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ROYA IS EVOLVING. SO WHAT NOW?

Coffee plant which lost its leaves due to la roya.  Photo by Kraig Kraft.

World Coffee Research has spoken.  Lempira, a high-yielding, popular variety planted throughout Honduras is no longer what thousands of farmers hoped that it would be: resistant to coffee leaf rust.  While there is not yet any conclusive scientific evidence that la roya has evolved into a new race or strain, all indications are pointing to this – a reminder that we haven’t yet solved this problem.  At present, only Lempira has been implicated in a loss of resistance (resistance means that there is reduced disease on the plant compared to tolerance, which means the plant has the disease/pest, but shows little damage). However, this news should be a very sobering reminder of just how vulnerable farmers are. Honduran farmers have invested four years of limited financial capital and their hard labor to recover from the 2012-2013 rust outbreak, and just as they are currently riding a wave of increased productivity and heightened recognition as a global producer of Arabica coffee, they find themselves looking at repeating this depressing cycle once again.

The answers to this next round of the rust war are not short term answers.  Rather, breeding the next generation of resistant coffee varieties, understanding the genetics and behavior of la roya, and finding ways to help farmers continue to invest in upgrading their farms are the medium term to long term solutions. They require investment of capital and time by talented groups of people working together to create solutions that can be deployed for both large estates and smallholder farmers.

So, what about now?  What about the 2017-2018 harvest in Honduras?  What about the inevitable news that roya has affected another previously resistant variety? How can farmers begin preparing for this? The answers, the tools and technologies available are nothing new, nor should they be a surprise. It’s probably a good time to review what we already know.

Tools for PREVENTION

The best defense is prevention.  The second line is treatment.

How do you prevent coffee leaf rust?  You need limit the spread of the disease – to make it difficult for the disease to find new hosts.  Coffee leaf rust spores are dispersed primarily through the air; limiting spaces where coffee plants are exposed to wind is key.  In this paper (written by Jacques Avelino and some sharp agroecologists at CATIE), they discussed the effects of landscape on the incidence of coffee leaf rust. They found that the incidence of roya was reduced on coffee farms that were located next to plots with trees.  Very simply put, trees block the wind that carry rust spores. A simple, yet effective tool to limit the spread of spores.

Shade is another factor in limiting the disease.  While high levels of shade are considered a negative impact for productivity of coffee, plants that are exposed to direct sun for longer periods of time are stressed plants.  Plants that are heavily stressed do not tolerate la roya and have greater rates of defoliation.

The other disease prevention measure is applying the appropriate amounts of fertilizer (remember the 4Rs – right source, right time, right rate, right place).  Weak, underfed coffee trees fall quickly to la roya, who shows little mercy when presented with a weak host plant.  Healthy coffee plants have the nutrients available needed to produce coffee AND recover.  The foundation to plant health starts at the ground level.  Farms must have healthy, fertile soils to produce health coffee plants.

Tools for TREATMENT

Despite all your best prevention efforts, there is still a good possibility of getting infected. The second line of defense is treatment – which can help limit the damage and most appropriate for small outbreaks.

There are several classes of fungicides that farmers can buy, each with their respective trade-offs (copper based, triazoles, strobilurins) and these are sprayed on infected plants to kill off the fungus.

If fungicide isn’t an option, then quickly cutting away all the diseased plant material is the final choice, in a drastic pruning.  The infected material needs to be removed from the farm.

There are much better technical resources available. World Coffee Research published a fantastic manual on rust control.  CRS and Café Nica documented organic options for management of the coffee farm (and in Spanish).  There are others, I’m sure.

We need more INFORMATION.

This seems like a good time to remind everyone that coffee contributes to approximately $225 billion dollars annually to the economy United States  and this is built on the shoulders of smallholder farmers who are essentially the foot soldiers and infantrymen of our sector. They are on the front lines and engage in all OUR biggest battles first: climate change, diseases, prices and labor shortages.  I’m a card-carrying pacifist, but I believe the war metaphor helps us understand the current situation. In the battle with coffee leaf rust, as with a military conflict, the side that is the best prepared, has the right information, and most resourced is the side that emerges victorious.  I think we owe it to coffee farmers to arm them with the best information intelligence and tools possible before this battle.

Kraig Kraft

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