Effect of Organic and Chemical Fertilizers on Growth and Yield of Hot Pepper, and Insect Pests and Their Natural Enemies

The effects of organic and synthetic chemical fertilizers on crop growth, yield and associated insect pests were studied for two varieties of hot pepper ( Capsicum chinense Jacquin (Solanaceae)): “Scotch Bonnet” and “Caribbean Red” in north Florida. Hot peppers were grown under three treatments: poultry manure; mushroom compost; or “Growers’ Practice”, (conventional pesticides and chemical fertilizers), with equivalent amounts of soil nutrients applied to all treatments. The Growers’ Practice treatment permitted use of conventional insecticides if insect pests exceeded economic thresholds. Results showed that although plant height and canopy diameter were significantly greater in the mushroom compost treatment for Scotch Bonnet, yields were not significantly affected by treatment or variety. The Growers’ practice treatment resulted in lowest plant height in Caribbean Red. Predominant insect pests found were the silverleaf whitefly, Bemisia argentifolii Bellows and Perring (Hemiptera: Aleyrodidae); green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphidae); bandedwinged whitefly, Trialeurodes abutilonea (Haldeman) (Hemiptera: Aleyrodidae); and western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Significantly more insect pests were found on Caribbean Red than on Scotch Bonnet, but in none of the treatments did pests reach economic injury levels. Therefore, insecticide treatment was not necessary during the seasons tested. Furthermore, the crops may be grown using relatively inexpensive organic fertilizers because the use of synthetic chemical fertilizers does not result in higher yields. Yields realized in the three treatments ranged from average to above average for both varieties of pepper. Findings are consistent with economic reports from other countries. We conclude that organic methods can be profitable for growers in Florida provided pests remain below the economic threshold levels.