08-28-2009, 05:28 AM
http://www.fs.fed.us/psw/programs/ipif/s...l#anchor.2
Proposed Strawberry Guava Biocontrol Plan
In 2005--following 15 years of research in Hawaii and Brazil--researchers with the Institute of Pacific Islands Forestry submitted a proposal to release a scale insect in Hawaii to control the growth and spread of strawberry guava.
The insect, a Brazilian scale (Tectococcus ovatus), was selected as a candidate after many years of research showed that it could safely and effectively control the invasive tree in Hawaii without posing a threat to other plant species. Studies demonstrated that the scale is adapted to feed only on strawberry guava, ultimately causing reduced growth and seed production.
The Brazilian scale is a member of a group of insects known as "gall formers." Their young settle and feed on newly sprouted strawberry guava leaves and cause them to form growths, known as "galls." Because the plant expends energy on forming the galls, fewer resources are available for producing new stems and fruit. As a natural predator of strawberry guava, the Brazilian scale can slow the tree's growth and spread, making it less competitive against native plants. The scale is not capable of killing strawberry guava trees, only acting as a check on their growth and spread.
The young scale insects can move about by crawling or by floating with wind currents and, if released, would gradually spread over a period of decades. At the points of introduction of the scale, reduced strawberry guava growth and seed production should be noticeable within a few years. Because scale insects are entirely dependent on their plant hosts, if strawberry guava populations were to gradually decline, so, too, would the scale population.
Proposed Strawberry Guava Biocontrol Plan
In 2005--following 15 years of research in Hawaii and Brazil--researchers with the Institute of Pacific Islands Forestry submitted a proposal to release a scale insect in Hawaii to control the growth and spread of strawberry guava.
The insect, a Brazilian scale (Tectococcus ovatus), was selected as a candidate after many years of research showed that it could safely and effectively control the invasive tree in Hawaii without posing a threat to other plant species. Studies demonstrated that the scale is adapted to feed only on strawberry guava, ultimately causing reduced growth and seed production.
The Brazilian scale is a member of a group of insects known as "gall formers." Their young settle and feed on newly sprouted strawberry guava leaves and cause them to form growths, known as "galls." Because the plant expends energy on forming the galls, fewer resources are available for producing new stems and fruit. As a natural predator of strawberry guava, the Brazilian scale can slow the tree's growth and spread, making it less competitive against native plants. The scale is not capable of killing strawberry guava trees, only acting as a check on their growth and spread.
The young scale insects can move about by crawling or by floating with wind currents and, if released, would gradually spread over a period of decades. At the points of introduction of the scale, reduced strawberry guava growth and seed production should be noticeable within a few years. Because scale insects are entirely dependent on their plant hosts, if strawberry guava populations were to gradually decline, so, too, would the scale population.