How much is a pheromone worth?

Pheromone-baited traps have been widely used in integrated pest management programs, but their economic value for growers has never been reported.  We analyzed the economic benefits of long-term use of traps baited with the citrus fruit borer Gymnandrosoma aurantianum sex pheromone in Central-Southern Brazil. Our analysis show that from 2001 to 2013 citrus growers avoided accumulated pest losses of 132.7 million to 1.32 billion USD in gross revenues, considering potential crop losses in the range of 5 to 50%. The area analyzed, 56,600 to 79,100 hectares of citrus (20.4 to 29.4 million trees), corresponds to 9.7 to 13.5% of the total area planted with citrus in the state of São Paulo. The data show a benefit-to-cost ratio of US$2,655 to US$ 26,548 per dollar spent on research with estimated yield loss prevented in the range of 5-50%, respectively. This study demonstrates that, in addition to the priceless benefits for the environment, sex pheromones are invaluable tools for growers as their use for monitoring populations allows rational and reduced use of insecticides, a win-win situation

Influence of Azteca alfari Ants on the Exploitation of Cecropia Trees by a Leaf-Cutting Ant

The foraging activity of the leaf-cutting ant Atta laevigata in an early successional area near Manaus, Brazil, was monitored over a period of 18 mo. Four Cecropia species were growing in that area and all were associated with the ant Azteca alfari. Unoccupied trees (those in which there was no ant response to mechanical disturbance of the stem) were attacked by leaf-cutting ants more often than were trees occupied by A. alfari colonies. Cecropia ulei was the most frequently attacked species. However, leaves of C. ulei were the least preferred ones during assays in which detached leaves of the four Cecropia species were placed alongside the foraging trails of leaf-cutting ant colonies. C. ulei had the largest number of unoccupied trees compared to the other species. In addition, A. alfari colonies associated with C. ulei were smaller than those associated with C. distachya. These data suggest that A, alfari was influencing the selection of Cecropia species by A. laevigata, which harvested more from species that were less defended by the ants (with a higher proportion of unoccupied trees or trees hosting smaller ant colonies), although these were less preferred