Early reports of stem, leaf and stripe rust in wheat crops have confirmed the carryover of rust on the significant green bridge from 2010. This reinforces the need for growers to take an active approach to rust management. Early rust infections in crops increase their potential to cause yield loss if control strategies are not implemented.

There have been reports of early stem rust and leaf rust infections in wheat crops in the Mallee. Likewise, there have been reports of stripe rust in the Horsham and Bendigo districts.

Farmers and agronomists, in all cropping regions of Victoria, are advised to monitor their wheat crops for stripe, leaf and stem rust. If rust is detected, check the rust resistance rating and implement your rust management plan. Rust resistance ratings are available in the DPI Information Note: Cereal Disease Guide 2011. Farmers and agronomists are advised to consider spraying earlier than usual this year.

What to look for

At this time of the year it will be necessary to look closely at plants to detect the small pin head size rust pustules, especially on the lower leaves.

Monitoring

Farmers and agronomists are advised to actively monitor for symptoms of rust and inspect crops regularly. Focus on the more susceptible varieties. Rust can affect all parts of the plant. Carefully inspect the leaves, especially the lower, older leaves, as well as the lower stems.

Fungicides

Fungicides will give better control of rust when applied early in the epidemic. The degree and duration of suppression depends on the application rate and coverage.

There are a number of products registered for the control of rust in Victoria. However, it is always important to read the chemical label before use. Note that tebuconazole (eg. Folicur® and other registered products) degrades slowly in plants. Therefore, restrictions apply  regarding the total amount that can be applied per season to one crop. Only one application of any product containing 430 g/L tebuconazole at the maximum label rate of 290 mL/ha can be used in a crop. This will ensure harvested grain does not exceed the maximum residue  limit (MRL) for tebuconazole.