黑森瘿蚊的生物型组成及其对疫情流行的影响

The Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae), an important pest of wheat throughout the most part of the wheat growing regions in the world，is a quarantine pest in China, and has been controlled for 30 years in Xinjiang. Resistant wheat varieties have been proved the most reliable and economical form of management for the Hessian fly. However, the continued development of virulent biotypes in response to selection pressure imposed by widespread use of resistant cultivars poses great threat to the permanence of resistance. To date, 16 bitoypes have been identified overseas but none has been studied and reported in China. The epidemic occurrence of the Hessian fly in recent years in local wheat-growing regions has resulted in a great urgency to identify and monitor the shift of biotypes frequencies of the fly. Our objectives are: 1) to determine the biotype composition in local regions based on their virulence on all known Hessian fly resistance genes, H1-H32, and Hdic; 2) to find reliable approch to identify biotypes based on DNA markers; and 3) to understand the impact of biotype compositions on the population dynamics of the fly based on evaluating correlations between the resistance of wheat cultivars and biotype status, between population size and the biotype status. These results will provide useful information for improving control strategies for the pest.

黑森瘿蚊Mayetiola destructor (Say) 是世界主要小麦产区的一种重要害虫，我国发生于新疆，为重要的检疫性害虫，近30年来一直受到严格控制。近年来在局部地区再次暴发，疫情扩散形势严峻。抗虫品种利用是控制黑森瘿蚊疫情最重要的措施，但新生物型的出现对抗虫品种的有效利用构成严重威胁。进行黑森瘿蚊生物型的鉴定与监测，对有效利用抗性品种与控制黑森瘿蚊疫情至关重要。迄今为止，国外已鉴定了16种生物型，但国内尚未对生物型开展研究。本项目拟通过分析新疆疫区黑森瘿蚊种群对已知33种抗性基因的致害性，明确种群的生物型组成，为抗性品种利用提供依据；对已知生物型进行分子遗传多样性分析，探索分子标记在生物型鉴定中的可行性，为低虫口密度下进行生物型快速鉴定奠定基础；通过分析各生物型的危害地位与小麦品种抗虫性、种群规模间的关系，了解生物型组成对疫情发生的影响，为制定疫情控制对策提供理论依据。

黑森瘿蚊 Mayetiola destructor (Say) 是世界主要麦产区的重要害虫，在我国新疆局部分布，为重要的检疫性害虫，近 30 年来一直受到严格控制。近年来在局部地区再次暴发，疫情扩散形势严峻。摸清黑森瘿蚊的疫情发生动态和原因，明确黑森瘿蚊的生物型及其分布，对有效利用抗性品种与控制疫情至关重要。本项目通过田间普查和定点观察，调查了黑森瘿蚊的分布范围和发生特点，分析了疫情发生原因；利用4种抗性品种（分别携带H3、H5、H6和H7H8基因）鉴定了2个地理种群的生物型组成。结果表明，黑森瘿蚊目前主要分布于温泉县和博乐市，以春季世代危害为主，在温泉县春小麦、博乐市冬小麦上发生严重；导致疫情发生的主要原因是小麦敏感品种大面积种植、适宜的气候条件（尤其是4、5月温湿度）和防治措施不到位。在温泉和博乐麦田共发现GP、A、B、C、E、F、G、J和L等8种生物型，其中E、G在种群中的比例超过60%，GP在温泉、博乐种群中分别占15、18%，L型低于2%，其他生物型在各种群的比例在3%~8%不等。此外，建立了温泉、博乐2个实验室种群。研究结果对于进一步明确黑森瘿蚊疫情的发生的动态、评估黑森瘿蚊种群对已知基因的致害性及小麦品种的抗虫性，进而深入了解疫情发生机制与制定疫情控制对策奠定了基础。