There are two diseases that are abrreviated to "Rhizo", but there are very different diseases. The disease rhizoctonia (Rhizoctonia solani) has been found in several beet crops in the last two seasons. This is a soil-borne fungus that leads to a black rotting of infected bulbs, and observations suggest large yield reductions (e.g. 5-8 t DM/ha) are occurring in badly affected paddocks. It has been more common in some regions (e.g. lower North Island, west coast of the South Island), as the disease prefers moist and warm weather during early crop stages.
We are not aware of any treatment that is effective. Paddocks that show some signs should be spelled from further beet crops for as many years as possible. The fungus is present in soils that have never grown beet because the disease is also hosted by other crop species (e.g. potatoes, wheat) and some broadleaf weeds.
This depends on the cultivar. The cultivar Tower has been selected for palatability and late heading date, and has the same quality as perennial ryegrass during winter and spring. In summer however, a Tower/clover pasture has higher feed quality than a ryegrass/clover pasture.
Tall fescue can fail to persist if it is not established well in clean seedbeds with good soil fertility. Also, most cultivars have a low tiller density and are clump-forming grasses, so they are often overrun by sub-tropical grasses (e.g. kikuyu, carpet grass). Tower is has a dense and spreading habit, quickly forming a sod that is resistant to weed grass invasion.
Farmers often grow special pastures of herbs or clover to finish lambs, but others also use a grass for this purpose.
Perun festulolium has been known for some time for its production and robustness, even in difficult environments (droughts, severe winters), but has now also earned a reputation amongst users for outstanding animal performance. This was again verified in an animal trial conducted in 2014 where cattle grew faster on Perun than Italian ryegrass.
Farmers can use Perun, either on its own or with clover, as a high performance crop to grow lambs and cattle at improved rates. A key advantage over other crops is that a wider range of herbicides can be used to effectively and cheaply control weeds.
It is recommended to have 4-5 years between fodder beet crops. Double-cropping, or a shorter rotation, will speed up the spread of root diseases in the soil. Eventually these diseases will cover enough of the paddock to cause very large yield losses (e.g. 50%), which are sudden and cannot be predicted. A break of 4-5 years does not guarantee there will be no problems, but it does reduce risk considerably. Be aware that the 4-5 year break also applies to paddocks that have been used to hold animals while they are on beet crops.
No. Cattle grow at the same rate on low dry matter or medium dry matter varieties of fodder beet. This was confirmed in a trial conducted at Winchmore in 2016, click here for a full report.