Stem-end rot (SER) caused by Lasiodiplodia theobromae is a major postharvest disease of mango. To better understand the occurrence of multifungicides resistance in field populations, the sensitivity to five fungicides was investigated in 224 L. theobromae isolates collected from the mango growing region of Hainan Province in 2014–2018. The biocontrol activity of Bacillus amyloliquefaciens HBR-2 against resistant phenotypes of L. theobromae was evaluated using in vitro and in vivo tests. Our studies have established the baseline sensitivity of L. theobromae to difenoconazole, prochloraz and iprodione. Most isolates tested were sensitive to difenoconazole, prochloraz and iprodione. The overall resistance frequencies for difenoconazole, prochloraz and iprodione were 24.11, 15.18 and 1.34%, respectively. In addition, the overall resistance frequencies of L. theobromae for carbendazim and pyraclostrobin were 71.43% and 57.14%, respectively. In Hainan, 16 fungicide-resistant phenotypes were detected: 29.02, 60.27, 7.14, and 0.45% of the isolates were resistant to one, two, three, and four fungicides, respectively. The novel isolate B. amyloliquefaciens HBR-2 was found to have strong antagonistic activity against different resistant phenotypes of L. theobromae. The cell culture broth was the most effective treatment for controlling mango fruit rot in vivo. Multifungicide-resistant isolates of L. theobromae were widespread in Hainan. Biocontrol could be a valuable additional tool to manage the SER of mango fruit in the future. These findings would be useful in designing and implementing fungicide resistance management spray programs for the control of SER in mango.

Lasiodiplodia theobromae引起的茎端腐烂（SER）是芒果的一种主要收获后疾病。为了更好地了解田间种群对多杀菌剂的抗药性，在2014-2018年从海南省芒果种植区收集的224株梭菌中，对五种杀菌剂的敏感性进行了调查。使用体外和体内试验评价了解淀粉芽孢杆菌HBR-2对Theobromae耐药表型的生物防治活性。我们的研究建立了L. theobromae的基线敏感性地芬诺康唑，丙草胺和异丙隆。测试的大多数分离株对苯非那康唑，丙草胺和异丙洛酮敏感。地芬诺康唑，丙草胺和异丙嗪的总抗药性频率分别为24.11、15.18和1.34％。另外，Theobromae对多菌灵和吡菌胺酯的总抗性频率分别为71.43％和57.14％。在海南，检测到16种抗真菌剂的表型：29.02、60.27、7.14和0.45％的分离株分别对一种，两种，三种和四种杀真菌剂具有抗性。发现新的分离的解淀粉芽孢杆菌HBR-2具有对Theobromae的不同抗性表型的强拮抗活性。细胞培养液是控制芒果果实腐烂最有效的方法。耐多杀菌剂的Theobromae分离株在海南广泛分布。生物控制可能是将来管理芒果果实SER的有价值的附加工具。这些发现对于设计和实施用于控制芒果中SER的杀真菌剂抗性管理喷雾程序很有用。