Biofumigation frequently asked questions

1. What is the Latin name for Oil Radish?

   Raphanus Sativus  

2. Which species of free living nematode affecting Potatoes does Bento have effects on?   Bento has a direct effect on the population of Pratylenchus (currently thought to be responsible for most yield and quality losses in East Anglia). As part of its life cycle it lives in the roots of the plant. Bento is not a good host and reduces number of females and therefore significantly reduces the population (>50%) . Bento can reduce trichodorus, para-trichodorus and longidorus species through biofumigation.
 
3. Does Bento reduce Spraing (Tobacco Rattle Virus)? 
Independent trials in Germany have found that by growing Bento, Spraing incidence in the following crop was significantly reduced where as mustard actually increased the incidence. When the trichodorus nematodes feed on the roots of the Bento the virus can be stripped from the nematode. Providing the field remains weed free after incorporation (as some broad leaf weeds can be a reservoir for the virus) then the risk of Spraing (TRV) is reduced.

4. Does Bento have any control of PCN as a biofumigant?
Senova makes no claims for the control of PCN. James Lord at Leeds University tested a wide range of Brassicas under controlled conditions for activity on Pallida Juveniles and Cysts. Oil Radish was the best brassica (including hot mustards) for activity on juveniles. There was also activity on cysts although hot mustards were marginally better. To date there is no independent trials data available to confirm any effect on PCN in the field. Some growers are using a mix of the oil radish in combination with mustard for control of PCN.

5. Does Bento control Beet Cyst Nematode?  
Growing Bento has direct effect on Beet Cyst Nematode by not being a good host reducing female viability and large reductions in the population. If grower specifically requires control of Beet Cyst Nematode then Contra and Defender provide even more reductions.

6. What are the optimum conditions for Biofumigation to take place?
A soil temperature of 12 degrees and soil moisture is required in order for the macerated glucosinolates to be broken down and the isothiocyanates (ITC) gases to be produced. This gas must then be sealed into the soil.

7. What else does Biofumigation control other than nematodes? 
Biofumigation is a form of soil disinfection and so can reduce soil pathogens as well as pests. Specific ITC’s have been claimed to control specific pathogens but this is still to be confirmed by trials. Good results have been obtained with Rhizoctonia and Black dot control.

8. How does Bento compare as a biofumigant to Caliente and brown Mustards?  
Some mustards have a higher content of ITC’s produced from the breakdown of glucosinolates however Bento produces significantly more biomass.

9. What is the best way to establish Bento?  
Bento requires a fine firm seed bed. It can either be established from a ploughed seed bed using conventional seed bed preparation and drill or it can be established minimally like WOSR. Optimum row spacing is narrower than WOSR to maximise biomass and to compete against weeds.

10. How should Bento be incorporated?
In order to maximise biofumigation, the crop should be thoroughly macerated and immediately incorporated into soil using a rotovator or discs. Ploughing and pressing is also possible. It is important that gasses as sealed in by a combination of pressing and rolling.

11. How long does Bento take to grow? 
Bento requires 10-12 weeks in order to develop maximum biomass. It is not essential for the crop to have flowered although ITC production is maximized at this point.

12. Can Bento be over wintered?
Senova does not claim that Bento can be over wintered. Last season Bento did successfully overwinter in Shropshire and has proved more frost hardy than mustards. In a mild winter or where the crop is protected by snow then overwintering may be possible in some years. There are new varieties that will be completely frost hardy in future. Oil radish gives off a pungent odour as it rots so it is recommended it is incorporated prior to rotting.

13. How good is Bento as a Green Manure crop?
Bento produced between 30-50 t/Ha biomass and has been shown in Germany to take up about 25kg/N/Ha in crops that have received no nitrogen where it has been used to prevent nitrogen leaching. Where crops are grown for biofumigation the 30-50kg/N/Ha applied should be available to the next crop.
 
14. How much Nitrogen does Bento require?
Bento requires 30-50kg/N/Ha compared to 100-120kg/N/Ha and sulphur required by the mustard. This can either be applied as fertilizer or organic manure.

15. Does Bento increase the risk club root?
Providing the crop does not go to seed there should be no increase in risk of clubroot by growing Bento.
 
16. Can Bento improve soil structure?
Incorporating the large quantity of biomass oil radish produces will help prevent further losses of organic matter from the soil and over a long period of repeated growing should enable it to increase. Increasing organic matter improves the soil structure and increases the window in which it can be cultivated optimally. Oil radish has a extensive deep rooting system and therefore can restructure soil during growth too.

17. Does Bento require weed control?
Bento requires no weed control providing no weed is transplanted at establishment. Bento grows rapidly and establishes complete canopy cover out competing any weed. In order to gain benefit of any Spraing control fields should be kept weed free after incorporation.

18. Does Bento require slug control?
Bento is a Brassica and therefore could be susceptible to slug. Its relative susceptibility compared to WOSR is unknown but to date slug pellets have not been widely required. Growers should check crops frequently and apply if damage is seen.

19. Can Bento be grazed?
Oil radish is used for grazing in Canada. Biofumigation is based on biomass therefore grazing will reduce this benefit. Other benefits should be maintained providing root system is allowed to establish.

Senova Ltd, 49 North Road, Great Abington, Cambridge CB21 6AS Tel: +44 (0)1223 890777, Fax: +44 (0)1223 890666 Email: info@senova.uk.com