Growing beet with KWS
This technical newsletter, designed for the beet grower is aimed to help improve beet growing knowledge with seasonal and timely advice on all aspects of growing beet.
Bolters and weed beet, foliar disease and pests
The fodder beet growing season started in difficult conditions, the cold and wet spring delayed drilling and the wet start to summer has seen large variability in crops. Poor looking crops might be associated with earlier water logging, soil compaction and/or nutrient leaching from heavy rainfalls in May/June. As the season moves on, we are looking at such topics as bolting, 2nd generation of leaf miner as well as first plants being infected with powdery mildew and potentially rust.
Weed beet and bolters
Fodder beet, when exposed to cool temperatures over a period of time, (0 – 120C for 30 – 40 days) will produce flowering plants (bolter). Those will subsequently produce viable seed which if not controlled will cause a weed beet problem in the future. On average one weed beet per m² can reduce yield by 11%. As such, it is crucial that any bolters present and any existing weed beet are routinely controlled and destroyed each year before they are able to produce viable seed.
Removal of weed beet
Bolters can be controlled by three methods: pulling, weed wiping or cutting, depending on the number of bolters present.
Pulling: < 1,000 bolters / ha
If the plants have not started to set seed, pull them up, break the stems close to roots and drop in the field (ideally on top of the crop canopy to prevent re-rooting). This is a faster operation than having to carry weed beet plants off the field. However if the seed begins to mature it is advisable to remove the bolters from the field to avoid any seed from shedding onto the field.
Weed wiping: 1,000 – 10,000 bolters/ha
At this number of bolters it is worth considering weed wiping, however some key points need to be taken into consideration:
- young weed beet are most susceptible to wiping
- ensure a good coverage of chemical by wiping the crop in both directions
- where bolters have roots of harvestable size, there is a risk of rotten roots spoiling the sample especially if beets are harvested early
- beware of dripping chemical and treated seed flicking onto healthy plants causing damage
For more detailed advice and the right product, please ask you BASIS trained agronomist.
Cutting: >10,000 bolters/ha
The best machines are those that tend to macerate the bolters into small pieces to prevent regrowth. Control can be very effective if 2-3 cuts are used, starting approx. 14 days after flowering begins and repeating at 14 day intervals. Cutting height - the first cut should be ~20cm above the crop. This encourages any subsequent branching to take place above the plant canopy. The final or only cut should be just above crop canopy - any subsequent branching will be under the canopy. Use Front mounted cutters as rear mounted ones can miss plants pushed over by the tractor.
Powdery mildew (Erysiphe betae) has been found on sugar beet crops across several counties in the east. Therefore it might be advisable to inspect your fodder beet as well, if not done already.
The first symptoms of powdery mildew are small, scattered, and whitish areas on older leaves. The fungus then spreads rapidly, mostly on the upper leaves, and the plants appear dusty white. Powdery mildew can cause the greatest yield losses as it arrives early in the season. Losses of up to 30% are possible but can be prevented by fungicide application. Fungicides containing a strobilurin and triazole will not only protect the leaf but provide a greening effect and likely yield boost.
Depending on your harvest date you might consider two fungicide applications to maintain a strong and healthy canopy. A second spray might also be worth considering if rust appears in late summer/autumn. Rust (Uromyces betae) is identified by small, raised and circular orange-brown pustules often surrounded by a lighter halo.
If you detect any signs, please ask your agronomist for a suitable treatment.
Not seen as frequently as last year, you might still detect some leaf minor damage on your plants. Leaf miner, the larvae of Mangold fly (Pegomya hyoscyami), causes damage by feeding between the upper and lower epidermis, leaving those parts transparent. Early attacks might cause economic losses and sensitise the plants to herbicide damage. If you encountered problems this year, you might think of choosing insecticide treated seed for next year, as this will protect the plants from the first generation of leaf miner.
- August CultiVent 2016 feedbeet [pdf | 0.96 MB] pdf Download