12/27/2022 - By Dr. Tom Reed

Field crop problems are often the result of a combination of factors. From nutrient deficiency to temperature change, to pests and disease, crop problems can cause significant economic consequences for producers.

Blossom End Rot

Blossom end rot is a disorder in vegetable crops, such as peppers and tomatoes, that have calcium (Ca) deficiency. Calcium is a required element for plants to grow normally and produce healthy fruits and seeds. Thus, blossom end rot results from a Ca deficiency in young, rapidly expanding fruit tissues and causes major production loss. However, it may be prevented with adequate fertilization and irrigation.

Calcium deficiency in fruits and vegetables results from either insufficient Ca in the soil solution, or insufficient amounts of Ca being delivered to the rapidly growing tissues. Calcium in the soil solution comes from soil mineral sources, fertilizer, and irrigation water.

Symptoms of Blossom End Rot

Blossom end rot symptoms begin as light discolored spot that then expand into a larger area, which begins to turn darker in color from colonization, typically by fungal species. Blossom end rot spots can be subject to infection from bacteria, and symptoms may occur at the blossom end of the fruit or on the side of the fruit.

Factors that predispose fruit to blossom end rot include:

-          Excessive fertilization, leading to a rapid increase in vegetative growth as Ca is preferentially moved to growing leaves, rather than fruits.

-          High soluble salt concentrations in soil solution around plant roots and inadequate irrigation, result in less water and nutrient uptake.

-          Damage to the root system by nematodes, diseases, or mechanical cultivation can also increase chances of blossom end rot.

Often, blossom end rot occurs when irrigation is irregular and soil Ca does not get carried to the developing fruit. More specifically, inconsistent irrigation programs with wet and dry cycles on sandy, well drained soils.

How to Reduce the Chances of Blossom End Rot

There are ways to reduce the likelihood of blossom end rot in a crop including:

-          Maintaining a consistent level of soil moisture throughout the fruiting cycle.

-          Utilizing an irrigation system that can supply adequate water especially during high stress periods of drought and wind. (Soil moisture monitoring technology can assist growers in providing adequate moisture for crop growing season.)

-          Avoid applying excessive nitrogen fertilizer to prevent excessive vegetative growth.

-          Provide sufficient soil solution Ca concentrations available to the crop plant. Foliar-applied Ca fertilizers are not likely to correct or prevent blossom end rot. Calcium ions are not actively mobilized from the leaf downward to the fruits.

-          Management of pests that can damage roots and preparing soil with limited compaction zones, that may restrict root growth, will allow for better water and nutrient uptake.

Reach Out to Your Harrell's Rep

Blossom end rot is not always a straightforward fruit disorder, in either cause or prevention. However, producers can minimize blossom end rot with optimal fertilization and irrigation management. Harrell's POLYON® fertilizer blends are engineered to provide nutrients over time at a predictable rate under specified conditions. To find the right POLYON® controlled-release fertilizer product for you, reach out to your Harrell's Rep.