The banana is under serious threat. A fungus, Fusarium oxysporum cubense Tropical Race 4 (TR-4) can potentially wipe out the banana as we know it in a few short years.
Scientists are working around the clock to save one of the world’s most important foodstuffs. Most of these scientist are trying to create a resistant type of banana via the genetic route. Because the current banana, the Cavendish, does only contains seeds on extremely rare occasions, it cannot begrown in the usual way. But this all takes time, and time is a currency we do not have.
So, maybe we need to look for other temporary solutions to safeguard our banana. Chinese research indicates that Chinese leek (Allium tuberosum) has an inhibitory effect on the fungus that creates Fusarium wilt and may be an efficient way to control the disease until science has created a new variety of banana that is resistent to Fusarium oxysporum TR-4.
Adopting a rotation system with Chinese leek and banana, reduced the Fusarium wilt incidence and disease severity index by as much as 88%-97% and 91%-96%, respectively, and improved the crop value by 36%-86%, in an area heavily infested by Fusarium oxysporum TR-4 between 2007 and 2009.
Crude extracts of Chinese leek completely inhibited the growth of Fusarium oxysporum on Petri dishes, suppressed the proliferation of the spores by 91% and caused 87% spore mortality.
The findings of this study suggest that Chinese leek has the potential to inhibit Fusarium oxysporum growth and Fusarium wilt incidence. This potential may be developed into an environmentally friendly treatment to control Fusarium wilt of banana.
 Huang et al: Control of Fusarium wilt in banana with Chinese leek in European Journal of Plant Pathology - 2012