Abstract: 【Aim】 The aim of this study is to ascertain the taxonomic status, occurrence and damage characteristics of the maggot newly found in Xingtang County, Hebei Province, northern China, which has caused severe injury to corn seeds and seedlings. 【Methods】 The maggots collected from damaged corn field in Xingtang, Hebei, were reared in the laboratory. The morphological characteristics of different developmental stages were described. The maggot was identified by both morphological and molecular methods. The damage of this maggot to corn seeds and seedlings in the spring corn fields with different planting patterns in Xingtang, Hebei, including the corn monoculture field applied with decomposed organic fertilizer, the corn monoculture field applied with non-decomposed organic fertilizer, the corn-Chinese cabbage rotation field applied with decomposed organic fertilizer and the corn-Chinese cabbage rotation field applied with non-decomposed organic fertilizer, were investigated by random sampling survey method. 【Results】 The morphological characteristics of different developmental stages of the unknown root maggot collected in fields and then reared in laboratory were basically identical to that of the reported Delia platura. The COI and Cytb gene sequences of the root maggot show 99% nucleotide sequence identity with those of D. platura, respectively. Therefore, the root maggot which injured the corn seeds and seedlings was identified to be D. platura both by morphological and molecular methods. Field survey results showed that D. platura caused more serious damage in the corn-Chinese cabbage rotation field applied with non-decomposed organic fertilizer than in other fields. Injured corn seeds could not germinate and injured young seedlings wilted and died. The total percentage of both corn seeds and seedlings injured by seedcorn maggots was 39.33%, and the maximum larval number per plant was eight. 【Conclusion】 It is the first report on D. platura infesting corn seeds and young seedlings in China. The damage risk by D. platura is very high for the corn-Chinese cabbage rotation field applied with non-decomposed organic fertilizer.

Key words: Delia platura, corn, insect pest, damage, morphology, molecular identification, prevention technology