Italian Rye-grass is very similar to Black-grass in its germination pattern, seed persistence and the depth from which seedlings can emerge.
Although herbicide resistance is currently less of an issue with Italian Rye-grass, its wide UK occurrence and the weed’s aggressive nature should make it a major concern in control programmes.
Effective cultural alongside chemical controls are, therefore, crucial for the most sustainable Italian Rye-grass management.
The best Black-grass herbicide programmes will also give effective Italian Rye-grass control, making specifically-targeted treatment only necessary where black-grass is not also a problem.
WARNING: As well as having a greater potential for rapid spread than Black-grass, Italian Rye-grass is a more competitive weed, making effective early control of infestations even more important.
Plough well to bury seed but not more often than every 4-5 years
Rotational ploughing can give excellent immediate Italian Rye-grass as well as Black-grass control, especially where years of shallow tillage have kept the weed seed bank near the soil surface.
Ploughing will not be as effective where Italian Rye-grass seed is spread throughout the soil profile and ploughing again within 4-5 years can bring viable seeds back to the surface to germinate.
Several years of shallow tillage is recommended after ploughing to keep any remaining weed seed near the surface where it can be controlled with glyphosate stale seedbeds.
WARNING: For the greatest control ploughing needs to give complete soil inversion and bury all trash. Otherwise, too much Italian Rye-grass seed will escape burial to a depth from which it cannot emerge.
Integrate cultural controls with the best herbicide programmes
Although Italian Rye-grass is still reasonably well-controlled with herbicides in most cases, cultural controls should always be integrated with the most appropriate spraying programmes to combat resistance development.
Pre-planting glyphosate is vital to remove all weed growth before drilling, and where planting is delayed by more than a few days a permitted glyphosate is also recommended post-planting but pre-emergence of the crop.
Residual pre-emergence cereal herbicides are essential and post-emergence treatments should be targeted at the youngest possible weeds, with herbicide actives rotated over successive seasons to minimise the risk of resistance development.
Where cereal crops still have high levels of Italian Rye-grass in the spring spraying-off patches – or even whole fields – with glyphosate will be important to limit seed return.
WARNING: If herbicide resistance is suspected, seed or plant samples should be resistance tested to establish their exact status and ensure only the most effective in-crop chemistry continues to be used.
Delay autumn drilling or introduce spring crops