Dr. Juliana Jaramillo, a researcher working in Kenya at ICIPE, kindly sent me a few papers concerning Coffee Berry Borer (Hypothenemus hampei) and the effect on climate change. For a lot of people reading this, the ins and outs of pest control in coffee producing countries isn’t particularly compelling stuff. That doesn’t mean it is isn’t important, nor deserving of wider attention and interest.
To give a quick idea of its impact: It is estimated to cause losses of over $500 million USD per year, and affects 20 million coffee producing families worldwide. Despite this there seems to be a lack of funding in research to provide solutions.
A quick primer on the beetle
Coffee Berry Borer, also known widely as Broca, is technically a small beetle native to Africa – though its effects are now global. It destroys crops by using the fruit as a home for its young. The female beetle burrows into the fruit and lays eggs inside. These eggs hatch and the larvae eat the coffee seeds from the inside out. By doing this they massively reduce income for coffee producers by reducing yield, as well as quality.
There are a few different ways to control the pest – some to prevent attack, and others to deal with damaged fruit. Pesticides are only useful before the fruit has been infested. I found a few different suggestions for pesticides online, only to later find that they had been banned in some countries for the unsustainable and negative impact on the environment. (Pesticides like endrin)
Probably the most common solution are traps. These are pretty easy to make yourself, though they can be purchased. These work by luring the beetles into the traps (often using pheromones), where they are captured and drown.
CIRAD claims that traps can increase affected yields by 10-16%, and cost less than using insecticides. You still have to use some form of chemicals. There is more information about traps here (pdf), and a guide to making one yourself here.
A control that is considered more sustainable (and acceptable under organic farming certifications) is the introduction of a natural enemy of the beetle.
Enter Karnyothrips flavipes which are a species of thrips, and quite possibly a natural predator of berry boras. Dr Jaramillo’s latest paper1 looks at whether this is a viable predator that could introduced to help suppress the coffee berry borer. Obviously introducing a species into a new environment comes with a whole new set of issues, though it may already be in various countries and simply needs an increase in numbers and concentration.
The thrips follows the borer into the cherry and lays its eggs, and then eats the borers undeveloped young. Obviously it doesn’t prevent initial infestation and damage, but can limit the size of the borer population.
The other organic option was similar – to introduce a parasitoid. A parasitoid is very much the same as a parasite, with the exception that it will ultimately kill the the host. In the past various wasps have been used, with limited success.
Global Climate Change
I don’t think we can really question this is happening. We’re seeing its effects and there is plenty of data to support it. Below is a graph from a paper titled “The impact of climatic variability and climate change on arabic coffee crop in Brazil”, which can be found (in English) here.
The effects have also been studied in Mexico. In a paper titled “Potential Impacts of Climate Change on Agriculture: A Case of Study of Coffee Production in Veracruz, Mexico” (abstract available here) one conclusion is that by 2020 the model projects that the increase in temperature would result in a 34% reduction in crop, meaning that growing coffee would no longer be financially viable there.
I also found this interesting little graphic showing the change in coffee producing area with temperature in Uganda. I know it is concerning robusta but I still think it is relevant.
Added to the fact that climate change is already causing problems for coffee in places like Colombia, specifically with a substantial increase in leaf rust, it is also worrying to read Dr Jaramillo’s paper from 2006 ((. To quote from it:
“In the case of H.hampei, average daily temperatures of 26°C could lead to a reduction of the maximum intrinsic rate of increase, and, consequently, reduced pest activity in coffee plantations. Over the last three decades, the average daily temperature per year ranged between 17.3–22.3°C for Ethiopia, 18.7–24.5°C for Kenya, 22.3–29.8°C for Tanzania and for Colombia 15.5–29.3°C (data from 1989 to 2007, as H. hampei was introduced in 1988 into the country). The potential number of H. hampei generations per year was in average 3.4 for Colombia, 3.1 for Kenya, 3.1 for Tanzania and 1.3 for Ethiopia. According to our predictive model, in regions where the actual average daily temperature has not yet reached 26.7°C, every 1°C increase, would also increase the actual rate towards the maximum value by an average of 8.5%.”
Many coffee growing regions are below the temperature threshold that sees a reduction in broca. Global warming will push many regions into the temperature zones that will see a significant increase in the rate of reproduction – which is obviously a concern.
So we’re looking at an increase in borers in many parts of the world. Not good. I’d be interested to hear from people, especially those with an interest in organic and sustainable growing, about how they feel about introducing predators from outside the specific ecosystem to deal with the problems.
Combine CBB with leaf rust and other issues, and there are certainly some serious challenges for coffee ahead due to the effects of climate change. I’d love to hear more from people who are travelling and dealing with lots of producers on this subject. Tom Owens briefly mentions some issues in this post (which you should all have read!). I also feel like I’ve skimmed this topic slightly – so if people have good links they want to share do please post a comment!
- Juliana Jaramillo & Eric G. Chapman & Fernando E. Vega & James D. Harwood (2010) Molecular diagnosis of a previously unreported predator–prey association in coffee: Karnyothrips flavipes Jones (Thysanoptera: Phlaeothripidae) predation, on the coffee berry borer [↩]