Issue Date: October 31, 2016
New weapons in the fight against fungal wilt
Fusarium wilt, also known as Panama disease, is caused by the pathogenic fungus Fusarium oxysporum and affects many economically vital food crops, including wheat, potatoes, peppers, grapes, strawberries, tomatoes, and soybeans. But the soil fungus poses perhaps the biggest threat to the world’s $5 billion banana industry because of that industry’s near-universal reliance on a single species.
F. oxysporum enters a plant’s root system and multiplies in its vessels, choking off the plant’s supply of water and nutrients. To fight the fungus, farmers rotate their crops, adjust irrigation methods to prevent the fungus’s spores from spreading, and rely on a limited arsenal of chemical fungicides.
But researchers are hunting for better alternatives. A recent analysis by CAS, a division of the American Chemical Society, reveals that patent activity in the area has increased 57% in the past five years. So far, azole-based fungicides continue to dominate the fight. But the war against F. oxysporum is moving beyond small molecules.
The number of patents mentioning F. oxysporum is up 57% since 2010.
Most of those patents involve the azole family of fungicides. Increasingly, crop scientists are looking to wield combinations: For example, BASF claimed mixtures including these two azoles and various biological agents in a 2015 patent (WO 181009).
Number of patents in CAS’s databases—24% of those that mention F. oxysporum--that involve killing the fungus with biological agents or other nonchemical methods. Strategies include treating soils with microorganisms that naturally suppress F. oxysporum and heating them to kill the fungus.
Source: HCAplus on STN, August/September 2016
UPDATE: This story was updated on Oct. 31 to incorporate additional information and correctly characterize azole fungicides.
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