Several diseases and problems cause black or brown specks. Black rot may show up as V-shape yellow areas on the leaves that point to a vein. It may spread into the stems, which when cut may show a brown discoloration. The head may have many black specks, discoloration, and black veins. This is caused by bacteria that overwinter on plant debris, or reside in infected seeds. It can survive in the soil for 2 years. High temperatures and humidity help it to spread, and is easily transmitted by garden tools, insects, wind, splashing water, etc. If you suspect this is black rot, do not plant cole crops in that area for 2 or 3 years. Remove all plant debris each season, keep up with weeding, and buy certified disease-free seeds.
Black speck is a physiological disorder, not related to a bacteria, fungus, or virus. In this, tiny black specks appear in the interior of the curd, on the stems and flower stalks. You can see it when you break open the head, but they are not on the outer top of the head. Black speck can appear in warm weather during rapid growth, and may be related to a nutrient deficiency.
Downy mildew can also discolor heads. Sometimes cauliflower will develop black specks just as a part of aging, indicating that the head is past its prime.
Several diseases and problems cause black or brown specks. Black rot may show up as V-shape yellow areas on the leaves that point to a vein. It may spread into the stems, which when cut may show a brown discoloration. The head may have many black specks, discoloration, and black veins. This is caused by bacteria that overwinter on plant debris, or reside in infected seeds. It can survive in the soil for 2 years. High temperatures and humidity help it to spread, and is easily transmitted by garden tools, insects, wind, splashing water, etc. If you suspect this is black rot, do not plant cole crops in that area for 2 or 3 years. Remove all plant debris each season, keep up with weeding, and buy certified disease-free seeds.
Black speck is a physiological disorder, not related to a bacteria, fungus, or virus. In this, tiny black specks appear in the interior of the curd, on the stems and flower stalks. You can see it when you break open the head, but they are not on the outer top of the head. Black speck can appear in warm weather during rapid growth, and may be related to a nutrient deficiency.
Downy mildew can also discolor heads. Sometimes cauliflower will develop black specks just as a part of aging, indicating that the head is past its prime.