Etiology, symptoms and prevention of chalkbrood disease: a literature review

ABSTRACT The fungus Ascosphaera apis, responsible for causing the chalkbrood disease of honey bees, is widely present in temperate regions of the northern hemisphere, but has also spread to other regions of the world such as Brazil. Although it is not usually lethal for the colony, it can reduce its population, hampering its development. This study is a review on the disease that presents a broad overview of its development, identification methods as well as ways to control it. Research shows that chalkbrood is associated with several factors and is most frequently found in colonies of Apis bees during the spring, when there is excess humidity and sudden temperature changes in the hive. Other factors such as viral or bacterial infection, the presence of the ectoparasite Varroa destructor, pesticide poisoning and poor nutrition of nurse bees can also affect its incidence and severity. Field diagnosis is made based on the presence of hardened mummified brood in the pupal stage, of white or black color, in the cells and entrance. Affected cells show dead pupae covered with white mycelia, resembling cotton, or hardened, dry and brittle, resembling chalk pieces, which originated the name. To date, there are no efficient methods to reduce the damage caused by chalkbrood. Genetic selection of bees with higher hygienic behavior and disease resistance is recommended.

摘要：引发蜜蜂白垩病（chalkbrood disease）的病原体为蜜蜂球囊菌（Ascosphaera apis），该菌广泛分布于北半球温带地区，且已扩散至巴西等全球其他区域。虽然该病通常不会导致蜂群死亡，但会削弱蜂群群势，阻碍其生长发育。本研究为该病害的综述性研究，全面概述了其发病过程、鉴定方法及防控策略。研究表明，白垩病与多种因素相关，多发于春季的蜜蜂属（Apis）蜂群，此时蜂箱内湿度偏高且温度骤变频繁。其他影响其发病率与病害严重程度的因素还包括病毒或细菌感染、体外寄生虫狄斯瓦螨（Varroa destructor）的寄生、农药中毒以及保育蜂营养不良。田间诊断可依据巢房及巢门口发现的蛹期硬化僵蛹进行，此类僵蛹呈白色或黑色。受侵染的巢房内，死蛹表面会覆盖状如棉絮的白色菌丝，或硬化为干燥易碎、形似粉笔的僵体，白垩病之名也由此而来。截至目前，尚无有效手段可减轻白垩病带来的危害，因此推荐选育具有更强卫生行为与病害抗性的蜂种。