UVI Research and Technology Park

Crop Diversification Complexity and Pest and Beneficial Organism Communities

Crop Diversification Complexity and Pest and Beneficial Organism Communities in Humid Tropical and Sub-Tropical Climatic Regimes  


Carlene Chase, University of Florida, cachase@ufl.edu

Stuart A. Weiss sweiss@live.uvi.edu

Danielle Treadwell ddtreadw@ufl.edu

Robert McSorley mcsorley@ufl.edu

Oscar Liburd oeliburd@ufl.edu

Marilyn Swisher mesw@ufl.edu


The warm, humid climate in Florida, the US Virgin Islands, Puerto Rico, and other subtropical US states and territories is both an advantage and a disadvantage for vegetable producers. The tropical/sub-tropical climate permits year-round cropping. mild winters in sub-tropical regions and the lack of a winter cold season allow pests to persist from season to season. In addition, pest species occur throughout the region that do not persist outside tropical and sub-tropical habitats. Similarly, the high precipitation regime characteristic of the region encourages year-round persistence of many pest populations. Insect, weed and nematode populations in organic vegetable cropping systems may be effectively managed through crop rotation, intercropping, and cover crop management.


  • Evaluate the impact of selected crop rotation, cover crops, and intercrop systems on growth and yield of organically produced vegetables.
  • Evaluate the effects of the selected systems on the population dynamics of insect pests, beneficial insects, weeds, plant pathogenic nematodes, and to conduct simulation modeling of the dynamics of selected populations to explore how the experimental treatments may be affecting demographic parameters of the populations.
  • Assess soil and crop nutrient status in order to minimize the occurrence of crop macronutrient deficiencies and to correlate pest density and diversity with changes in crop and soil nutrient status.
  • Disseminate the research findings to local service providers, especially extension personnel, who work with organic farmers and farmers interested in transition to organic production, and to organic and transitional farmers.


The long term goal of this project is to develop strategies using cover crops, crop rotation and intercropping to maintain soil quality and reduce pest pressure in organic vegetable cropping systems in humid tropical and sub-tropical climatic regimes.

Anticipated Outcomes and Benefits

Production systems that include cover crops during fallow periods benefit from reduced nitrate losses due to leaching, reduced soil erosion, and increased organic matter and related effects on soil tilth and cation exchange capacity.  Agroecosystem diversification can maintain soil nutrient pools, project soil quality, provide improved pest suppression, and enhance ecosystem services. 


This project was a multi-institutional project.  The University of Florida (UF), Gainesville is the lead institution.  The University of the Virgin Islands (UVI) is collaborating and Florida Organic Growers and Consumers, Inc. (FOG) is cooperating.


  • Funded through the USDA-IOP Program

University of the Virgin Islands
Agricultural Experiment Station      
RR 1 Box 10,000                            
Kingshill, VI 00850        
Telephone: (340) 692-4020 Fax: (340) 692-4035