India wary as SA GMOs trigger pest resistance

India’s official reasons for more research and tests are welcomed. The official Indian government statement of the ministry of environmental affairs and forests takes into account serious concerns from the international community surrounding the build up of resistance to the beneficial Bacillus thurengiensis.

Dr Jack Heinemann of the University of Canterbury, New Zealand pointed out that the Bt Brinjal tests conducted in India would not meet careful international standards.

Resistance management strategies are essentially developed based on output profiles of stochastic models which integrate toxicological, ecological, genetic and biological parameters. Stochastic models for resistance should be developed to calculate resistance risk and devise pro-active insect resistance management (IRM) strategies.

The structured refuge strategy of 5 per cent conventional Brinjal within the ecosystems of Bt Brinjal proposed by Monsanto is based on basic simplistic assumptions and not through defined algorithms and modelling and was unceremoniously rejected.

Mathaba News has previously reported on the serious ecological malfunction caused by the introduction of GM crops in Africa.

The African experience, recorded below, is pertinent.

The African stalkborer (Busseola fusca), known as the stalkborer, has lived in Africa for thousands of years. It bores into the stalks of all indigenous grasses and thus plays a vital role in the natural ecology of Africa.

The Bacillus thuringienis (Bt) is a bacteria which has existed throughout the world for thousands of years. It plays a vital role in the balance of the ecology of all grasses throughout the world by attacking, inter alia, the vulnerable diapause larvae of insects hibernating in the dormant dry stalks of all grasses throughout the world. (Diapause is a period of suspended development or growth occurring in many insects and other invertebrates during which metabolism is greatly decreased.)

‘This important bacteria (Bt) secretes a crystal pesticide (Cry Toxin) which is toxic to the diapause larvae whilst they are in this vulnerable diapause state. For thousands of years the perfect balance between grasses, diapause larvae and Bt has existed… For thousands of years no insect resistance to naturally occurring Bt has ever developed.’

Dr Rami Kfir of the South African Agricultural Research Council (ARC): Journal of African Zoology 107:543-553, prior to the introduction of GM crops, confirmed the high winter mortality rate of larvae of the stalkborer which he attributed partially to Bt which he had significantly isolated, among other pathogens, on the cadavers of diapause stalkborer in the stover (stalks) of maize.

NATURAL BT SPRAY

Decades prior to the introduction of genetically modified (GM) crops, microbial preparations of the entomopatho-genic bacterium Bacilllus thuringiensis (Bt) containing the Cry Toxin were commercially formulated. This had numerous applications in the control of insects, but it’s most significant use for the purposes of this discussion was that it was extremely efficient as a spray in the control of stalkborer throughout the world.

This toxin was particularly popular with irrigation farmers who simply used their overhead sprays to strategically target vulnerable hatching and infantile crawling larvae. A most important, economic factor is that natural Bt spray is used by organic farmers because it is natural and also biodegradable in water, so no residue remains on the produce.

Because insects in some areas have become extremely resistant to synthetic insecticides, particularly the pyrethroids, Bt spray has replaced synthetic pesticide in many areas. It therefore has significant agricultural and economic importance.

After twenty years of use, no stalkborer resistance to natural Bt spray has developed in any field population of maize throughout the world. (Tabashnik 1994).

The first genetically modified (GM) Bt maize containing an edible Cry Toxin was planted in South Africa 1994, and it took only four years for the first resistant African Stalk borer to appear in a number of localities. The first reported cases arrived at the Agricultural Research Centre ARC in Potchefstroom during the 1998/1999 growing season. Professor Van Rensburg attributed this to larvae feeding on the silks which, when mature, penetrated the stalks and went into diapause later to mature into the first seasonal flight of moths.

Bearing in mind that there are two flights of moths each growing season, each moth producing some 1,500 eggs, it is not surprising that during the 2004/2005 growing season, an alarming number reports of severe damage to GM maize crops flooded in to the ARC. What was even more alarming was that they originated from many widely dispersed locations throughout the country. It was not only restricted to Monsanto’s GM maize, but to all brands of GM maize. The one thing in common was that the wide spread reports of severe damage were widely spread throughout South Africa and all involved irrigation schemes.

The fact that the stalkborer has a propensity for developing a resistance to the ever present edible Cry Toxin in Bt maize and the stalkborer’s virile reproductive capacity, has effectively neutralised commercial Bt sprays with severe economic implications to agriculture.

The biggest and probably the most unexpected ecological malfunction was that the natural control reported by Dr Ramy Kfir in the preferred hosts, indigenous grasses, has been compromised beyond repair.

BROUGHT TO YOU BY PAMBAZUKA NEWS

* This article first appeared on Mathaba.net.
* Trevor Wells coordinates the Farmer’s Legal Action Group – South Africa.
* Please send comments to [email protected] or comment online at Pambazuka News.