Cutting rusty crops for silage or hay
From the November 2008 edition of Agriculture Today.
Stripe rust affected crops can be baled for silage or hay, the only likely disadvantage being the quality loss of the highest nutritional part of the plant - the leaf area.
Where stripe rust causes death of the green leaf area, there will be a corresponding loss in quality, so the more rust affects a crop, the greater the loss in quality.
As stripe rust requires living tissue to survive, the spores will not survive the ensiling process or being dried for hay.
There is also no known effect on livestock from eating silage or hay made from rust infected crops.
The only other issue with cutting a crop or crop-pasture mix for silage or hay will be the withholding period on the fungicides previously used in the crop.
If you are thinking of cutting a crop in a marginal area, be aware of the withholding period of any fungicides you have used or may consider using if you are growing a rust susceptible variety.
Each of the four main rust fungicides has a different withholding period, which varies for harvest and grazing or cutting.
For Propiconizole (for example, Tilt) the withholding period is seven days for grazing or cutting, for Tebuconazile (eg Folicur) it is 14 days, Terbutryn (eg Bayleton) four weeks and for Expiconazole (eg Opus), six weeks.
The withholding period can vary for different fungicide brands and for harvest it is often longer, so be sure to read the labels of any fungicides you have used before cutting a crop.
Some of the fungicides also have an additional export for slaughter interval.
In making silage or hay the potential quality will be dependant on the growth stage at cutting.
In drought stressed crops quality can deteriorate quickly, as leaves are the first to drop off as the plant puts all resources into reproductive growth.
