Biostimulants Effects on Bell Pepper (Capsicum annum) Plant Growth, Fruit Yield, and Incidence of Fruit Disorders

In the southeast U.S., bell pepper can be subject to heat stress during harvest time (spring) or during crop establishment (fall). Crop biostimulants have been shown to increase crop yield and quality under adverse environmental conditions. The objectives were to determine the effects of plant biostimulants on plant growth, and fruit yield and incidence of physiological disorders of bell pepper grown in spring and fall seasons.  Study carried out at the University of Georgia, Tifton Campus, in the spring and fall of 2013.  Experimental design was a randomized complete block with five treatments (biostimulants) and four replications. Biostimulants were abscisic acid (1000 ppm ABA); MaxCel (6-benzyladenine; 1 mL/L); Screen Duo (aluminum silicate; 15 g/L); seaweed [brown alga, Ascophyllum nodosum (Phaeophycaceae)] extract (5 g/L), and untreated control (UTC). Cultivars were Wild Cat (spring) and Isla Morada (fall). Fruit graded according to USDA standards and weighed to determine yields. Number of fruit with blossom-end rot (BER) and sunscald were recorded. In the spring, southern blight (caused by Sclerotium rolfsii) severely affected bell pepper crop causing high plant mortality. In the spring, plant stem diameter was lowest in ABA treatment; marketable yield was highest in ABA and lowest in UTC and seaweed treatments. Yield differences were attributed to differences in fruit number. In the fall, stem diameter was greatest in seaweed and aluminum silicate treatments, while marketable yield was not affected by biostimulant treatments. Individual fruit weight and incidences of blossom-end rot and sunscald were unaffected by biostimulants in both spring and fall seasons. Effect of biostimulants on plant growth and fruit marketable yield was inconsistent and depended on the season.