Certis’ garlic-based nematicide NEMguard DE has been authorised for use in sugar beet to reduce Docking disorder symptoms caused by free-living nematodes (FLN).

Docking disorder symptoms – stunted plants, root fanging and reduction in root size – are caused by FLN Trichodorus spp. & Paratrichodorus spp. (stubby root nematodes) and/or Longidorus spp. (needle nematodes).

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These nematodes are prevalent in light sandy soils which comprise 10 to 15 percent of the beet growing area.

Previously yield losses were minimised using nematicides such as Vydate (oxamyl) which is no longer available.

BBRO has sought alternatives and in conjunction with NEMguard DE manufacturer Ecospray and distributor Certis conducted three in-field strip trials in 2021 to test it against Vydate and untreated controls on FLN vulnerable sites.

BBRO crop protection scientist Dr Alistair Wright says it was a year with perfect conditions for FLN and following the trials BBRO are confident that NEMguard DE worked as well as Vydate for FLN management. 

The treatments were compared by assessing the extent of fanging damage to roots from 0 with no fangs to 4 with severe fanging and damage.

The graph below right shows results from one field site near Thetford, Norfolk where a 10kg/ha dose of NEMguard DE halved the fanging score.

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“This should result in significantly greater recovered yields when mechanically harvested.”

NEMguard DE is a granule formulation containing 450g/kg garlic extract which is applied at drilling via a granule applicator. 

BBRO initially recommends a 10kg/ha dose of NEMguard DE/ha which it believes will provide adequate protection of 2022 crops. This rate may be refined over time. 

Dr Wright reminds growers that granule applicators will need to be serviced and calibrated ready to dispense this dose at drilling and advises that:

“Soils can be sampled for FLN, with Trichodorus populations more than 1000/litre of soil or with Longidorus populations more than 100/litre of soil indicating risk of damage.

“On land with a history of FLN damage, the use of a nematicide is usually worthwhile. 

“No tolerant varieties against FLN damage currently exist so use of a nematicide is strongly recommended.

“NEMguard DE will not control beet cyst nematode (BCN) so if concerned about it, use a BCN tolerant variety e.g., Daphna, Katjana or Lacewing.”