Field Methods for Rapid and Noninvasive Diagnosis of Huanglongbing through Symptomatic Evaluation and Diagnostic Testing

Abstract

Huanglongbing (HLB) is a highly destructive disease that has inflicted significant damage to citrus orchards in major growing regions worldwide, resulting in significant reductions in production and posing a serious threat to the citrus industry.HLBiscausedbyagram-negative,uncultivablebacterium,CandidatusLiberibacterasiaticus,whichcolonizesthe phloem,andisnaturallytransmittedbyvectorinsects,suchastheAsiancitruspsyllid,Diaphorinacitri.This study will help to expand the knowledge on HLB in existing literature by focusing mainly on the incidence and diagnosis in different zones of Bahawalpur.The use of the pen test and iodine starch test to detect HLB provided a reliable and cost-efficient method for diagnosing the disease in the field. Symptoms expression was considered a fundamental criterion for HLB diagnosis, including leaf drop, stunting, mottling, and color inversion in fruits. The disease incidence ranged from30% ±1.15to44%±1.15acrossdifferentzones,withBahawalpurhavingthehighestincidence.Thesefindingssuggestthat some areas may be more susceptible to the disease than others, and further investigation is necessary to determine the underlying factors responsible for thisdistribution.