Vol. 51—1997 - NorthEastern Weed Science Society

169
Potential ~pact of Herbicide-Resistant Crops on Specialty and Minor Crops
Leonard P. Gianessi 1
This papet'coversthe potentialimpactsof geneticallyengineeredherbicideresistant
cultivarsfor min9r crops.The paperfocusesprimarilyon vegetablessincegeneticallyalteringtree
and vine crops tojtolerateherbicidesis not likely to gain muchattention. The paper also discusses
impactson min01crops of the developmentof herbicideresistantfieldcrops such as soybeans.
The minot crop problemis fairlywell known. Thereis an absenceof herbicidesfor most
vegetablecrops. lOver70%of vegetablecrops lackeither preemergenceor postemergence
herbicidesthat provide effectivebroadspectrumweedcontrol. As a result,vegetablegrowers are
forced to use expensive handlabor or plastic to controlweeds. What's the potentialof
biotechnologytojprovidemore optionsfor minor crop vegetablegrowers?
I
Why aren't there moreherbicidesfor minor cropsright now? It's due to the high cost of
registrationand ~e potentialrisk of damagingcropsthat are worththousandsof dollars an acre.
The costs are high, the risksare high and the marketis small. Herbicidemanufacturershavelittle
interestin marketingherbicidesfor minorcrops even if farmershavea demonstratedneed. Will
bioengineeredplants offer a way out of thisproblem?
National!erbiCidesalesdata demonstratethe disparityin herbicidemarkets. Soybean
growers spend $ .5 billion a year on herbicides. Con. growersspendaboutthe same. Com,
soybeansand co onjustify the millionsof dollarsrequiredto developa new herbicideand gain
registration. Th~ nationalmarketfor potatoherbicidesis $32 million. Thus, an herbicidethat
would be a goodlfit for potatoesis unlikelyto be developedunlessit also has com, soybeanor
cotton use. All dther vegetablestotal$91 millionin herbicidesales. That's about 30 different
crops. These ardvery smallmarkets.
Some ha~e said that the U.S. doesn't really need anothersoybeanherbicide. There are 26
herbicideactiveingredientscurrentlyused in soybeans. There is not a lot of handweedingor use
of plastic in soybeans. Meanwhile,carrots,lettuceand peppershave three to six herbicides
registeredand itiuse. Soybeangrowershave numerouspre and post-emergenceherbicide
options. For jUs~ about any weedinfestingsoybeans.there are numerousoptionsfor control.
However, U.S. ~rowers are going to have anothermajor herbicideaddedto the soybeanweed
control arsenal./
Monsantohas developedglyphosateresistantsoybeans. Throughbiotechnology,soybean
plants have beeriengineeredto resistglyphosate. Soybeanplantswithoutthe resistancegene are
killed by glyphcrate applications. By plantingthe resistantsoybeanplants,growerswill be able to
go over the toprsoybean plantswith glyphosatefor_weedcontrol.
One of thereasonswhy soybeangrowersare likelyto adoptthe use of glyphosateis
potentialreduction of herbicidecosts. Currently,soybeangrowersaroundthe country spend $22
to $32 an acre fpr their herbicides. The use of glyphosatecouldpotentiallyreducethis cost to $8
i
1 Senior Research ~sociate, National Center for Food and Agricultural Policy, 1616 P Street, NW, Washington,
DC 20036. !