Scientist at Work Blog: The Problem With Coffee Pests

S. Amanda Caudill, a doctoral student at the University of Rhode Island, writes from Costa Rica, where she is assessing mammal diversity on coffee farms.

Monday, Feb. 6

The coffee berry borer is one of the predominant coffee pests in the region. It can devastate crops by ruining coffee berries and the quality of the coffee. To make matters worse, it is very difficult to control. The two most common insecticides used during outbreaks are endosulfan and chlorpyrifos, both of which are known to be highly toxic to animals, including humans.

In a parallel research effort, Fabrice DeClerck, my adviser at Catie (short for Centro Agron?mico Tropical de Investigaci?n y Ense?anza), and some of his colleagues, Jacques Avelino, Amada Olivas and Cipriano Ribera, previously conducted field studies on the coffee berry borer around the Turrialba area. They found that the dispersal of the coffee berry borer may be blocked by forest patches.

If there are forest patches next to coffee farms, the forests may act as a barrier and reduce coffee berry borer outbreaks without the use of toxic chemicals or large amounts of labor. So part of my research ? in addition to investigating mammal biodiversity ? is to understand if these forest patches next to coffee farms could increase habitat value and provide corridors for mammals.

This ?coffee-forest matrix,? as it?s called, could be a win-win situation, creating a barrier for the coffee pests while protecting forests and wildlife habitat. I am interested to find out if this theory holds true. We will have to wait and see what shakes out after all the data is collected and analyzed.

For our fourth and final round of mammal sampling, we will sample each of the three sites in the same order as the other rounds: the Catie site first, then the site in Jicotea, and lastly the coffee farm in Aquiares. Each site will be sampled for approximately two weeks; we will have a total of 46 sampling nights at the three sites.

This final round of sampling at Catie yielded the highest capture rate yet for this site: 1.45 percent. Capture rate is the number of animal captures divided by the sampling effort ? the number of traps multiplied by sampling nights. For Rounds 1, 2 and 3, the capture rates were 0.78 percent, 0.71 percent and 0.66 percent, respectively. These capture rates include recaptured animals, and for this round at Catie we had quite a few recaptures. There were two male dusky rice rats ? one adult, one juvenile ? that were captured in the forest minigrid (a high-density trap area with 32 traps in a 900-square-meter area) almost every day. Two of my field assistants also saw the younger rat eating a grasshopper and a spider, which were both in the bag with him when he was being weighed. This little rat had quite an appetite!

For this round, more than half of all the captures were in the three minigrids: 34 of the 54 total captures (including recaptures). But we had only seven individuals running around being captured within the minigrid traps on a daily basis.

Also, after two rounds of zero captures, we had six captures in the organic coffee this time. All of them were of the same Oligoryzomys species ? pygmy rice rats ? tiny little mice that weighed an average of 10 grams. We have not seen very many of this species at the Catie site. More than 75 percent of all the captures for this round were dusky rice rats.

In general, we see more snakes at Catie than at our other two sites, but there seemed to be even more snakes here this round. A snake we have to be very vigilant about is the fer-de-lance, which in Spanish is called terciopelo. It is highly poisonous and abundant on farms ? not a good combination.

The weather, however, has been absolutely gorgeous. It is cool and brisk early in the mornings as we head out to the field. There are beautiful orange and yellow flowers in the treetops that stand in contrast to the bright blue skies. It is amazing to be outside hiking around our sites for such a large part of the day. This has been a tremendous effort and although it?s too early to say we are on the homestretch, the finish line is in our sights.

Source: http://feeds.nytimes.com/click.phdo?i=13286780a6e513f90f3834e82a6d1dd1

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