Effect of Well-timed Treatment of Fosthiazate Granule on Low Density Field of Sugar Beet Cyst Nematode, Heterodera schachtii Schmidt

Abstract

In Japan, the sugar beet cyst nematode, Heterodera schachtii Schmidt, was confirmed first in September 2017, on the roots of Brassica sp. cultivated in Nagano Prefecture. In response to this, as an emergency measure to eradicate H. schachtii and to prevent further infestation, multiple rounds of fumigant application were carried out. Cultivation of host crops was then resumed on fields where densities of H. schachtii cysts were observed to have lowered below detectable levels. However, H. schachtii cysts were re-detected in 14% of fields in which cultivation of host crops was resumed. This study was carried out to verify the effect of fosthiazate granules on recurrence prevention in fields in which farming was resumed and to determine appropriate treatment time. For this, nematicide was applied at different times to the low-density field of H. schachtii cysts, and its effect on the density was examined. We found a high control effect especially when the nematicide was applied to soil 7 days before transplanting the host plants.