Villain Insect Enlisted for Good Deeds
By Ben Hardin
January 19, 2000
Blossoms of sugar apple and atemoya have long attracted pollinating sap
beetles. The problem is, neither these insects nor others seem to have worked
hard enough at their pollination duties. To produce these unusual and tasty
fruits for consumers, commercial orchardists resort to hand-pollination.
A solution: Give the beetles a whiff of chemical attractants and
yeasty-smelling bread dough.
Agricultural Research Service
scientists at the National Center for
Agricultural Utilization Research, Peoria, Ill., first discovered and
synthesized the attractants, called pheromones, that worked well in experiments
to monitor and control sap beetles in crops where they are pests.
Then, to coax sap beetles to better perform their good guy
pollination role, University of Florida and
ARS scientists loaded pheromones and bread dough into bait stations in
flowering sugar apple and atemoya trees. Stymied by screens keeping them out of
the stations, the beetles moved on to pollinate blossoms.
Atemoya and sugar apple, tropical relatives of the Midwestern native paw
paw, are noted for their delicate mango- and vanilla-like flavor and
custard-like pulp. The fruits are often eaten from the shell, cut
into pieces for fruit cups or salads or blended and frozen with citrus juices.
In the two-year study, pheromone bait stations increased by many times the
number of flowers that began to develop and set fruit--a sign of improved
pollination. However, stresses kept many of the extra fruits from developing
fully. Now, improved growing practices that lessen failed fruit development are
helping increase production.
The sap beetlesCarpophilus or nitidulid speciesthat
pollinate the trees also sometimes inflict serious damage on many of the
worlds other minor fruit crops. For example, in some years,
nitidulids have caused $2.5 million in damage to the California fig crop alone.
ARS is the U.S. Department of
Agricultures chief scientific research agency.
Scientific contact: Robert J. Bartelt, ARS
National Center for Agricultural
Utilization Researchh, Peoria, Ill., phone (309)681-6237,