1. The sugar beet and virus disease

Each year, about 20%-25% of the area cultivated with sugar beet in Germany is affected by the virus disease rhizomania that has spread from Italy throughout the whole of Europe since the 1950s.
In infested areas, this beet disease causes major economic damage: once it has spread in a given region, the virus cannot be eradicated, and crop losses of as much as 50% ensue. Sugar content - an essential quality parameter in sugar beets - lies between 16% and 18% in healthy plants. Infected sugar beets frequently display a sugar content lower than 10%.
The causative agent of the beet disease is beet necrotic yellow vein virus (BNYVV), for which the soil fungus Polymyxa betae acts as a vehicle. In soil the spores of this virus can remain active over long periods of time In the advanced stage of the disease the infected leaves form lateral roots which then turn brown. This dense root proliferation of the beet has given the disease its name of "root-beard" in Germany. Another symptom is the stunted growth of the underground storage organ. Due to this change in its composition, the malformed beet does not lend itself to commercial processing.
It is not possible to combat the virus mediator - the soil fungus Polymyxa betae - by chemical means. Field-cultivation measures such as extending the distances between the beets or the cultivation of crops in between - have not yet been shown to be beneficial.

2. A sugar beet that protects itself against the beet necrotic yellow vein virus

The introduction of virus with only a slight infection potential into a beet population can prevent or at least attenuate the effects of subsequent infection with related, more aggressive virus, because the plant has already started to form a defence mechanism against the virus in question. This phenomenon is based on the presence of viral-sheath protein material in afflicted plant cells. It is called "premunition".
A laboratory method has been developed by which it is possible to isolate the gene that carries the information for the production of the viral-sheath protein from the genetic material of the virus. The gene has been stabily incorporated into the genetic material of the sugar-beet plant, which goes on to produce the viral-sheath protein in all its cells, in minute quantities. The presence of the viral-sheath protein provides the plant with protection against the virus disease.
After rigorous development in the laboratory, the climatic chamber, and under greenhouse conditions, genetically modified sugar beets went on to be tested under field conditions at several locations in Europe. Up to April 1999, 251 approved or applied releases had been registered regarding genetically modified sugar beets in the European Union; of this total, 51 involved the virus-resistance property.
The evaluation of the initial field-study data shows that the genetically modified sugar beets indeed possess a resistance towards the virus. (Büchting, 1995). The resistant sugar beets show no difference in terms of their external appearance and other characteristics when compared with conventionally cultivated plants. Their susceptibility towards other viruses and other pathogens was not diminished by the genetic modification.
Sugar from genetically modified sugar beet is chemically identical to conventional sugar. Consequently, foods manufactured using sugar from genetically modified sugar beets do not differ from products made with conventional sugar.

3. Herbicide-tolerant sugar beets for better weed containment

Besides the virus disease rhizomania, the problem of weed containment is a major problem in connection with sugar-beet cultivation. In comparison with other crops, the sugar beet is not capable of holding its own very well in competition with weeds, and weed-containment measures must be continuously conducted. A major proportion of genetically modified sugar beet that has been released in Europe are therefore characterized by herbicide-tolerance. Up to April 1999, 227 applications for the release of herbicide-tolerant sugar beet had been made in the European Union (out of a total of 251 field experiments with transgenic sugar beets). The number of scheduled releases is, however, greater than this figure, since an application generally mentions several locations.
Glyphosate (Roundup) and glufosinate (Liberty) are effective against all types of plants, which is why they are termed "broad-spectrum herbicides"
The herbicide Roundup has been in use for 25 years now, while the herbicide Liberty has been on the market under the "Basta" trademark since 1984. These herbicides are used in more than 100 countries worldwide.
The selective pressure resulting from the use of glyphosate and glufosinate has not resulted in the emergence of any new types of weeds resistant towards these herbicides.
Toxicological investigations have shown that glyphosate and glufosinate are harmless for humans and animals (Malik et al., 1989). The acute oral toxicity (immediate toxicity when taken orally) is roughly in the same region as that of table salt. Studies into the chronic toxicity made over a period of two years have not revealed any damaging effect. The substance's mutagenicity and teratogenicity (damaging effect on the genetic substance and on unborn life, respectively) have also been investigated without yielding any evidence of detrimental effects in this regard.
The active constituents glyphosate and glufosinate that genetic-engineering methods have now made viable selective herbicides are ecologically well tolerated. This is due to the fact that the active constituents are rapidly degraded in the soil (within seven to 20 days). What is more, the degradation products themselves, namely water, phosphate, and carbon dioxide, are non-toxic.