Nanoemulsion from Piper aduncum, Cymbopogon nardus, and Bacillus thuringiensis to Control Xanthomonas axonopodis pv. allii

Abstract

The bacterial speciesXanthomonas axonopodispvallii(Xaa)is an important pathogen causing leaf blight in shallots. The use of botanical pesticides with nanoemulsion formulations has become acommon alternative.Thisstudyaimstodeterminethecharacteristicsand optimumconcentrationofthemixtureofessentialoilofPiper aduncumandfragrantCymbopogonnarduswaste.Nanoemulsion formulations are made using spontaneous emulsification methods. Besides,testingBacillusthuringiensisstrainMRSNR3.1andits secondary metabolitestoxicity against Xaa was carried out by the diffusion method using paper discs to determine the diameter of the inhibition zone.The results demonstrate that allfourconcentrations,1%, 2.5%, 5%,and7.5%, couldcontrol Xaa bacteria. A concentration of 1% is consideredmoreoptimal than the otherthreeconcentrations in bactericidal effects against Xaa,as manifested in the formed clear zone (diameter of 3.17 cm).Besides,Bacillus thuringiensisstrain MRSNR3.1 and its secondary metaboliteswere also effective againstXaa afterfourdays of incubation with inhibition zones of 3.04 ± 0.44 and2.21±0.28,respectively.Hence,itisconcludedthat nanoemulsion at 1% concentration andBacillus thuringiensisstrain MRSNR3.1 have bactericidal properties that can be used to controlXaa