CO-Horts Blog

Monday, February 12, 2018

Coffee with a little IPM

Posted by: Mary Small
Colorado Master Gardener Program Coordinator
One of the topics I teach in our Colorado Master Gardener program is Integrated Pest Management or IPM. It’s a multi-prong approach to managing pests and can be used in a variety of situations. I wrote about how I used IPM strategies to combat fruit flies in the kitchen last fall. Here’s another story.
Last year at this time, I was in Guatemala on a mission trip. On our free day, a group of us toured a coffee plantation near Antigua, situated at about 5,000 ft in the western highlands.  We were looking forward to the tour and sampling their product at the end.

And then… we wandered down a row of coffee plants, I became distracted when our guide pointed out rust disease on some leaves.  I just had to have a picture! (If you know me, this is no surprise. I like “weird stuff” as my children often have reminded me.)

Rust on coffee leaf
While I was angling for a good shot, the guide told us about the plantations’ disease management strategies.  Their practice was to treat only the plants that had the disease rather than treating the whole crop. Before they treated, they watched the outbreak areas to determine if sprays were really needed. Sometimes they were, sometimes not. In IPM, this is known as “spot treatment”. The purpose of a spot treatment is to minimize pesticide exposure of non target organisms as well as control costs. And this is done by only treating what is necessary – when it is necessary and according to specific threshold levels of the pest.
Trees shading coffee

One of our group asked about the large trees growing among the coffee plants. Why were they there? Didn’t that keep light from reaching the leaves and berries? Well, yes, it did. The light intensity is so high that it “sunburns” the coffee fruit, rendering it useless for the beverage market. The trees are there to decrease the incidence of berry burn. This is an example of a cultural IPM practice – altering the culture (manipulating the environment) to reduce the likelihood of “pest” (read: sun) damage.

Trees with fruit to attract birds
Our guide also pointed out newer trees (whose name escapes me) that were planted with a purpose. One of the plantation’s ongoing problems was birds swooping down into the coffee crop and taking the fruit. (If you raise anything that produces fruit, you can understand the frustration here!) The company tried different strategies until they learned this tree produces fruit that the birds really like. So the tree fruit acts to divert them from the desired coffee crop. Nothing is 100%, but it was more successful than anything else they previously tried. In IPM, we would call this trap cropping. (Think planting radishes to attract the western cabbage flea beetle, so they won’t decimate the broccoli.)
 Now, having raised fruit bearing plants, I’ve since pondered what happens when the birds “re-sow” the seeds of the tree fruit with a little bit of their fertilizer. Didn’t think of it. Too distracted by the wonders of viewing IPM in practice…and fresh-ground Guatemalan coffee!

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