New supplies of nematicide Vydate (oxamyl) will not be available in time for next year’s potato planting, so growers are being advised they may need to consider alternatives.
The DuPont factory in the United States which produces nematicide Vydate for controlling potato cyst nematodes (PCN) in the soil, was damaged in an accident in November 2014 and will not re-open until January 2016. This will be too late for potato growers for next season as the product needs to be made and then sent to France for formulation before being imported to Britain.
In the UK, DuPont says it has written to customers informing them they will be unable to buy the nematicide in time for planting next year and suggesting they take this into account as they plan their rotations and crops.
Independent agronomist John Sarup of Spud Agronomy says growers who suspect their fields may be infested with PCN or free living nematodes (FLN) should have soil tested prior to making decisions about next year’s planting. Alternative nematicides Nemathorin (fosthiazate) and Mocap (ethoprophos) are available and may need to be ordered promptly, potato growers are being advised.
Nemathorin has a harvest interval of 119 days, which should not cause a problem for maincrop potatoes, says Mr Sarup. However, this long harvest interval leaves fewer options for those growing early potatoes and Mocap, with an 80-day harvest interval, may be the only conventional option for them, he says.
Biopesticide NEMGuard (garlic extract) is now on the market, and Mr Sarup suggests the product could have potential, but none of the growers who work with him have yet used it. Approval has been granted for use in carrots and parsnips and emergency authorisation was given in spring 2015 for in–furrow control of both PCN and FLN but this expired on August 11, 2015. There has as yet been no confirmation about further authorisation.
Using any of these available nematicides will increase costs of production by around £250/ha (£100/acre) if full rates are used, suggests Mr Sarup, adding growers changing from Vydate to Nemathorin or Mocap will need to invest in application equipment.
“There are some discussions around using lower rates for treating free living nematodes, but if you have PCN then you will need to use the full rate,” he says.