FUNGAL disease eyespot can cause significant yield losses and the wet 2016 season only exacerbated its presence, according to SARDI plant pathologist Marg Evans.
Eyespot mainly occurs in medium to high rainfall growing areas and can survive in stubbles for two years or longer if the stubbles have not broken down.
“Eyespot spores are rain-splashed onto plant bases and, after infection, eye-shaped lesions develop on the base of the stems, causing yield loss as well as weakness in the stem and lodging,” she said.
Dr Evans said it paid to know if eyespot was present prior to seeding “because you need to spray well before symptoms appear”.
“You could have a significant problem without even knowing, because lodging in-crop isn’t the only symptom,” she said.
While there are presently no fungicides registered to manage eyespot in Australia, there are five fungicides and a plant growth regulator in the process of being submitted for registration or label extension.
“Fungicides won’t eliminate eyespot completely, but they could give you a good return on your investment,” Dr Evans said.
Eyespot trials were conducted recently comparing Mace and Trojan wheats, with and without fungicide treatment.
“Susceptible Mace showed a 23 per cent or 1.1 tonnes a hectare yield improvement, while moderately-susceptible variety Trojan had a 7pc or 0.43t/ha yield improvement when treated,” Dr Evans said.
Eyespot is a slow growing fungus that would cause the most problems if infection occurred early in the season.
“If infection occurs early, it gives lesions more time to develop and cause problems – last year was ideal for that,” Dr Evans said.
“Early-sown crops are more susceptible to eyespot, but delaying sowing brings a large agronomic penalty and is not recommended for eyespot management.
“This makes it particularly important to know whether eyespot is present in early-sown paddocks and if it is, to consider sowing more resistant varieties and to use the best fungicide application strategy available.”
Dr Evans – GRDC grains research update guest speaker – warned growers to also be mindful of take-all, crown rot, rhizoctonia, cereal cyst nematode and septoria diseases in 2017.
Early-sown crops are more susceptible to eyespot, but delaying sowing brings a large agronomic penalty.
- MARG EVANS
Alisha Fogden
Journalist at Australian Community Media newspapers since 2007.
Journalist at Australian Community Media newspapers since 2007.
