The GRDC northern region crop disease survey collects information about the distribution and spread of established and emerging crop diseases. It also conducts proof of area freedom surveillance for five high-priority exotic diseases.

Led by Queensland Department of Agriculture and Fisheries pathologist Lisa Kelly, the project is a partnership between industry and state and federal agencies to provide disease surveillance and related diagnostic support in major production areas of the northern region, including Queensland and northern New South Wales.

“Unfortunately, COVID-19 travel restrictions meant travel was restricted to Queensland during 2020, however 123 crops were surveyed and more than 365 disease samples were processed,” Ms Kelly says.

“The diverse cropping system in the northern region provides growers with important rotational opportunities to control diseases and weeds at the same time as responding to commodity prices.

“However, some crop rotations can also carry diseases between cycles, making the survey important as it captures changes in the occurrence, distribution and severity of diseases, which can be used to inform research, as well as by growers and agronomists when making management decisions.”

Diseases identified

The 2019-20 survey included wheat, barley, mungbeans, sorghum, soybeans and peanuts and identified the presence and distribution of several important established diseases.

“Spot form of net blotch and Powdery mildew were prevalent diseases in barley paddocks inspected across southern Queensland,” Ms Kelly says.

“In mungbean crops, significant outbreaks of Tobacco streak virus occurred in central Queensland, while in southern Queensland Fusarium wilt and Powdery mildew were widespread during the 2019-20 summer.

“Anthracnose and Target spot affected soybean crops in the Burdekin region in early 2020. In contrast, a low incidence of disease was found in wheat, peanut and sorghum crops.”

Exotic diseases also pose a risk to grain industries and Queensland’s long northern coastal border creates a high-risk disease pathway into the country from Papua New Guinea and South-East Asia.

“The close proximity of these countries increases the possibility that new diseases will reach mainland Australia and become established, making early detection crucial to containment and possible eradication.”

Surveillance objectives refined

To mitigate this risk, Ms Kelly says the survey has expanded to include more refined surveillance objectives for exotic diseases.

“While we have conducted surveillance for established diseases over the past five years or more, the 2019-20 survey was the first to actively report absences of specific exotic pathogens.

“Surveillance for high-priority exotic grain pathogens provides the best chance of early detection for containment and eradication and also provides data for proof of area freedom.”

The five exotic diseases included in the 2019-20 survey were:

• Mungbean yellow mosaic virus (Begomovirus)
• Sorghum downy mildew (Peronosclerospora sorghi)
• Barley stripe rust (Puccinia striiformis f. sp. hordei)
• Wheat blast (Magnaporthe oryzae – Triticum pathotype)
• exotic pathogenic Stem rust races (Puccinia graminis f. sp. tritici, for example Ug99).

All five are high-priority exotic diseases of the Australian grains industry.

“Reassuringly, no exotic pathogens were detected during the 2019-20 surveillance and diagnostics activities across Queensland.”

However, Queensland grain growers are encouraged to always look out for any unusual pests or pathogens; and to contact the Department of Agriculture and Fisheries to send in any samples they are unsure about.

If you find an unusual plant pest or disease the national Exotic Plant Pest hotline (1800 084 881) is the number to call.

More information: Lisa Kelly, lisa.kelly@daf.qld.gov.au, visit Plant Health Australia for exotic grain pests and diseases.