While the potato industry has known about black dot for a very long time, it’s always been an afterthought on the disease list, far behind PVY, verticillium and the early die complex, various rots and others.
Producers tend to assume its cost is, at least compared to other diseases, relatively low. However, we are realizing it’s costing producers real yield and real money.
As we keep learning more about diseases and disease complexes, it’s more and more clear that black dot is a significant yield robber that deserves closer attention. Recent research shows that black dot, caused by the fungus Colletotrichum coccodes, can be part of the early die complex, working synergistically with Verticillium dahliae and root-lesion nematodes to weaken plants and reduce yields.
Black dot preys on plants already compromised by other stress factors, whether that’s moisture challenges, nutrient deficiency, or prior infection. It thrives in weakened plants. Once established, black dot is difficult to control, spreading through soil and plant debris and persisting in fields for years.
Is black dot’s incidence increasing? That’s hard to say as it’s been overlooked for so long. One thing is certain: the pathogen is prevalent. As farmers increasingly realize, black dot is costing marketable yield in many fields.
The financial impact is hard to pin down especially in North America, where black dot often co-occurs with verticillium, making it difficult to separate their individual effects. However, trials in South Africa where black dot occurred in isolation showed dramatic yield losses, with production dropping by more than 50% in infected fields in some cases. When growers introduced Strike soil fumigant to suppress black dot, yields rebounded to pre-infection levels, nearly doubling in affected fields.
As the true cost of black dot becomes increasingly evident, the need for effective, targeted management tools has never been greater. Strike, a modern soil fumigant that uses the active ingredient chloropicrin, offers a highly selective approach to managing this persistent pathogen. By targeting black dot’s fungal sclerotia in the soil, Strike interrupts the pathogen’s lifecycle while actively supporting the soil’s microbiome.
Fields treated with Strike have consistently shown impressive results. Growers report not only higher yields but also stronger, more resilient plants that can better handle environmental stresses. In one striking example, trials in Argentina demonstrated a remarkable yield increase – in fact, more than doubled – in just one season thanks to Strike.
Strike’s selective action makes it an excellent fit for integrated disease management strategies. Combined with practices like crop rotation, soil health improvements, and careful monitoring, it provides growers with a powerful tool to minimize black dot’s impact and unlock their fields’ full potential.
