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Torch Farmers Network

The Ominous Green Coffee Scale

Coccus Viridis -Green Coffee Scale Disease

Coccus Viridis -Green Coffee Scale Disease

Green Coffee Scale (Coccus viridis) is the triple-threat of coffee diseases. Scales suck the plant sap and excretes a sweet (honeydew) like substance. Then sooty mould (a black, loose, sooty-like cover) often develops all over the trees because it can feed on the sweet excretion. 

There are a number of natural predators of Green Coffee Scale such as wasps, ladybugs and Verticillium fungus. However, the sweet excretion attracts ants that keep these natural predators away. Therefore Green Coffee Scale doesn’t just give farmers the inconvenience of their presence but they bring mold and ants with them.  Farmers are quickly bombarded with all these symptoms as well as a yellow and bare tree.  

Farmers then have to decide how to solve these problems all at once which could be daunting and confusing.  If a farmer can realize that the Scale may cause all of these symptoms but it is the ants who keep the natural predators of the Scale away, then they can simply and successfully treat the ant-problem and watch the Green Coffee Scale’s natural predators come and take care of the problem for them. If they do not realize the complexity of the situation, they could end up spending more time and money on remedies that don’t work as good.

Additionally, keeping added expenses down will ensure that the farmer is profitable, sustainable and able to expand.  There are two cost effective ways in which farmers can control this coffee plant disease. The first is that it can be controlled with chemicals at quickly and at ease, however the farmer will not only spend money from their already very tight budget, but he/she will also kill off any other insects that are natural predators to the Green Coffee Scale as well as predators of other vulnerabilities to the coffee tree such as the Mealy bugs. 

The second cost effective way is to control the ants with sticky glue around the trunk of the tree which is available in many countries but under different names like diatomaceous earth and lime wash, amongst many other traditional remedies which might already be used locally.

The Arabica coffee manual for Lao-PDR recommends a natural method of tobacco spray to kill Green Coffee Scale.  I have also personally very successfully used the remaining leaves of the soaked tobacco around fruit trees to keep ants away. 

Here's their recipe:  1 kg strong tobacco per 2 L water. Soak for 2 nights. Then remove tobacco. Add 500g of washing powder and make up to 20L. Spray weekly until scales disappear.* 

*Arabica coffee manual for Lao-PDR 

Authors :Edward Winston, Jacques Op de Laak , Tony Marsh, Herbert Lempke and Keith Chapman 


Are you informed as to what it takes for a coffee farmer to be sustainable?

Sustainability is a “hot” word right now.  It is used in many different contexts, from development work in the third world all the way to marketing plans for companies who are trying to reach a conscious and informed market.  Have you ever wondered what the phrase “to be sustainable” actually means?  One of the three definitions that the Merriam Webster dictionary gives for sustainable is the ability "to last or continue for a long time”. When we use that word in the context of coffee, essentially we are asking -"does the coffee farm make a profit?"  If the answer is yes, then the farm can remain on the same level or improve but if we answer no, then the farm will not be able to carry on. They would eventually have to stop growing coffee in order to survive.  Coffee farmers grow coffee to feed themselves and their children, to provide medical care for them and provide an education for their children.  Whilst many coffee farmers love coffee, it is not a choice of convenience or taste but rather of survival.

So what actually enables a coffee farm to make a profit and be sustainable?  

The simple equation is...

The price the farmer receives for their beans/cherries minus all the time, energy and capital they spend growing and harvesting the coffee = their profit. 

But then you need to answer the following equation...

Is the profit the needs of the farmer and their family over the period of time in which they took to produce the coffee.  

What makes coffee and other perennial crops (a plant having a life cycle that is more than two years long) unique is they can easily grow it without maintenance and it can continue to be harvested even if the plant or crop is not achieving a healthy and optimum harvest.  In other words, coffee can be grown with very little expense but will produce a fraction of its potential quantity and quality.  

What does this for mean sustainability? What can you do?

    1.    As a farmer: The jump in progress needed for a farmer to become sustainable requires farmers make a conscious effort to develop their farming practices and give coffee the same effort that is usually given an annual cash crop such as corn or other vegetables.

    2.    As an influencer: Companies and organizations focused on improving sustainability will need to address the farmers needs for coffee agronomy knowledge and skills.  New machinery and equipment is helpful but may only aid the farmer improve the quality of their coffee until the machinery is broken or needs to be replaced.

As the coffee quality improves, so should the price.  Reward for hard work is a integral part of any development plan.  Regions in the world where development is hindered usually have strong influences preventing reward for hard work. Such as, conflict zones where hard work is destroyed by war or neglect, secluded rural areas where middle men take advantage, the farmers distance to the market, or knowledge of the market.

And if you're not directly connected to the coffee industry, be a storyteller and advocate for farmers by supporting other coffee companies that sustainably source.

  3.    As a consumer of coffee: It starts by being informed, but the bottom line is you have to be willing to pay a little bit more money for your cup of joe.  Do it as a thank you, to help those that keep you going and add joy to your day.