How is Sacbrood typically diagnosed?

Sacbrood is a viral disease that primarily affects larvae in honey bee colonies. It is typically diagnosed when there is evidence of a swollen, watery sac within the larval cells, which is filled with viral particles. This distinct appearance signals that the larvae are infected and unable to develop normally.

When observing afflicted brood, beekeepers may find that affected larvae appear discolored and are often in a watery state, which contrasts sharply with the healthy, solid-looking larvae. The presence of this watery sac is a clear indication of the disease, making it a key diagnostic feature.

The other options do not align with the typical characteristics of Sacbrood. For instance, holes in capped cells are more associated with pest damage or lack of hygiene rather than viral infections. The heart-shaped pattern in mycelium suggests fungal issues, while dead brood with a black scale indicates other diseases such as American foulbrood. Each of these conditions presents unique symptoms, which is why recognizing the watery sac filled with viral load as a hallmark of Sacbrood is crucial for accurate diagnosis.