Photos and text by Debbie Roos, Agricultural Extension Agent.
The broccoli variety ‘Arcadia’ was transplanted into the field on March 24. The farmer uses organic practices. Natural fertilizers including boron were applied based on soil test recommendations. The center of the broccoli heads are not maturing and some flower buds are turning brown. Approximately 75% of the crop is affected. This was also a problem on the later maturing heads in the first planting set in the field on February 16.
This is brown bead, a broccoli disorder that can be caused by poor growth, disease, or excessive temperature. It is typified by flowers that are small, turning brown, and not growing.
Research has shown that fast-developing broccoli plants tend to be less susceptible to brown bead. A study showed that broccoli under higher nitrogen application rates had less incidence of the disorder than plants under lower N rates. A regular supply of water also decreases the incidence and severity of brown bead.