Weed Seed Contamination in Imported Celery Seeds

Abstract

In 2022-2023, a total of 83,532.4 kilograms of celery (Apium graveolens) seeds were imported into Thailand from the United States (29,647.2 kg), Mexico (28,897.5 kg), Italy (24,986 kg), France (1.2 kg) and China (0.5 kg). Twenty-seven consignments of celery seeds were randomly sampled according to the International Seed Testing Association (ISTA) standards and examined in the laboratory for weed seed contamination, followed by germination testing. Weed seeds of Polygonum bellardii were detected in four samples from the United States. Five weed species were detected in six samples from Mexico: Amaranthus viridis, Chenopodium murale, Echinochloa colona, Melilotus indicus and P. bellardii. Three weed species were found in fifteen samples from Italy: Helminthotheca echioides, C. album and Solanum ptychanthum. One sample from France contained P. bellardii, while no weed seeds was detected in sample from China. Among these, C. album is listed as a quarantine pest of Thailand, while C. murale, S. ptychanthum and H. echioides have not been previously reported in the country. Pest risk analyses may therefore be required to determine appropriate handling measures. All detected weed seeds were able to germinate under testing conditions. Field inspection in Tak and Chiang Mai provinces did not detect any quarantine pests.