Category Hive Disease Diagnosis & Pathogen Differentiation

Most brood problems look alike from three feet away: a patchy pattern, some sunken cappings, a few dead larvae. What they mean depends on details that take a minute to check. A spotty pattern with multiple eggs per cell or drone brood in worker cells is a queen problem, not a disease. Sunken, perforated cappings over discolored larvae point toward a brood disease, though hygienic bees also open cappings to pull out mite-damaged pupae, so check underneath first.

Smell and texture separate the foulbroods: European foulbrood gives a sour smell and twisted, yellowed larvae that die before capping, while American foulbrood smells foul and a matchstick pushed into a dead cell draws out a brown rope. Dead larvae in uncapped cells at the nest edge after a cold snap are more often chilled brood than infection. The adult-bee cases get the same treatment: trembling, hairless black bees may mean chronic bee paralysis virus or a pesticide hit, and dysentery on the hive front does not by itself confirm nosema.

When field signs will not settle it, the section covers lab testing and when to call an apiary inspector. Quarantine anything suspect first; a diagnosis can wait a week, spread cannot.

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