Opponents of the planned introduction of a biocontrol agent for strawberry guava have raised several arguments. Here are the top concerns, along with the responses from scientists with the Forest Service, the USDA Agricultural Research Service, and others:
• The insect will attack common guava. No, says Tracy Johnson, the Forest Service entomologist. Johnson has attempted to get the scale insect Tectococcus ovatus to infest more than a 80 other plants in 25 families, including common guava (in the same genus as strawberry guava), native Hawaiian plants in the Myrtle family, and even more distantly related plant species. The insect refused them all. Apart from strawberry guava, the only plant that it did colonize was Psidium spathulatum, a closely related species from Brazil that is not found in Hawai`i.
• Hunters and gatherers will have no more fruit. Infested trees will continue to fruit, but at a reduced rate, the scientists say.
• People who use strawberry guava wood for smoking meat will be inconvenienced. Not likely. Thousands of acres of waiawi thickets will continue to provide meat smokers with ample supplies for generations to come.
• Past biocontrol efforts, such as the mongoose, have been disasters. The mongoose was introduced to Hawai`i more than a century ago, with no environmental review or scientific study done before the sugar planters brought it in. Since the 1970s, no biocontrol agent released in Hawai`i has damaged non-target plants.
• The economic value of products made with waiawi will be damaged. At the Hilo information meeting, a $3.99 fish scaler, made of two bottle caps bolted to one end of a foot-long stick of waiawi wood, was held out as an example of the economic value of the plant. But stands of waiawi will continue to exist for decades to come, more than enough to saturate world markets for fish scalers.
• Large stands of dead waiawi could fuel terrible fires. Again, not a likely scenario. The biocontrol insect does not kill the plant: Tracy Johnson said in all his testing, even on small plants, none had died after being infested with T. ovatus. “This is not a tree killer,” he said at the June informational meeting. “Waiawi will persist a very long time with the insect… It just suppresses growth.”
— Patricia Tummons
Volume 19, Number 1 July 2008
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