New strategy required for delaying insect resistance to Bt crops

Kenyan farmer Mary Ngare in her maize field damaged by stem borers © CIMMYT (CC BY-NC-SA)
Kenyan farmer Mary Ngare in her maize field damaged by stem borers © CIMMYT (CC BY-NC-SA)

Transgenic Bt crops have been grown around the world since the 1990s and have contributed to increased yields by controlling agricultural pests. Due to the importance of this technology, there has been continuous study into the development of resistance to Bt crops and how best to avoid this happening. A recent investigation into the rapid spread of Bt resistance in South Africa has revealed one of the more surprising discoveries to date, that the maize stalk borer (Busseola fusca) has evolved Bt maize resistance inherited as a dominant trait for the first time. This has significant impacts on the management of Bt crops, as current methods for sustaining susceptibility rely on the recessive inheritance of Bt resistance.

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Cassava virus resistance breakthrough for Africa

Cassava roots
Cassava is a staple food for millions but is susceptible to viruses that make it unpalatable © Seth Anderson (CC BY SA license)

One of the worst diseases of the tuber crop, cassava, in sub-Saharan Africa is Cassava brown streak disease (CBSD). Since its resurgence in East Africa in recent years, it is now spreading to Central and Western Africa. The other major disease of cassava in this region, Cassava mosaic disease (CMD), can also cause widespread damage to the crop, however there already CMD-resistant varieties of cassava available. Until now, very little natural resistance to CBSD has been found. Plant scientists at the Swiss Federal Institute of Technology (ETH) Zurich have combined natural resistance to CMD with modifications of the cassava genome to develop a variety of cassava resistant to both CBSD and CMD that can be grown in Africa. As cassava is a staple food to millions of people, this new variety has the potential to halt the spread of the disease and prevent famine from crop losses. Continue reading