One program is looking to connect fundamental research with improving cabbage yields in Africa, and in so doing contribute to solving a looming pan-African problem.
Cabbages are not indigenous to the continent but have become a major cash crop for Ghanaian farmers and an important source of income for traders to markets and hotels.
"A good crop can bring in money to buy fertilisers and farm equipment, and also help to pay for healthcare and education for the family," insect expert at the University of Ghana, Dr Ken Fening says. Recently, however, fields of stunted, yellowing, wilting cabbages, their leaves curled and dotted with mould, have become an all too familiar and devastating sight for the farmers of Ghana.
"It seemed to be associated with massive infestations of pink and green aphids," says Fening, "and from my studies of the way insects interact with many different vegetables, I'm familiar with the types of damage they can cause."
With funding through the CAPREx programme, Fening began work with Cambridge plant biologist Dr John Carr. The pair collected samples of cabbage plants in Ghana showing signs of disease, and also aphids on the diseased plants. Back in Cambridge, Fening used screening techniques including a type of DNA 'fingerprinting' to identify the aphid species, and sophisticated molecular biology methods to try to identify the offending virus.
"We found that two different species of aphids, pink and green, were generally found on the diseased cabbages," says Fening. "It turned out this was the first record of the green aphid species, Lipaphis erysimi (Kaltenbach), ever being seen in Ghana." The pink aphid was identified as Myzus persicae (Sulzer).
What's more, the virus was not what Carr expected, and work is now ongoing to identify the culprit. The sooner it can be characterised, the sooner sustainable crop protection strategies can be developed to prevent further spread of the disease, not only in Ghana, but also to other countries in the region.
