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Photo 1 Net blotch in early tillering barley.jpg

‘Old foes’ reappear with improved conditions

A few ‘old foes’ in the form of powdery mildew, net blotches in barley and stripe rust in wheat reappeared in 2020 alongside improved seasonal conditions.
Photo 1 Net blotch in early tillering barley.jpg

Although relatively easy to control, the past ten years have seen some strains show increased levels of resistance to our key cereal fungicides.

Most growers are aware of problem weeds like ryegrass developing resistance or tolerance to key herbicides over time. Likewise, it is important that growers prioritise crop disease and fungicide resistance when planning crop programs and rotations. Powdery mildew particularly has been shown to rapidly develop resistance to triazole fungicides.

To help reduce disease levels and slow down the development of fungicide resistance, there are six main areas of focus:

  1. Avoid susceptible varieties
  2. Rotate crops - use time and distance to reduce disease carry-over
  3. Use non-chemical control methods to reduce disease pressure
  4. Spray only if necessary and apply strategically
  5. Use the correct rate for the situation - unlike herbicides avoid overdosing
  6. Rotate and mix fungicides (mode of actions groups)

ADAMA Australia developed and released Topnotch™ Fungicide in 2019 to assist and encourage growers to use multiple (mixed) modes of actions together to help slow the speed of resistance development occurring.

Topnotch is a mixture of Group 3 and 11 modes of action, which gives the fungicide a high level of control on a wide spectrum of diseases in barley, while reducing the selection pressure on a single mode of action which will assist in prolonging the effective life of fungicides currently available. Oats will also be added to the label for 2021.

Commercial Manager for ADAMA Australia in Northern NSW, Peta Miguel says: “Farming operations in the northern cropping belt are becoming increasingly complicated. Growers need to manage the time pressure of winter and summer cropping operations overlapping, and Topnotch offers a simple one drum option that covers all the key cereal crops and diseases while helping to slow the development of resistance.”

The Pursehouse Rural agronomy team utilised Topnotch in several commercial situations in 2020 with pleasing results, according to Pursehouse Rural agronomist at Gunnedah, Matt Roseby.

“We used Topnotch last season based on its cost-effective broad-spectrum disease control in barley where we see it having a good fit. In a high-pressure year, it gave excellent control in barley crops and what stood out for me was its residual length - how clean it kept the crops after application. I was very happy with the results and plan on recommending it again this coming season if required,” he says.

The Research and Development team at ADAMA Australia has continued to focus on challenges in disease management in key broadacre crops for the past ten years.

In addition to the release of Topnotch in 2019, the company will be adding two additional products to its fungicide portfolio in 2021, with Maxentis® EC and Proviso® EC. These products will offer effective control of various cereal diseases (including registrations in oats), along with canola diseases such as sclerotinia and blackleg. Proviso EC will also give growers another option for fusarium head blight in durum wheat varieties.

For further information on Topnotch fungicide, growers and advisers can contact their local ADAMA Australia representative or visit