Australian researchers discover four new chilli pathogens

By RJ Whitehead

- Last updated on GMT

© iStock
© iStock

Related tags Fruit Australia.

Scientists in Melbourne have identified four new pathogens previously not found in Australian chillies, raising the stakes for the country’s quarantine and disease resistance efforts.

The pathogens, all part of the Colletotrichum​ species, cause anthracnose, a fungal disease which lowers yield and produces large, sunken black spots on a variety of fruits and vegetables.

While anthracnose already exists in Australia, the discovery of the four new pathogens raises important new questions about how to better protect Australia’s horticultural industry.

The pathogens have a broad host range, meaning they are able to infect other fruits and vegetables, particularly tropical fruits such as papayas and mangoes.

Paul Taylor of Melbourne University said the discovery highlights the need for an effective and efficient diagnostic quarantine system in Australia.

Before this study, there were only two species of ​Colletotrichum thought to exist In chilli here​,” he said.

The identification of four new ones suggests we need to keep a closer eye on the status of existing pathogens, otherwise our billion-dollar agriculture export industry is at risk​.”

His team analysed infected chilli fruits from Southeast Asia and Queensland, the hub of production in Australia which produces around 40,000 tonnes of chilli and capsicum over 1,722 hectares a year. Their findings were published in the journal Plant Pathology​.

Using molecular techniques and classical taxonomy, the researchers identified three Colletotrichum​ species not found before in Australian chillies—C.siamense​, C. simmondsii​ and C. queenslandicum​—as well as C. cairnsense​, which had never before been identified.

Currently, Australian growers manage anthracnose with fungicides, but the identification of the new pathogens will contribute to efforts to build disease resistance in chilli plants.

This disease is particularly hard to control because of the number of pathogens that make it up​,” Prof. Taylor said.

On the positive side, our analysis did not detect ​C. scovillei, which has caused major problems in Southeast Asia and has spread heavily throughout Indonesia, Malaysia, Thailand and Taiwan​.

With further research we can hopefully prevent the incursion of new exotic ​Colletotrichum species into Australia​.”

Prof. Taylor has called for more expansive surveying of chillies to allow for the identification of pathogens, as well as the development of tests that will make diagnoses even easier.

Identification and monitoring of pathogens is the only way to mitigate chilli disease in Australia​,” he said.

There is a real lack of tools available right now to industry and quarantine personal that we need to address​.”

Source: Plant Pathology
“Colletotrichum species associated with chili anthracnose in Australia​"
P Taylor et al

Related topics Policy Oceania Supply chain

1 comment

Retired Scientist

Posted by Dr V K Tiwari,

In India such research is not identified for commercial horticultural crops,but your team needs to see it is eradicated every where.

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