I started growing pasture seed at Holbrook in 1972. My seed crop then was certified Seedmaster Phalaris.
The main weed problem in that crop was annual ryegrass (and still is). Advice from the Department of Agriculture and other seed producers was that Gramoxone herbicide for its control was common. Gramoxone was used in conjunction with Reglone, satisfactorily. Crop damage and weed control was variable.
Following the use of Gramoxone there was a large swing by seedgrowers to the Bayer powder product, Karmex (Diuron). Karmex was used on phalaris for many years at rates up to 3 lbs/ac and gave excellent control of annual ryegrass, capeweed, barley grass and clover, but it did not control brome grasses.
Because this product was reasonably safe and effective, I, and many other growers, kept using it, as human nature dictates “when on a good thing stick to it”. This has since turned out to be a mistake and has encouraged the resistant types of annual ryegrass to flourish.
The resistance problem has also occurred in the production of Currie Cocksfoot with annual ryegrass as our main weed. Control was effective using Hoegrass at 1.25 LIha. However, after 3 years of Hoegrass I find its control has diminished and other farming practices must be undertaken.
The Hoechst Company has tested the annual ryegrass seeds for herbicide resistance with positive results. Hoegrass appears to give variable effects unless growing conditions are suitable.
In growing oats for grain the control of annual ryegrass using Glean at the recommended rate is very effective providing the correct timing of application is used. I would suggest that Glean be used no more than two years in succession.
Living with annual ryegrass
Since the problem of herbicide resistance has become evident, we have decided to rotate our crops more often. Whereas some certified grass seed crops had previously been in production for over 6 years, we now rotate the areas with cereal grain, clover seed production, grazing and lupin crops. This allows us to avoid the use of the same or similar chemical groups. If we put a paddock Out to grazing we then allow the more vigorous annual ryegrass to dominate the less vigorous ryegrass which appears to be the herbicide resistant form.
Two years ago I travelled overseas to Denmark, Oregan (USA) and the United Kingdom to review seed production processing and cleaning plants. After returning I established HOLBROOK SEEDS, which is a new seed growing, processing and marketing business, catering for consumers, both retail and wholesale, locally and overseas.
With the need for farmers to increase carrying capacity to become more profitable and efficient, and the growing concerns by Landcare groups to establish perennial grasses in recharge areas to help prevent salinity under dryland conditions, the pressure is on people like myself to deliver clean, high germination pasture seed to the market. To do this we must be able to control problem weeds like annual ryegrass and to learn to avoid creating problems such as herbicide resistance.
At Holbrook Seeds we grow certified Currie and Porto cocksfoot, Demeter fescue, Sirosa phalaris, Karridale and Junee subclover, oats and lupins. We also contract-clean seed and grain for other growers. We have thus used many different herbicides at different rates to control annual ryegrass.
I think much more research is needed to help farmers in their search for measures to control herbicide resistant weeds. Advice on timing, period of usage and crop rotation would be of great importance to farmers.
While staying with farming friends during my tour of UK farms, I was most impressed by the syndicated usage of what are called AGRICULTURALISTS. These specialists are employed by groups of farmers who monitor the growth of crops and report weekly to the farmers. Advice is given regarding herbicides, insecticides, fungicides, fertilisers, growth regulators, etc. I suggest that there is room in Australia for such specialists.
Finally, if farmers are not made aware of herbicide resistant weed varieties, the growing of high yielding crops will become impossible. Striving to grow better and cleaner crops is reflected in profit and with better profits the future is well assured.
Ryegrass controlled (%)
Hoegrass (1 L/ha)
Hoegrass (2 Lfha)
Glean (25 g/ha)
Sertin (0.5 L/ha)