Maize: the gift of the gods

Uwe Rabe, Poduct Manager of Folicur at Bayer CropScience and organizer of the symposium, welcomes the participants.About hundred international experts took part in the Fusarium symposium at Bayer CropSience’s headquarter in Monheim,Germany.and Chiara Faenza of COOPItalia spoke for the retail trade.Irrespective of whether theydiscussed the additional costsincurred, or various initiativesto reduce mycotoxin levels,each of the speakers basicallyaddressed the same question:how do we meet legal requirementsin practice, whilst remainingeconomically competitive?And Diarmuid O’Connorpointed out that if tolerancesfor DON contamination are toolow, they can have the wrongeffect: „For baby foods, its notonly the tolerances for DONthat are considerably lowerthan those for the “normal”(adult) consumer: residue limitsfor other substances are alsomuch more stringent. Cerealcommodities offered on theopen market simply do notmeet these lower limits – so wehave to work with contractgrowers. However, whereaslevels of, for example, heavymetals are relatively easy topredict, this is not the case formycotoxin residues. If our contractgrowers can’t controlFusarium reliably in theircereal crops, then we have difficultyin sourcing, and as aresult we have to raise theprices of our baby foods. But ifbaby food becomes too expensive,parents tend to give theirchildren „adult food“ – in otherwords food from commoditiesfor which the considerablyhigher limits for adults apply.This situation cannot be in anybody’sinterest.“It emerged that a centralproblem facing those involvedin the food-production chain isa combination of cumbersomeand inadequate analytical andcontrol procedures. Kemperexpressed it from the farmer’spoint-of-view thus: „We don’tyet have a rapid, standard andreliable test for measuringDON-content. But we can’twait around for two days duringharvesting in order toobtain reliable values! We needto know for sure whether thecereal crop can be used forfood or animal feed, or whetherwe have to store it separately.“The need for such tests wasindirectly confirmed by ArtSchaafsma of the University ofGuelph, Canada. His studieshave shown that, for example,post-harvest determination ofthe proportion of Fusariumdamagedkernels (FDK) byoptical means is highly subjective.Moreover, according toSchaafsma, the level of correspondencebetween the FDKvalueand the actual mycotoxincontent – in this case, theDON-value – is not particularlyhigh. Therefore he, too, calledfor a reliable but practical testmethod to be established.Of course it would be best toprevent Fusarium infection(and thereby contaminationwith mycotoxins) altogether, orat least to limit its severity. Allof the speakers agreed thatbecause infection is influencedby a variety of factors, the onlyreal chance of achieving this isthrough integrated crop management(ICM).The second half of theSymposium was given over toresearchers from various countriesand continents, who presentedthe results of their studies,and described initiativesbeing taken in their countries.Isolde Häuser-Hahn, a researcherin the area of FungicideBiology within BayerCropScience, set the scenewith a presentation on the lifecycleof Fusarium spp. She alsodescribed the laboratory methodsthat are used to measurefungal growth, and to determinethe efficacy of fungicidesagainst Fusarium. Assessmentsof fungicidal activity andmycotoxin analysis are linkedwith field trials, in which theincidence of Fusarium infectionand possible contaminationof seeds with mycotoxinsare analysed. Alongside microscopyand a range of other conventionalmethods, a recentlydevelopedtechnique, MIPS ®1(Multiple Imaging Plant Stress)is also used to obtain non-invasiveimages and measurementsof photosynthetic activity inthe ear or other plant parts.This allows an estimate to bemade of the metabolic penaltyresulting from Fusarium infection.MIPS ® can also be used toshow how fungicide treatmentcan alleviate this loss of photo-1 = registered trademark of the PlantResearch International Institutes,Wageningen, NL1/05 COURIER 15