The occurrence of, and damage caused by, root maggots on Chinese chives and integrated management techniques to control these pests
Author of the article:WU Qing-Jun1** YU Yi2 GU Xi-Shu3 LIU Feng4 SONG Dun-Lun5 WEI Guo-Shu6 HE Min7 LIU Chang-Zhong
Author's Workplace：1. Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; 2. Institute of Plant Protection, Shandong Academy of Agricultural Sciences, Jinan 250100, China; 3. Tianjin Institute of Plant Protection, Tianjin 300381, China; 4. Shandong Agricultural University, Tai’an 271018, China; 5. College of Plant Protection, China Agricultural University, Beijing 100193, China; 6. Agricultural University of Hebei, Baoding 071001, China; 7. Institute of Plant Protection and Environment Protection, Beijing Academy of Agricultural and Forestry Science, Beijing 100097, China; 8. College of Plant Protection, Gansu Agricultural University, Lanzhou 730070, China; 9. Institute of Plant Protection, Liaoning Academy of Agricultural Sciences, Shenyang 110161, China
Key Words： root maggot, Chinese chive, Bradysia odoriphaga, Bradysia difformis, occurrence and damage, integrated management
Abstract： Root maggots are serious pests of Allium vegetable crops, particularly Chinese chives. A national project approved in 2013 to address this problem included research on the biological and ecological characteristics of root maggots, their population dynamics, control methods, and integrated management strategies. With the exception of Gansu and Liaoning Provinces where B. difformis is the most common species, the predominant root maggot on Chinese chives is Bradysia odoriphaga Yang et Zhang. The population dynamics of root maggots in northern, northeastern, northwestern and eastern China were clarified using the yellow sticky trap method combined with investigating larvae in soil. Root maggots have strong cold tolerance but relatively weak heat tolerance and cause the greatest damage to crops in spring, autumn and winter. In summer, root maggots move to different crops and overwinter at a depth of 0-5 cm in soil as mature larvae. Because adults prefer black and brown, a black sticky trap was invented. Covering insect-proof nets with 50-60 mesh was effective in protecting chives against root maggots, moreover the growth of chives was also promoted. Methods for rearing the dominant natural enemy of root maggots, Coenosia attenuata Stein, in laboratories and releasing it in the field, were established. Entomopathogenic nematodes and Bacillus thuringiensis strains with high toxicity to root maggots and a control efficacy in the field of > 60% were identified. Ten relatively easy techniques, such as irrigating with ozonized water, reducing the application of insecticides, particularly the drench application of insecticides, were investigated. Technologies for the integrated management of root maggots were established according to local production methods and timing of infestation of chive crops. More than 5 000 farmers and agricultural technicians were trained. Obvious economic, ecological and social benefits followed.