Potential Benefits of Supplemental Calcium Additions for Sustaining Citrus Production and Quality

Citrus growers in South Texas make money primarily through the fresh market citrus varieties.  This citrus producing region is a subtropical environment with a high heat and humidity index nearly year round due to its close proximity to the Gulf of Mexico.  The control of citrus related pests that impact external fruit quality is of primary concern to South Texas citrus growers to prevent the down-grading of fruit to the juice market.  Of recent concern, Huanglongbing (HLB) or ‘greening disease’ as transmitted by the Asian Citrus Pysllid (ACP), was discovered in January 2012, in South Texas.  HLB disease has the potential to drastically and rapidly reduce citrus production for both conventional and organic citrus producers.  Populations of ACP are throughout the citrus producing region of South Texas, thus immediate measures that reduce ACP infestations to citrus trees is one method to limit the spread of HLB.  The objective of a serious of studies focused on supplement calcium additions to soil and foliage of citrus trees in high calcareous soil systems.  Field and laboratory studies were performed over the past three years to evaluate what impact supplemental calcium applications would have on ACP infestation levels to young citrus shoot flush.  Results have demonstrated a positive correlation between lower ACP infestations in trees receiving additional calcium application, regardless of whether the macro-nutrient is applied to the soil or to foliage.  These findings are encouraging for the long term sustainability of citrus production for both organic and conventional growers.