Winter Wheat
All T3 fungicide applications onto winter wheat should now be planned for application over the next couple of weeks. Winter wheat crops have moved at exceptional pace during the dry warm period over the last couple of weeks. The cornerstone for the T3 head spray fungicide is a strong triazole that as well as being effective on Septoria is also effective on Fusarium. Prothioconazole & epoxiconazole remain the most effective products to give ongoing Septoria protection. Tebuconazole and metconazole are very strong triazoles for Fusarium and an important contributor at this time. The addition of a strobilurin is also essential to maximise the persistence of the triazole and strengthen activity on Yellow Rust. Good grain fill is totally dependent on retaining green leaf area for as long as possible, and the addition of the strobilurin extends the retention of green leaf tissue. Pyraclostrobin (COMET) is still the highest rated strob for use in wheat being the strongest performer on Yellow rust and the late ear disease. I have seen a lot of physiological tipping on winter wheat and there are a lot of theories as to what may have caused this but most noticeably it seems to be specific to certain varieties. Mildew has been present on most cereal crops this season where the variety has low resistance a mildewicide must be included in the fungicide program.
Spring Barley
It is fair to say that most spring crops have made a remarkable recovery over the last couple of weeks. All weed control should now have been carried out on spring barley crops and the T1 fungicide application must be planned as rhyncho is now showing on varieties Concerto and Waggon. The two most dominant diseases in our climate are powdery mildew and rhynchosporium with ramularia becoming an increasing problem over recent years. Ramularia can be difficult to identify but unlike most other physiological leaf spots which are only visible on the upper side of the leaf ramularia is easily seen both on the upper and lower surface of the leaf and the longitudinal edges of the brown lesions remain enclosed by the leaf ridges. Symptoms appear where crops are subjected to stress from alternating periods of wet weather & sunshine, or man-made as a result of scorching.Chlorothalonil (BRAVO) is very effective when used preventatively, helping to maintain green leaf area when used along with a triazole/strob mixture.
All weed and disease control should now be complete on both spring wheat and oats.
Grassland
Attention must now be given to those grass fields which were not sprayed prior to first cut. Grassland herbicides use growth function to kill weeds, therefore peak growth periods should be used for herbicide application. There must be sufficient growth to allow herbicides to be effective and vegetive growth is the key time to apply, as the chemical then gets drawn down into the roots. Herbicides are less successful once plants have progressed to the reproductive stage and have thrown a stem or began to seed. Once weeds are beyond the ideal growth stage for spraying they should be mown or topped and allowed to regrow again, and a herbicide applied to the fresh young growth.
To optimise efficacy of any herbicide, recommended water volumes should be observed, even when it means more time spent spraying. It is important to note ragwort plants in their second year are now coming close to flower and should be sprayed immediately as flowering ragwort is poorly controlled. The routine herbicide treatments for this weed are full rate MCPA or 2, 4-D, and they are most active on growing rosettes with reduced activity as the stem starts to extend. They are not clover safe. You can use a mixture of both these products as Nufarm Lupo which allows an increased dose herbicide compared with either alone, with a consequent activity benefit. Forefront is the most effective herbicide on ragwort.
Stock must be kept off until the weeds have rotted away, which can take up to six weeks.