Many introduced pests (=pathogens, pests, and weeds) are responsible for major crop disease epidemics. The estimated economic impact of introduced pests on Africa's agricultural sector was up to US3.6trillionperyear.Seedtransmissionofpests,alongwiththeinternationaldistributionofplantpropagationmaterials,isamajorriskforgermplasmdistributionactivitiesofIITA.Asapestriskmitigationmeasure,IITAestablishedGermplasmHealthUnit(GHU)tofacilitategermplasmproductionfreeofharmfulquarantinepestsforconservationandinternationaldistributionandcomplywithnationalandinternationalquarantineprocedures.GHUusesamultidisciplinaryandmultistageprocessforensuringphytosanitarysafety:seedhealthtestingusingarangeofdiagnostics.Between2017−21,GHUtestedabout700,00samplesof15speciesandeliminated810 per sample (US$ 5.6 million over five years). GHU distributed safe germplasm to 69 countries and prevented the transboundary spread of quarantine pests with IITA activities, making the most important contribution to national biosecurity