trees [3]. Based on a pathogenicity test on C. deuterocubensis isolated in Sabah, Malaysia, the species was pathogenic to E. grandis trees and Eucalyptus deglupta [21].…”