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…..as 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.)
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| 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.
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| 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.
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| 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!
