The wintering density of Liriomyza chinensis (Kato) pupae was estimated as 154.7 individuals/m² on green onion fields in Nara prefecture. The wintering pupae of L. chinensis were considered to be living in the soil from late September until late March.
Soil fumigation with 30 kg/10 a dazomet was highly effective in controlling L. chinensis pupa without covering the ground with film. Application of 10 kg or 20 kg/10 a dazomet and then covering the ground with film was highly effective. As a result, dazomet was considered highly effective for control of the overwintering pupa of L. chinensis under the low-temperature condition.