Durian is the favourite fruit in many Southeast Asian countries. It is a prized tree in many mixed gardens and a valuable orchard crop that commands extraordinarily high prices at local and export markets. The value of the worldwide trade in durian is estimated at A$ 3 billion annually. This project will develop strategies to control fruit rot, root rot, patch canker and dieback of durian (Durio zibethinus M.), caused by strains of Phytophthora usually identified as P. palmivora Butl. These diseases cause annual yield losses estimated at 15-30%, and their impact is compounded by locally severe incidences of tree deaths, and storage and transit rots that can destroy entire consignments.
The genus Phytophthora includes pathogens that cause root, stem, foliage, flower and fruit diseases of plants, although the pathogen is generally considered soil-borne. Disease is usually initiated when dormant propagules germinate and release infective zoospores following wetting or temporary flooding. Phytophthora is a poor saprophytic competitor, and the survival of the pathogen in the soil is vulnerable to orchard management practices that stimulate the activity of soil antagonists and reduce the likelihood of ponding. Composts and manures that stimulate the activity of actinomycetes, endospore-forming bacteria and certain fungi are used to reduce the incidence and severity of Phytophthora diseases in crops such as avocado (Stirling, Hayward & Pegg, 1992) and thryptomene (Aryantha, 1997; Aryantha & Guest, 1997). Composts and manures also improve soil drainage, soil fertility and plant growth.
Durian is a tall tree that is amenable to mixed farming systems in the tropics. However, the broad host range of P. palmivora creates a risk of cross-infection between intercrops. The variability of Phytophthora also presents a challenge to plant breeders attempting to incorporate disease resistance into breeding lines, and presents a challenge to quarantine barriers. Consequently, it is imperative to document and understand the host range, geographical distribution and virulence of pathogen isolates from different durian-growing areas.
Australian researchers are world leaders in developing integrated disease management (IDM) strategies, including the use of potassium phosphonate, to control plant diseases. Phosphonates have a remarkably low toxicity to mammals, and are selective for pathogenic Oomycetes such as Phytophthora (Guest et al., 1995). When directly injected into the trunk, phosphonates are extremely effective against Phytophthora diseases of cocoa and avocado (Guest et al. 1994 & 1995). The precise timing and rates of trunk injection are known to be important in determining the translocation and partitioning of phosphonate within the tree, and thus the level of disease control achieved. Thus, the mixed results from preliminary trials with durian suggest that further work on the timing of phosphonate injection in relation to tree phenology is required.
The primary objective of this project is to improve orchard establishment and sustainability, and the consistency of quality fruit supplies to the expanding Asian and Australian durian markets, by developing an integrated management program for orchard and postharvest disease. We will also examine the interaction between losses due to Phytophthora and other major post-harvest pathogens, and will develop strategies to improve fruit quality and prolong fruit life. Key elements of the project will be the development of orchard management practices that are appropriate for small-scale mixed farming systems as well as large orchards, including biological control and the targeted use of trunk-injected fungicides. These control strategies will be based on a thorough understanding of the biological and environmental factors conducive to disease, and will investigate techniques successfully used against Phytophthora diseases of avocado and cocoa. The expected outcome of this project, and the implementation of its recommendations, will be to reduce tree deaths, increase fruit yields and decrease post-harvest fruit losses. Diseases caused by related Phytophthora species also cause significant losses to Australian horticulture, and to the Australian environment. This proposal will address questions that are common to the management of disease in horticultural and natural plant communities.
This proposal builds on work on the control of Phytophthora fruit rot of durian in Thailand using Aliette (Pongpisutta & Sangchote, 1994), research on integrated management of Phytophthora on cocoa in Papua New Guinea (Guest et al. 1994), and biological control of Phytophthora cinnamomi in horticulture (Aryantha & Guest, 1997). A collaboration has already been established between the University of Melbourne, the Northern Territory Department of Primary Industry and Fisheries, the Queensland Department of Primary Industries and pioneering durian growers in Australia, Kasetsart University in Thailand, and the Southern Fruit Research Institute in Vietnam. These collaborators offer the necessary expertise and facilities to successfully undertake the project outlined. The project will combine Australian expertise in:
• phosphonate mode of action and injection technology
• biological control of Phytophthora using composted manures and mulches
• the variability and ecology of Phytophthora, and
• durian cultivation, durian diseases and disorders
with Thai expertise in:
• durian cultivation and disease biology
and Vietnamese expertise in:
• durian orchard establishment
[EBOOK] Management of Phytophthora diseases of durian
Keyword: ebook, giáo trình, Management of Phytophthora diseases of durian, Phytophthora diseases of durian, Phytophthora, durian, quản lý nấm bệnh Phytophthora trên sầu riêng, bệnh do Phytophthora gây hại sầu riêng
