Hi, signs of bud rot include discoloration of the buds, a musty smell, and soft, mushy textures. If they are only white or extremely light, it could simply be that it's the lower buds where no light reached.
High humidity:
Cannabis buds are particularly susceptible to mold when humidity remains high for extended periods. A relative humidity of over 50-60% during the flowering phase can create ideal conditions for the development of bud rot. Additionally, nighttime condensation caused by cooling air can increase moisture and promote fungal infestation.
Lack of air circulation: Poor ventilation leads to stagnant air and increases the likelihood of mold formation. Cannabis buds that grow close together are especially at risk. Without sufficient air movement, moisture gets trapped in the buds, creating a perfect environment for the fungus. Therefore, positioning fans and designing the grow space or growing area is crucial.
Temperature: Warm temperatures combined with high humidity encourage the growth of bud rot. Temperatures between 18-25°C are ideal for the fungus. In warmer climates or poorly insulated grow rooms, temperatures can rise further, accelerating fungal infestation. Also, temperature fluctuations that lead to dew and condensation can promote fungal growth.
These are the main causes, but there are more.