Syngenta Crop Protection UK Ltd
Increasing yield and improving quality in processing potatoes
24/11/2009
Potato growers could increase yields and improve the fry colour of processing crops with targeted control of free living nematodes and soil borne diseases. First results from a new series of trials by Syngenta and JP Agronomy have shown the seed bed combination of Amistar and Nemathorin can eliminate internal defects and improve processing quality.
)
Combination of Amistar for control of soil-borne Rhizoctonia and Nemathorin to counter free living nematodes have increased yields and quality in Norfolk processing crops
Trials have repeatedly shown the control of free living nematodes and Rhizoctonia leads to more even crop development and more consistent tuber maturity at harvest, reported Syngenta Potato Manager, Tom Whitworth. “The latest JP Agronomy trials in Norfolk have shown that where nematodes are reduced with Nemathorin treatment, the crop develops more evenly. The results show improvements in yield, fry colour and processing quality. This has the potential to improve results across all processing crops.”
Furthermore, the 2009 trial revealed internal defects in tubers were reduced from over 12% in untreated plots, to just 5% with Amistar alone and less than 4% with Nemathorin. “In plots where the Nemathorin and Amistar treatments were combined, the internal defects were completely eliminated,” added Mr Whitworth. “The level of tuber damage in the untreated crop would have seen the sample rejected for premium processing markets.”
The trials have also shown the Nemathorin and Amistar treatments help crops establish quicker and maintain ground cover for longer. In a crop of Hermes, for example, the treated plots achieved 90% ground cover a week ahead of untreated plots and retained over 55% ground cover at the end of August, when untreated plots had rapidly fallen away to 40% cover. Across a range of varieties, the treatments consistently produced more stems per plant.
Amistar treatments can retain healthy crop growth for longer, to boost yields and more consistent processing crop sugar levels (below)
)
)
Reducing the damaging effects of free living nematodes with Nemathorin can also protect crops from early die back caused by Verticilium wilt
Mr Whitworth reported whilst the 2009 trial yield data has yet to be assessed, in a similar trial in 2008 across 18 different processing varieties, the Nemathorin treatment for free living nematodes produced an average yield increase of over 10 t/ha, at 64 t/ha compared to 53 t/ha in the untreated plots. In some varieties the combined Nemathorin and Amistar application increased yield by nearly 30%.
The average yield increase was typically worth over £1050/ha in extra return, with yield increases in some varieties equivalent to 20 t/ha from Nemathorin treatment alone calculated to increase returns for growers by around £2100/ha.
The results clearly identified the severe damage being caused by the free living nematodes and the high yield responses to a soil-borne fungicide, even where there was no history of Rhizoctonia in the field and no visible signs of the disease in the growing crop. It also highlighted the different varietal responses to the affects of the nematicide and fungicide treatment from the more susceptible crops.
John Purslow of JP Agonomy advises the feeding activity of free living nematodes in high numbers can seriously affect emergence, root development and plant vigour, resulting in significantly reduced yields. “More vigorous varieties, such as Maris Piper, may be able to outgrow the effects and recover sufficiently with minimal loss, but on naturally less vigorous crops losses could be significant.
“If the nematodes also transmit Verticilium wilt, the affected plants will die back with a higher proportion of immature tubers, with higher sugar content resulting in inconsistent fry colour in the processing crop.”
Read more about using Amistar to combat potato soil diseases
