A South African tissue culture lab has procured the exclusive rights to distribute a banana variety that offers moderate resistance against banana wilt, a soil-borne fungus that has wreaked havoc on bananas in southeast and South Asia, the Middle East and parts of Africa.
Du Roi Laboratory, which is a local banana tissue culture lab, has been given exclusive commercialisation rights to Formosana, a variety of banana that offers moderate resistance against the disease.
The agreement, made with the Taiwan Banana Research Institute (TBRI), now allows Du Roi Laboratory to exclusively supply Formosana banana plants to the Middle East, Africa (including South Africa), the Caribbean Islands the French West Indies and both South and Central America.
Banana Fasurium wilt, also known as banana wilt, is considered one of the most destructive diseases to befall bananas.
According to Professor Altus Viljoen, chairperson of Fasurium Research at Stellenbosch University’s department of plant pathology, Banana Fusarium wilt is a fungal disease caused by Fusarium oxysporum f. sp. cubense (For).
“The fungus is soil-borne, and spreads to new fields with infected planting material with soil attached to shoes, equipment, machinery, and with water. The disease can be very damaging to susceptible banana varieties and can kill up to 100% of plants in severely infested fields,” he says.
Fungus hampers banana production
The fungus infects banana plants through the roots, and then colonises the remainder of the plant to cause a lethal wilt. When moved in infected plants, symptoms can develop within three months.
“When clean plants are planted in Foc-infested fields, the disease can develop within six months. After infection, the fungus multiplies inside plants, blocking the vascular tissue to prevent water transport, and in this way causes wilting and death of plants. Once dead, millions of fungal spores are again deposited back into the soil which makes further banana production in such fields difficult,” Viljoen says.
Speaking to Food For Mzansi, Suné Wiltshire, general manager of Du Roi, says the lab learned about Formosana during the 2016 annual Acorbat International Symposium. Here, they decided to make contact with the TBRI to form a relationship.
“Foc has never been eradicated from infested banana fields before, as it produces hardy spores that can survive in soil for decades.”
“Later that year we met them in the plantations of Matanuska, Mozambique, where Formosana was planted in response to the presence of Foc TR4 (Foc Tropical Race 4). After seeing the performance of Formosana in the field, Du Roi Laboratory started the discussion with TBRI in becoming the preferred commercial supplier of Formosana,” she says.
Wiltshire clarifies that Formosana is not a genetically-modified banana type, but is rather selected through a soma clonal variation process. This means that it is a genetic variation that is present in plants regenerated from tissue cultures.
“Any grower interested in planting Formosana in South Africa will be able to do so. Du Roi Laboratory has several Formosana trial sites to further evaluate the variety and to identify possible improved selections from the variety,” she adds.
According to Viljoen, only Foc Subtropical Race 4 is present in South Africa and is found in the Hazyview area and southern KwaZulu-Natal.
“It is important to know that neither Foc TR4 nor Foc Race 1 have been reported in South Africa,” he says.
“Foc has never been eradicated from infested banana fields before, as it produces hardy spores that can survive in soil for decades. Some treatments may reduce spore load in the soil, but it cannot eradicate it. The fact that it lives in the soil makes it hard to target with chemicals.”
He warns banana farmers that there are only two options to deal with the disease: preventing it from being introduced to the farm entirely, or replacing susceptible bananas with resistant ones.
“It is extremely difficult to survive the disease by growing susceptible varieties once Foc is established in banana fields,” he concludes.