Failing GM maize
I refer to Monsanto Agent Hans Lombard’s letter (4 July). The SA advertising authority has on two occasions ordered Monsanto to remove adverts making claims such as those made by Lombard in his letter. T he African stalkborer Busseola fusca is indigenous to and feeds on all grasses including indigenous sorghum and non-indigenous maize. First generation moths appear in spring and produce roughly 1 000 eggs laid at various sites in batches of about 150. The eggs take nine days to hatch.
Second generation moths emerge from late January and the cycle is repeated. hatched larvae are most vulnerable shortly after hatching when crawling up the outside of the plant. On maize the first generation larvae take about 30 days to mature, feeding on the rolled up leaves until strong enough to bore into the stem and pupate. Second generation larvae crawl up the stem and attack the cob. Once mature they bore into the stem, where they hibernate over winter. In this state they are again extremely vulnerable. With the approach of spring the larvae pupate. he most effective control is to remove the stover and feed it to cattle. Root stubble should be deep ploughed because emerging moths can’t get through the soil. Bacillus thuringiensis kurstaki (Berliner) (Bt) is a naturally occurring bacteria in Africa which attacks hibernating larvae. beyond doubt that naturally occurring Bt plays a significant role in the environmental cycle. Dr Kfir of the ARC confirms this at http://www.arc.agric.za/Pages/Home.aspx.
Commercial formulations, both granular and liquid, applied by conventional methods or through pivot irrigation, and almost non-toxic to other beneficial organisms, are extremely effective at the hatching, crawling and early eating stages of the larvae. For this reason they’re used by organic farmers. The creation of Bt-resistant stalkborer has effectively neutralised this economically important means of control. G M Bt maize contains a synthetic Bt gene unknown in nature which constantly exudes Bt toxin. Bearing in mind Bt plays a significant role in the cycle of reducing stalkborer in natural vegetation, would say this is an environmental disaster. It’s no good blaming farmers for not planting a refuge of 5% non-GM maize. rap crops around the border encourage spring moths to lay their eggs before the main crop is up.
This can be used to make silage or fed directly to cattle before the second generation pupae are formed. Pheromone traps which attract mating moths are another helpful method. he recommends farmers choose cultivars that can withstand chemical spraying. Farmers would be foolish to pay a premium for a failed GM product and then still have to pay for chemicals. Having now created Bt resistant stalkborer, Lombard tells us, Monsanto’s answer is to starve stalkborer should it become a problem in future. Anyone who believes that must be suffering the consequences of eating too much GM. would like to thank Lombard for pointing out that as early as 2003 Monsanto was aware of the 90-day rat study which proved rats fed Monsanto NK603 GM maize suffered reduced liver, heart and brain size. He makes the point that this maize has been available since 2002 as a staple diet in SA and Monsanto did nothing to notify unsuspecting South Africans of this important study. Trevor Wells, Muizenberg