European sunflower moth Homoeosoma nebulellum Hübner is the most serious pest on sunflower and seeds. To better understand the relationship between plant flowering phenology and host plant resistance to H.nebulellum,experiment was conducted to evaluate infestation index of seed from 12 typical sunflower accessions in field. Results showed that sunflowers during R5. 1 to R5. 2 flowering stages( opened tubular florets accounting for10- 20% of the whole head) were damaged more heavily than those at other flowe...