ASHS 2015 Annual Conference

Citrus production in Texas is primarily located in the four southernmost counties in close proximity to the Mexican border in the Lower Rio Grande Valley (LRGV).  The majority of fruit produced in this region is a variety of deep red grapefruit that is destined for the fresh market. The LRGV has a subtropical climate and calcareous soils ideal for producing sweet, red grapefruit; however, the industry is faced with many unique challenges associated with citrus production. In 2009 we were challenged to manage a devastating pest, the root weevil (Diaprepes abbreviatus) combined with Phytophthora spp. that invades damaged roots, while maintaining crop production and optimizing water use in a time of extreme drought. To address these issues we developed a promising planting strategy that interrupts the life cycle of the root weevil, effectively controlling populations and minimizing the risk of Phytophthora infection to roots, while providing optimal soil environmental conditions for plant growth and production.  Using a plastic mulch groundcover on young citrus trees planted on raised beds resulted in reduced water lost from the soil surface and maintaining water lower in the soil profile where roots occur, elevating soil temperatures while diminishing Diaprepes populations.  When compared to the traditional planting strategy of flat-bed production without groundcover, we found that this novel strategy increased plant height, trunk diameter and canopy perimeter.  We also found that there were a significantly lower number of Phytophthora propagules found in soil samples collected under the canopy of citrus trees in raised beds compared to those on flat soil.  Working in concert with a local citrus producer, a demonstration site has been established to exhibit these strategies and promote water savings and pest management at the on-farm level.