Impact of High-Density Planting and Enhanced Nutritional Program on HLB-affected Grapefruit

Abstract

Florida citrus growers have been using high-density planting and different soil and foliar fertilizer application strategies to compensate for the adverse effects of citrus greening or Huanglongbing (HLB). Recent studies indicated that high-density plantings and enhanced nutritional programs such as the application of controlled-release fertilizer (CRF) with higher micronutrient levels could mitigate disease symptoms and extend the tree life span of sweet orange (Citrus sinensis). Studies are limited to tree density and scarce literature is available about the effect of high-density plantings with the conjunction of soil and foliar nutrient application on HLB affected grapefruit tree health, fruit yield, and fruit quality in Grapefruit (Citrus paradise). A large-scale field trial was conducted from 2018 to 2020 at the UF/IFAS Indian River Research and Education Center (IRREC) in Fort Pierce, FL. The study evaluated tree planting density, soil micronutrient application, and foliar-applied micronutrients on grapefruit tree growth and fruit yield parameters, physiological response, and HLB incidence.