Do we need Insect Resistant GM crops?

Learning from Bt cotton and Non Pesticidal Management Experiences

Vidarbha region in Maharashtra is witnessing deep agrar- ian crisis. The recently released National Crime Records Bu- reau Report documented 3146 farmers’ suicides during 2013 in Maharashtra adding up to 60,750 farmers’ sui- cides in the last 19 years and most of them are from the Vidarbha region. Another salient feature of all these farmers are they all are growing cotton in rainfed areas. While cot- ton itself is not new to the region, what changed in the last twenty years is the shift towards Hybrid American Cottons which need deep and fer- tile soils with better access to irriga- tion while the region has a mix of shallow soils and irrigation is less than 20% on aver- age. These cottons required more inputs there by increasing the costs of cultivation. The risk of failure also increased as these are not better adapted to the situations and changing climate. The Bt cotton hybrids which were introduced 12 years back have made the situation worse. The input costs and the frequency of crop failures have increased. Resulting in more and more suicides. Near about 30% of the total farmers sui-

cides are reported from this region. Gradually cotton has re- placed most of the other crops and today this entire region has become monoculture of cotton and soybean replacing millets and other pulse and oilseed crops which were tradi- tionally grown here.

For example, the Yavatmal district has only 10% under irrigation and several reports from the Planning commission’s report in 2007 to the latest report by National Bureau of Soil Survey and Land Use Planning (NBSSLUP) have pointed out that less than 50% of the soils are suitable for growing Bt cot- ton hybrids. The state governments have not made any initi- ation to address the problem. A shift towards better cropping systems and agronomic management is essential to make the farming more ecologically and economically sustainable. bel Even a pest management strategy, insect resistant Bt crops are not a solution. The toxin production in the plant all through the season poses severe threat to the ecological bal- ance and increases the selection pressure resulting in resist- ance in insects. The field reports from farmers, scientists and even company suggests that Pink Boll Worm has developed resis- tance to Bt cotton in Gujarat in 2008 itself. Last two years, farmers and scientists are also reporting similar trends with American bollworm helicoverpa in other states too.

While credible alternatives Non-Pesticidal Manag ement (NPM) and organic farming are always ignored. The experi- ence of these farmers suggests that widespread use of such GM crops violates the principles of sound pest manage- ment. The insect resistant GM crops even violates the basic prin- ciples of Integrated Pest Management (IPM) though some suggest them as part of IPM.

These strategies are based on the farmers’ own knowl- edge, management skills and labour, rather than external farm inputs. Their demonstrated effectiveness shows that farmers can manage insect pests successfully and affordably without resorting to chemical pesticides -or to insect-resist- ant GM crops.

Weighing the costs

It is generally accepted that under Integrated Pest Man- agement (IPM), insecticides should be applied only when the projected cost of damage from pests is greater than the esti- mated cost of control measures, and only after all other effec- tive insect-control techniques have been consid- ered.

Furthermore IPM practitioners look at the entire range of pests associated with a crop, rather than individual insect spe- cies. They seek to understand all the factors regulating pest populations within a particular context. Finally, they devise and implement strategies to keep the pest population below level at which growing the crops becomes uneconom- ic-known as the ‘economic threshold level’ (ETL).

Among the many positive aspects of this combination of strategies is that it effectively prolongs the useful life of a pes- ticide by ensuring that insects do not rapidly develop resis- tance to it. Such resistance can develop in two ways.

The first is via ‘selection for resistance’. In any natural population of pests there is normal genetic variation, which includes variation in the genes that deal with pesticide resist- ance. Pesticide use inevitably favours the survival and re- production of individual pests bearing the genes that confer increased resistance.GO

The second mechanism is ‘induced selection’. Even if the insect population has no naturally resistant insects, high doses of a pesticide causing mutations could increase the probability of resistance emerging.

Both of these are known to occur with chemical pesti- cides, and it is likely that insect-resistant transgenic plants such as those producing the Bacillus thuringiensis (Bt) toxin I will have the same effect.

Unlike sprays, however, insect-resistant GM plants maintain constant levels of the Bt toxin over an extended period, regardless of whether the pest population is at eco- nomically damaging levels. The selection pressure with insect- resistant GM crops is therefore likely to be much more intense than with pesticide sprays.

Toxin consumption

In order to slow the emergence of insecticide resist- ance, IPM strategies seek to avoid the use of pesticides alto- gether, unless the pest population reaches the economic threshold level. If this happens, farmers using IPM try to ensure that pesticides are only applied in doses that are appropriate for the severity of pest problem.

By contrast, insect-resistant GM crops aim to eliminate pests by encouraging them to eat high doses of toxins. Researchers, for example, are now reported to be trying to amplify the expression production of the Bt toxins to 25 times more than is needed to kill the relevant pest.

In practice, the number of pests killed depends on the amount of toxin they consume when feeding on the plant tis- sue. So producing the toxin in the right dose, at the right time,

and in the plant tissues where the pest feeds, becomes cru- cial.

Unfortunately, reports indicate that levels of the Bt toxin can vary between different Bt varieties, between different parts of individual plants, and over time.

In particular, key parts of the plants’ flowers, such as the pollen, anthers, pistils and ageing flower petals, tend to have lower concentrations of the toxin than other parts of the plant.

Admittedly these studies have only looked at the vari- ability of Bt production under controlled conditions, rather than in farmers’ fields. But the experience of Indian farmers shows that, in practice, the extent to which Bt cotton resists pests is extremely uneven within a season, as well as across years, hybrids and locations.

Refuges are no solution

Another factor that increases the likelihood that pesti- cide resistance will develop is that a single gene the Bt cry1ac gene has been introduced into all the most widely- used cotton hybrids in India, while the same gene is also being introduced into other crops.

In contrast, rather than relying on one technology or method of pest control, IPM encourages farmers to alternate between chemicals that work in different ways. This so-called ‘mortality- source diversification’ helps prevent pests from developing resistance as quickly as they would if faced with a single toxin.

Advocates of Bt cotton and government officials responsible for regulating its use – argue that resistance can be slowed by planting ‘refuges’ of non-Bt cotton, on the basis that this will encourage the survival of insects that are sus- ceptible to the Bt toxin.

In India, however, it is difficult to impose this require- ment, given the small size of many farmers’ plots. Furthermore such ‘biosafety’ measures are also very difficult to monitor and enforce indeed, there is evidence in India that refuges are not in fact being implemented.

The danger is that the widespread use of Bt varieties and other insect-resistant crops will lead to a rise in the num- ber of resistant pests, which will in turn mean that the envi- ronment is subject to an ever-higher volume of spraying, and more poor farmers are driven to despair.

Non Pesticidal Management a better pest management option

Centre for Sustainable Agriculture (CSA), an independ- ent organisation engaged in agriculture research and exten- sion initiated its work in Wardha district in 2006. The work started from the historic ‘Dorli’ village which went on protest and put their village for sale in December, 2005. The vil- lagers were taken on a exposer visit to villages in Andhra Pradesh where CSA in partnership with local farmer groups established Non Pesticidal Management (NPM) and organic farming. The farmers came together and started learning and practicing the alternative approaches to farming along with several other villages.

NPM is an agro-ecological approach which takes into account the local situations and design cropping patterns and production practices based on the local resources. This reduces the costs of cultivation and increases the ecological sustainability.allinist asbla

Pest is not a problem but a symptom. Disturbance in the ecological balance among different components of crop ecosystem (biotic and abiotic) makes certain insects reach

pest status. These problems of increasing pest incidences and pest shifts can be tackled only with better environmen- tal friendly pest management practices. Ecological approaches to pest management should be based on knowl- edge and skill based practices to prevent insects from reach- ing damaging stages and damaging proportions by making best use of local resources, natural processes and communi- ty action’.

  • Understanding crop ecosystem and suitably modifying by adopting suitable cropping systems and crop production practices. The type of pests and their behavior differs with crop ecosystem. Similarly the natural enemies’ com- position also varies with the cropping systems.
  • Understanding insect biology and behavior and adopting suitable preventive measures to reduce the pest num- bers.
  • Building Farmers knowledge and skills in making best use of local resources and natural processes and community action. Natural ecological balance which ensures that pests do not reach a critical number in the field that endangers the yield. Nature can restore such a balance if it is not meddled with too much.

The farmers also have adopted an incremental approach whereby they try the shift on an incremental basis first reduc- ing and giving up pesticides, fertilisers, organising their own seed production program and engage with the mar- ket. Cur- rently, the farmers are organised into a Farmer Producer Com- pany.

  • Working with 1750 people in 35 villages in two districts (Yavatmal and Wardha) of Maharashtra land bes
  • Among them about 724 (41%) are completely pesticide free and about 338 (19%) have become organic and oth- ers are in various stages of shift other are in various stages of shift
  • Pesticide use reduction it was 100% with 1062 farm- ers which includes 338 organic farmers (amounts to Rs. 53.10 lakhs) and about 70% with the rest (about Rs. 0.32 lakhs) during 2012-13
  • Fertiliser use reduction: 338 farmers have reduced their fertiliser use by 100% (amounts to Rs. 7.65, lakhs) and about 40% by the rest (amounts to Rs. 13.53) during 2012- 13
  • Naisargic Sheti Beej producer company is currently into production and marketing of Soybean, Wheat, Bengal Gram, Cotton, Red Gram and vegetable seeds grown in organic conditions.