Several new studies show that pests can spread more quickly if they feed on genetically engineered plants that produce so-called Bt insecticides. According to the studies, the offspring of the surviving insects have a changed wing shape that facilitates longer flights and faster spread. This poses risks for the environment and agriculture.
The pests include butterfly species, e.g. corn earworm (Helicoverpa zea), fall armyworm (Spodoptera frugiperda), beet armyworm (Spodoptera exigua) and western corn rootworm (Diabrotica virgifera virgifera) – the latter being a beetle species. These insects are a significant problem in the cultivation of crops such as corn, soybeans and cotton, amongst others. However, many of the insects in question have developed resistance or are tolerant to the insecticides produced by the genetically engineered plants. In particular, if they have developed resistance or tolerance to the insecticides produced by genetically engineered plants, the altered wing shape allows them to spread more quickly and over greater distances.
The first observations of longer flight distances were published over ten years ago, but at the time the phenomenon was interpreted as a change in the behaviour of the insects. However, recent studies show that they have also undergone a change in wing shape. In addition, there are also indications of higher fitness (increased number of offspring or larger larvae). The latest studies on the cotton earworm showed significantly altered wing shapes in male and female insects after just one generation of larvae feeding on Bt corn.
The long-term and large-scale cultivation of genetically engineered plants is a significant factor in promoting these effects, which is why they are easily overlooked in the context of smaller experimental releases. This risks considerable damage to the environment if, for example, more insecticides have to be used. It can also result in lower crop yields and risks to food security.
The findings from the studies examining the increased spread potential of insect pests are just some of several examples showing that the problems associated with genetically engineered crops often only become apparent after prolonged cultivation. Other examples include the increased fitness of pests, the accelerated spread of herbicide-resistant weeds and problems with genetically engineered papayas trees infected by viruses.
There are good reasons why also plants obtained from new genetic engineering (or new genomic techniques, NGTs) can be affected by similar problems. In these cases, it is not unlikely that new gene variants, which often differ from those obtained through conventional breeding, may lead to a weakening of plant health. This, too, can result in an increased spread of pests and plant diseases. It is particularly problematic in this context that the EU intends to dispense with the risk assessment and traceability of these plants in the future, thus allowing harm to breeding, the environment and agriculture to spread largely unnoticed.
Contact:
Christoph Then, info@testbiotech.org, Tel + 49 151 54638040
Further information
Paper on Spodoptera frugiperda