Project reference: 2002-04
Damping-off of seedlings caused by Fusarium circinatum
Project description:
The pine pitch canker fungus, F. circinatum, has been recorded causing devastating losses in pine nurseries overseas. It can infect seedlings at, or just above, the soil-line and it may act as a typical root-infecting pathogen. Both pre- and post-emergence damping-off have also been attributed to the disease. In New Zealand many soil-inhabiting fungi have been associated with damping-off. Damping-off can be described as generalised collapse of the tissues of very young seedlings, and causal agents cannot be separated on the basis of symptoms alone. Many of the fungi capable of causing such collapse have a very wide host range encompassing both conifers and angiosperms. Although the pathogenicity of F. circinatum to Pinus spp is recognised, the capability of this fungus to cause damping-off to other conifers or to other seedlings has not been reported.
The potential for seed of conifers that are not susceptible to pitch canker (eg. Douglas fir) to carry the fungus and to provide a source of soil infection has been discussed and reported. An understanding of the possible effect of F. circinatum on young plants other than pines would assist in our state of preparedness in the event of an incursion.
The objective of this proposal is to determine the capability of Fusarium circinatum to cause damping-off of seedlings of species other than pines in laboratory conditions. The experimental work is separated into two parts, the first encompassing pre-emergence damping-off and the second post-emergence damping-off. It is proposed that the two parts would be carried out in consecutive years.
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Pre-emergence damping-off: Seed of Pinus radiata, P. pinaster, Eucalyptus fastigata, E. nitens, Pseudotsuga menziesii, Cupressus macrocarpa, Lolium perenne and Trifolium repens will be sown in trays (three replicates per plant species) containing heat-sterilised standard potting mix that has been infested with F.circinatum. The trial will also be fully replicated with one of the established damping-off fungi, and with a common saprophyte, to act as controls. Emergence and survival will be monitored.
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Post-emergence damping-off: Two-month-old seedlings of the plant species listed above will be inoculated at the root collar with the 3 fungi. The trial will be fully replicated as outlined above.
All work will be carried out within the Biohazard Safety Cabinet in the quarantine facility at Forest Research, Rotorua.
Funding: As our FORST programme is under review for 2003-2004 I cannot confirm that FORST funding will be there for the second year, though I anticipate that it will be. Stage 2 of this proposal, the post-emergence damping-off will depend on the results from the pre-emergence damping-off trial. If results are negative for some species then the work would be scaled down.
Research Provider:
Forest Research
