Low-rate nematicide will help impove pest control in potatoes

A liquid nematicide with a very low application rate is being launched for next spring which will give levels of potato cyst nematode (PCN) control approaching that of full-rate granular products at half the cost.

Agrochemical and seed giant Bayer says its Velum Prime, based on the SDHI fluopyram, will be widely available for use in spring 2019 after seven years of trials investigating its performance against two PCN species Globodera rostochiensis and G pallida.

Neil Thompson, Bayer channel marketing manager for root crops, says the product is by no means the complete answer to the problem posed by nematodes, but it will be part of the solution and at a lower cost.

“There are a range of prices of granular nematicides, but Velum Prime is likely to be around half the cost of granules,” said Mr Thompson.

The new product when applied at 250g of active substance at the full label rate of 0.625 litres/ha, is an attractive proposition for growers who previously had to use specialist equipment to apply 30-55kg/ha of a granular product, he added.

See also: How to sample soil for potato cyst nematodes

Initial approval

The initial approval is for an in-furrow application at planting, similar to that with azoxystrobin, but Bayer hopes to receive an approval for a spray applied using a conventional sprayer and incorporated before planting.

In addition, the new product does not have a harvest interval restriction, which will potentially extend nematode control to those unable to use granular nematicides, such as growers of salad crops.

Mr Thomson points out that although the product is not a “silver bullet” for PCN control, it will play a significant role in PCN management and reduce reliance on organophosphate and carbamate chemistry.

It has a new mode of action to other nematicides, and across more than 30 trials delivered an average yield increase of 3.3t/ha and a reduction in nematode eggs, he added.

It can be used on its own in low/moderate PCN pressure situations but in higher PCN pressure, it can be used in sequence with reduced rates of granular nematicides, Mr Thompson said.

“The use of Velum + half-rate Vydate (oxamyl) gave an increase of 2.6t/ha over the full rate (55kg/ha) Vydate-only treatment, while a similar treatment of Velum with half-rate Nemathorin 10G (fosthiazate) gave an average yield increase of 0.3t/ha over the full rate (30kg/ha) Nemathorin-only treatment,” said Mr Thompson

Although not a label recommendation, additional trials investigating its performance against tobacco rattle virus (spraing) – a virus transmitted by free-living nematodes – found the new product reduced the incidence of spraing from 17.45% to 7.65% in four trials.