Summary

Resource availability is changing how and where rice is grown in Australia, and this is presenting new challenges for pest and disease management. In NSW minimising water use has led to increased repeat cropping which has intensified snail damage, and there is evidence that delayed permanent water and mid-season dry-down have increased the incidence of damaging armyworm infestations. Bloodworms continue to be an issue for growers sowing both by air and using ground broadcasting. Anecdotal evidence suggests increased levels of seedling diseases affecting establishment in dry broadcast crops, whilst the spectrum and distribution of diseases across the NSW crop remains unclear due to a lack of systematic surveys, making it difficult to formulate policies on external biosecurity risks. The expansion of rice production into new regions and the resumption of rice production in former rice areas in northern Australia poses a risk to biosecurity, as diseases (such as rice blast) present in these areas may be amplified there and be more readily transferred to other regions. In this project we will conduct strategic field and laboratory research aimed at resolving these growing biosecurity issues.

Program

Rice

Research Organisation

The Crown in right of the State of NSW acting through the Department of Primary Industries

Objective Summary

1. Conduct a systematic field survey of rice diseases present in the southern NSW rice crop, using established survey and diagnostic techniques. This will form a basis for the assessment of the risks posed by external disease threats, and allow future research on rice diseases to be prioritised.

2. Screen candidate pesticides in the laboratory for their potential to control rice snails. This work will focus on newer generation chemicals released since the last screening program approximately 12 years ago, and will look at products that already have a registered crop use in Australia, as experience has shown that effective chemicals with no other registered use pattern will not reach the market here due to high registration costs.

3. Complete a series of glasshouse studies using different soil types and rice varieties to determine whether the incidence of seedling diseases and associated seedling mortality is affected by dry broadcast sowing, which exposes the seed to fungal pathogens during the full imbibition period. Results will be used to adjust recommended sowing rates where necessary.

4. Determine whether water conservation practices (especially mid-season dry-down) increases the incidence of armyworms, and whether this is associated with a fall in parasitism rates.

5. Conduct a replicated trial to determine whether netting can be effectively used to exclude ducks from bloodworm control trials without affecting bloodworm colonisation patterns. This is an essential precursor to future evaluations of new bloodworm control treatments.