Plant Biotech Blog

C Kameswara Rao
Foundation for Biotechnology Awareness and Education, Bangalore, India
pbtkrao@gmail.com

Technologies come with some concomitant and some consequential benefits, both of which should be taken together in assessing the total benefits that accrue.   No technology is risk free.   Benefits of a technology should hence be weighed against minimal and acceptable risks and a favourable cost-benefit ratio.  

Risk assessment, mitigation and management are at the heart of regulatory processes.   Planting a non-Bt refugium along with Bt crops is a means of mitigating the risk of acquired resistance, and so is gene stacking (see the article ‘Transgenic Bt Technology: 2. Bt Crop varieties’ in this series). 

Stakeholder acceptance of a technology is rooted in a rational and balanced projection and not in hype.   Factual information will enhance the credibility of the establishment and help the consumer take educated and lasting decisions.

Concomitant benefits of Bt technology:  The most direct and the most important benefit of Bt technology is the control of the most damaging pest of particular crop, such as the American bollworm of cotton, stem borers of rice and corn, rootworm of corn, Colorado beetle of potato or stem and fruit borers of aubergine (brinjal).   As systemic pesticides, Bt proteins take care of these pests.   The other pests, on which Bt proteins have little or no effect, need to be controlled by pesticide application, preferably as a part of Integrated Pest Management (IPM) practices.

Bt technology imparts only tolerance of the targeted pest of a particular crop and not total resistance to it.  In view of the variation in the expression of Bt genes, due to various internal and external factors (see the article ‘Transgenic Bt  Technology: 4. Variation in Gene Expression, in this series), two or three pesticide applications are needed, against even the targeted pest, such as the bollworms of cotton, instead of the usual 10 to 20.   Even so, in a country like India, where over 50 per cent of pesticide application is on cotton, Bt technology results in a very substantial savings on pesticide costs and labour costs associated with pesticide application, provided the farmer does not resort to ill-advised or panic spraying.

A report from ISAAA (Brief No. 37, 2007) has reported diverse benefits from GE crops over a period of about 12 years of commercialization.  In India, from 2002 to 2007 there was an increase of farmer profits between 50 to 110 per cent, with yield increase between 30 to 60 per cent.  There was about 50 per cent reduction in pesticide usage.

Significantly, suppression of cotton bollworm in multiple crops in areas with Bt cotton was reported from China (Science, September 2008).

Optimal cultivation practices are mandatory:  Any crop should be grown under optimal conditions to obtain the best benefits from the new technology.   Although cotton is hardier than many other crops, it performs satisfactorily only under irrigation.   In India, cotton is often grown under near impossible conditions, as farmers are lured into growing a cash crop, irrespective of the inappropriate infrastructure, and suffer disastrous consequences.   The Government of Andhra Pradesh, India, rather unsuccessfully advised the farmers to avoid growing cotton on red soils, particularly as a rain fed crop.  A long time advice to grow cotton only in areas with the average rainfall of more than 60 cm per year, uniformly distributed throughout the crop season, is largely unheeded.   In many developing countries, the record of both the advice given to the farmers and of farmers taking it seriously, is dismal.  

Consequential benefits of Bt technology:  Bt technology’s consequential benefits are:

a) a healthy crop, more biomass and more yield;
b) reduced risk to farm labour involved in pesticide application; in the developing countries several thousand farm workers suffer or even die, due to unintended pesticide poisoning;
c) far lower concentrations of pesticide residues on the produce and in the environment;
d) reduced exposure of non-target organisms in the environment to pesticides, and so a better conservation of biodiversity; and
e) the Bt farmer experiences a far lower tension and is certainly better off with Bt technology than the earlier scenario of ‘spray and pray’.

What is not to be expected of Bt technology:  Bt technology has no role to play in the following areas:

a) Yield: Bt technology has no gene based influence on crop yield; nevertheless, there is a substantial increase in yield due to prevention of loss of the crop produce caused by the pests; Bt farmers in India earned Rs. 6,000 (about US$ 135) more per acre, than the non-Bt farmers during the last season (ISAAA (Brief No. 37, 2007);
b) Seed germination: failure of seed to germinate is often mischievously attributed to Bt technology; causes for the failure of seed germination lie in the varieties or cultivation practices or environmental factors; the percentage of germination of the seed of a Bt variety would be about the same as that of its isogenic;
c) Non-target pests:  Bt technology is specific pest targeted and has little or no effect on other pests;
d) Diseases:   Bt technology does not cause or control any viral, bacterial or fungal diseases; such diseases as the viral leaf curl prevalent in northern India or the physiological disorder para-wilt that occurs after a heavy rain fall preceded by drought conditions, are erroneously or deliberately attributed to Bt technology. 

It is a compulsive habit of the antitech activists to repeatedly attribute farmer suicides in India to the failure of Bt cotton crop.  A comprehensive review on the issue (October 2008) found no evidence in support of the allegation and it even pointed out that the number of suicides has actually come down after the introduction of Bt cotton cultivation. 

Other articles in this series:
TRANSGENIC BT TECHNOLOGY: 1. BACILLUS THURINGIENSIS, BT PROTEINS AND TOXINS

TRANSGENIC BT TECHNOLOGY: 2. BT CROP VARIETIES

TRANSGENIC BT TECHNOLOGY: 3. EXPRESSION OF TRANSGENES

TRANSGENIC BT TECHNOLOGY: 4. VARIATION IN GENE EXPRESSION

TRANSGENIC BT TECHNOLOGY: 5. SUBSTANTIAL EQUIVALENCE OF TRANSGENICS AND THEIR ISOGENICS

TRANSGENIC BT TECHNOLOGY:  6. BIOSECURITY

January 1, 2009