According to research conducted by Produce Solutions, a group of potato agronomists, a sequential approach using a liquid nematocide with a new mechanism of action, along with an existing granular product, is the best strategy for controlling the potato cyst nematode.
The company spent three years testing Velum Prime (fluopyram) in Shropshire, using it alone and sequentially with granular nematocides at varying rates. The firm now has a clearer picture of its place in potato cyst nematode (PCN) control strategies and the associated costs.
For agronomist James Lee, who oversaw the trials, the work confirmed that Velum Prime (fluopyram) is not a substitute for granular nematicides. “After three years, we have seen that Velum Prime plays an important role in complementing other products,” he says. “In this respect, our findings are in line with what Bayer has always said.”
Until last year, chemical pest control was based on the use of granular nematicides such as vidat (oxamil). Then came Velum Prime in the spring of 2019, which is based on the SDHI fungicide fluopyram, familiar to wheat growers who fight foliar diseases like septoria.
In the 2019 trial, both the best yield and the highest gross margin were obtained by consistently using Velum Prime and Vydate full rate rather than half rate granular. This approach incurs significant early-season chemical costs for growers, often the largest cost of crop protection.
“Initial costs are higher, but it was the most profitable option. He brought the highest yields and the best incomes.
Tests have shown that the nematode species present are exclusively G pallida, with a pre-planting test showing an initial cyst count of 27/g soil. On plots in two rows, each 12 m long, treatments were carried out using agricultural equipment: Velum Prime was applied on a seeder, and Vydate was applied in a bed treatment.
“All treatments had a positive effect on yield growth and final yield compared to untreated treatments, indicating nematode control,” adds Mr. Li. While the crop protection benefits of Velum Prime were slightly higher than Vydate when used alone, their consistent use resulted in significantly higher yields.
“This yield difference alone justifies using both products to their full potential,” he emphasizes. "The margin data also confirms this and reflects the nematode pressure on the crop." Otherwise, clear physiological benefits were recorded in all treated areas, with no effect of the treatment on dry matter content or the presence of internal defects.
There was also little difference in germination and haulm development between treatments, with all reaching 50% germination 31 days after planting. “As expected, plots that were better protected from the nematode experienced stronger plants due to higher product application rates.”
The only anomaly in the trial was that soil analysis after harvest showed that the ratio between the initial number of eggs (Pi) and the final number of eggs (Pf) did not change. "This was a surprise. Agrotechnical results suggested that the untreated plots would have a higher multiplication rate, but there was unlikely to be an increase on any of the treatments. We don't know how to explain it."
Velum Prime is a welcome addition to the weapon against potato cyst nematodes and arrived just in time, sums up James Lee of Produce Solutions.
Because the long-term future of granular nematicides is unclear, manufacturers should take every opportunity to try a new product and see if it suits them.