July 2017. What is the main mode of spread of the Fusarium species that causes Panama disease Fusarium Tr4? And secondly, what if anything should countries do which import fresh fruit from countries that are infected? And what about the countries that import root crops? Furthermore, is there a chance that footware could spread the disease?

There was thought to be little risk if the fruit were clean, and not contaminated with soil. The main method of spread of the disease is via soil movement (e.g., vehicles, agricultural implements, shoes, animals’ feet, or in water. The spores of the fungus may be present in the soil or water. Movement of infected planting material (bits and suckers) also poses a high risk of spread. There is a lot of information on the spread at: https://www.business.qld.gov.au/industries/farms-fishing-forestry/agriculture/crop-growing/banana-industry/panama-disease.

As for the question about other produce that might carry spores of the fungus, there would be need for risk assessments of each product to be imported. For imported root crops, don’t plant them next to bananas, or throw out discard pieces next to bananas.

As for bananas, it would be best to import planting material from countries without this disease. Even without soil or visible symptoms, corms may be infected. Even with heat treatment, it is very difficult to remove all cells/propagules. For footwear and tools, remove all soil then sterilize in 70% ethanol or methylated spirits. Bleach is good, but not very good for tools as it makes them rust (1 janola:10 water). Bleach should be fine for footwear. Any brand of bleach is OK. Another risk is vehicles, especially under the wheel base where dirt accumulates, and tyres. Water blast under vehicles, and tyres, and sterilize if possible using a disinfectant.

Biosecurity Queensland, Queensland Government Department of Agriculture and Fisheries has published a Grower Kit entitled: Panama disease tropical race 4. It covers Identification, On-farm biosecurity, Biosecurity Queensland processes, Standards and guidelines, FAQs and Contacts. DAF provided 10 copies for Pacific island countries.

You can find the Grower Kit here divided into 20 PDFs: https://publications.qld.gov.au/dataset/panama-disease-tropical-race-4-grower-kit

A point was raised on the safety of bleach. The active ingredient is sodium hypochlorite. Just beware of industrial strength products, because they are often strong concentrations (cheap but also dangerous). Best to decide on a dilution based on knowing the % sodium hypochlorite in the original product/container. So, at high rates it should be treated just like a poisonous pesticide (wear protective gear when decanting and diluting it, especially wear protective glasses and gloves). At industrial rates it will burn holes in your clothes, and your skin and a splash could easily blind you. We use it to sterilise our insect rearing equipment, and it is very useful because UV (sunlight) degrades the a.i. very quickly, leaving no residues. Low concentrations are okay. We even sterilise the surface of fresh leaves with a very low concentration.