Our earlier report (Mar-2015) demonstrated the induction of new flush, flowering, reduction in fruit drop, and mobilization of starch in stem tissue of HLB-infected trees following the spray application of 10 �M strigolactone (SL) in greenhouse trees. Further investigation on the ultrastructural anatomy of citrus fibrous roots revealed that roots are infected very early as evidenced by the deterioration of phloem tissue in young �tertiary� roots. We classified the fibrous roots as primary, secondary, and tertiary roots. Symptoms in HLB-infected primary and secondary fibrous roots are uncertain as in the case of foliage tissue e.g., vascular bundles of the same tissue showed normal functional phloem while others showed blocked and disintegrated phloem. Similarly, accumulation of starch in root cortical tissue is uncertain. Within the same tree, some roots samples showed accumulation of starch while other are completely devoid of starch accumulation. SL application improved the storage of starch in root cortical tissue and generated more functional phloem in HLB-infected trees. SL treated plants showed more roots growth. Roots appear healthy and enriched with new young roots. HLB-infected roots appeared small and dark brown in color. SL application significantly delayed fruit abscission in green house grown trees. At this time, fruits are larger in diameter and remained intact on trees.