Wheat growers on alert for key wheat disease after the dry
A return to wetter conditions could present a sizable disease problem for wheat growers, particularly on higher yielding varieties under short rotations.
AW Vater & Co Agronomist Zack Zweck said septoria was particularly worrying on the Yorke Peninsula, with potential for yield losses between 20 and 30 percent.
“We started to see a lot more septoria in 2016, when we had the wet spring,” he said.
“There’s a few agronomists who are thinking like me; Septoria is a storm that’s building and when we do get a good spring, it could really punish us.”
Zack was involved in a trial, comparing popular foliar fungicides alongside ELATUS™ ACE, prior to registration last year. Loaded with a Group 7 active constituent, benzovindiflupyr, and a DMI (group 3), ELATUS ACE will help with resistance management.
“ELATUS ACE was certainly the best performer in the trial,” Zack said.
Few wheat varieties offer much in the way of genetic protection against Septoria tritici blotch. This is especially the case in higher yielding varieties, with resistance cases now noted across South Australia, Victoria and New South Wales. The pathogen survives season-to-season on wheat stubble, with back-to-back wheat particularly susceptible.
Some of the more popular, high-yield wheat varieties have unfortunately experienced significantly more incidence of septoria than others.
“Land is quite pricey around here and you can’t blame growers for wanting to make a good return, using those varieties,” Zack said.
Where possible, Zack encourages his growers to take a strategic approach to septoria.
“I do encourage them to grow different varieties and I urge them to get a preventative spray on early, before the disease sets in,” he said.
“Typically, we have gone in with triazoles at growth stage 30 to 32, and a quality fungicide at the flag leaf stage, particularly AMISTAR® XTRA. ELATUS ACE is definitely a quality product.”
Prevention is better than the cure but Zack sees there being a greater degree of flexibility with ELATUS ACE as compared to other products.
“From the trial work, we saw excellent results as early as GS 23,” he said.
“By keeping the disease out, we aren’t seeing that secondary infection climb the plant, it displayed quite a bit of residual activity."
“Equally, if septoria did get away in a crop that didn’t get an early spray, ELATUS ACE could be used at the flag leaf stage to protect those higher leaves.”
In the past two seasons Zack said yield penalties of 5 to 10 percent have been common.
“It’s been a disease that growers have been pretty lucky with,” Zack said.
“Those products growers have used to control rusts have been masking the issue, but these sprays haven’t achieved the control of septoria that’s been required.
“If growers are getting screenings at harvest, the crop has clearly suffered at grain-fill. Ruling out other causes like moisture or heat stress, there’s a good chance septoria is at fault, and that can see samples fall from grade one to grade two, with a significant price penalty.”