Effects of organic practices on Diaphorina citri dynamics and nutrient absorption of citrus trees.

摘要

Organic agriculture has increased dramatically over the last 15 yrs. As world trends towards more sustainable and environmentally-friendly production policies, more consumers seem to be interested and seeking for produce free of residues of chemical pesticides and synthetic fertilizers. However, the amount of scientific data available on sustainable perennial citrus production is considerably insufficient. The purpose of this project is to determine the effect of using organic practices such as use of biopesticides and different compost sources on citrus trees nutrient absorption and pest control. The nutrient leaf content of young grapefruit trees and their pest load were monitored over the active growing season. Three different compost sources were applied to the soil around the tree canopy. Pest populations were managed using different bio-pesticides commonly used by certified organic growers. Bio-pesticide and compost treatments were compared against a control group of trees not receiving compost and bio-pesticide. The control treatment was a group of trees not receiving compost addition and no bio-pesticide treatment. Random soil and leaf samples were taken over time to determine the effect of using organic practices on soil physio-chemical properties and plant nutrition. Population densities and fluctuations of Diaphorina citri were monitored weekly during the experimental period to evaluate the efficacy of different biopesticides or combinations in controlling D. citri populations at all developmental stages.