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June 6, 2000


less pesticides with Bt plants, archive 3036


>The choice between Bt plant and chemical pesticide *is* a false
Is! Isn't! We are retracing old ground. The facts remain that
chemical insecticide use on cotton dropped after the introduction of Bt
plants. Bt foliar sprays were promoted in Mississippi and elsewhere in
the late 1970s, when there was resistance to all of then available
chemicals, and the Bt sprays still flopped. By the way, much of the Bt
currently used is GM; Bt genes in killed Pseudomonas.

>Can you substantiate that claim? This is what I have in the GE Debate
Roberto, I find at least 3 clearly false claims in this section aone.

TimesOn cotton, see
Texas A&M University, report filed with US EPA for hearing on 21 May
1997 (Docket OPP-0478). I'll email you a copy if you want; I believe
that I have done so before.

See also


Times if
it is still up and


April 2000.

Economic Research Service, U.S. Department of Agriculture.

Economic Report No. 786 (AER-786).

Jorge Fernandez-Cornejo and William D. McBride, with contributions

Cassandra Klotz-Ingram, Sharon Jans, and Nora Brooks.

Contact: Jorge Fernandez-Cornejo, 202-694-5537. William McBride,




Adoption of genetically engineered crops with traits for pest
management has

risen dramatically since their commercial introduction in the

The farm-level impacts of such crops on pesticide use, yields, and net

returns vary with the crop and technology examined. Adoption of

herbicide-tolerant cotton led to significant increases in yields and

returns, but was not associated with significant changes in herbicide

On the other hand, increases in adoption of herbicide-tolerant soybeans

to small but significant increases in yields, no changes in net
returns, and

significant decreases in herbicide use. Adoption of Bt cotton in the

Southeast significantly increased yields and net returns and

reduced insecticide use.


> + GE crops will reduce the use of herbicides, insecticides and

>other chemicals.


> + BT: Prakash of Tuskegee University points out that before Bt

>corn was introduced, farmers controlled the corn borer with

>conventional insecticide sprays that are toxic not only monarch

>butterfly larvae but also other desirable, non-target species like

>lady bugs.

Not lady bugs

By cutting down on using these insecticides, Bt corn is a

>boon to beneficial species and the environment. "Ultimately the

>biggest benefit of biotech will be cultivating crops that use no

>herbicides, insecticides and fertilizers at all - and that even have

>nutrients and vaccines added, possibly at lower costs to consumers

>down the line," says Prakash.


> -- BT: Bt corn or chemical pesticides is a false choice. There

>are other alternatives: foliar Bt sprays, deploying natural corn

>enemies like wasps, proper timing of planting to avoid the rainy

>season, using conventional varieties resistant to the corn borer,

>detasseling, etc. In fact, many corn farmers do not spray field corn

>for corn borers. They see it as a waste of money, because the borers

>are inside the corn stem, and can't be reached by sprays. In their

>case, using Bt corn does not reduce chemical use.

Misleading if not false at least in the US. Corn growers spray
chemicals extensively in Nebraska and North Carolina, for example. At
least chemical sprays. By your own statements, how is Bt spray an
option if the borers are inside the stem? At least the chemical sprays
can kill the adult moths before they lay; Bt doesn't.


> - HT: Crops engineered to tolerate specific herbicides may

>encourage more liberal use of those herbicides. This has been

>anticipated by one manufacturer, who has applied to ANZFA

>(Australia-New Zealand Food Authority) to have the allowable residue

>of the herbicide glyphosate (Roundup) in foods sold in New Zealand

>increased by 200 times.

Blatantly false. See http://www.anzfa.gov.au/documents/res02_99.asp

"the residues of glyphosate on the soybeans as a result of the use of
RoundUp. All soybeans, whether obtained from a genetically-modified or
conventional crop must comply with the relevant MRL for that

commodity. Internationally, many countries accept the MRLs for
herbicides set by the Codex Alimentarius Commission, as

these represent generally acceptable levels of exposure when dealing
with commodities that are freely traded on global

markets. The Codex MRL for glyphosate in soybeans is 20 mg/kg. In
Australia, the current MRL for glyphosate in soybean is 0.1

mg/kg, which reflects the level that can be achieved under Australian
field conditions. Both levels are considered safe. There is

currently no application to increase the Australian MRL to 20 mg/kg but
consideration is being given to accepting the Codex

level in Australia for imported commodities in order to comply with
World Trade Organisation agreements. A change to the

MRL for soybeans is not required to grow or market RR soybeans in

In the production of conventional soybeans, the crop is generally
sprayed with a broad spectrum herbicide (such as RoundUp)

at the pre-emergent stage. In the USA, but not in Australia, there is
also a pre-harvest application which acts as a desiccant to

facilitate harvest and results in a higher level of residues. With RR
soybeans, the pattern of treatment of the crop is altered but

the frequency of use is not increased. In soybean agriculture in the
USA, there is reported to be a 10%-40% reduction in the

use of herbicides on genetically-modified soybeans"

In areas of the USA where GE-crops that

>produce their own insecticide are grown, pesticide use has not

>decreased. (See: "13 Myths about Genetic Engineering", Consumers for

>Education about Genetic Engineering, Dunedin Polytech, as posted by

>Deborah E Leech < on the SANET list)

False. It has done so at least for cotton. See above.


> - BT: Patent applications by Novartis of Basle, Switzerland

>the need for more pesticides to get the best out of GM plants.

False, as in the next comment, which both Kym Armytage and I have
challenged. If you stop spraying heavily, minor pests will appear but
the overall spraying is still less.


> -- BT: There is now confirmation from scientists in Georgia and

>neighbouring states that the 'stink bug' problem arising with Bt

>cotton crops is not confined to North Carolina, with farmers being

>advised to deploy new chemical pesticide regimes to combat the




Organic View, v.2 n.2, 29 Feb 2000: you take this as a credible
unbiased source?