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Plague

Hydrogel with pest-fighting worm

A mixture of water, hydrogel and a microscopic worm called Deladenus siricidicola has been simplifying the biological control of Sirex noctilio – a wood wasp accidentally introduced into Brazil and that has become a major pest of pine plantations, according to experiments conducted at Embrapa Forests, in the state of Paraná.  The worm is currently mixed into a gelatin and then applied to trees, where it infects and sterilizes females of the wasp (Agência Embrapa, July 21, 2015).  When it bores into the trunk of a tree, the wood wasp can simultaneously lay up to 500 eggs and secrete a toxic mucus containing spores of a fungus that obstructs the tree’s sap-carrying vessels.  According to the researchers, using hydrogel could be simpler than using gelatin, which takes time to prepare and requires an electric mixer, not to mention both hot and ice-cold water. Hydrogel, water and Deladenus siricidicola can be mixed together in a plastic bag and used immediately or stored in a refrigerator.  The combined action of the mucus and fungus ultimately kills the tree.  The researchers say that this new type of application was able to cut production costs by 46.5% and shorten the time necessary to prepare the pest-fighting solution by 66.7%.  In the states of Paraná and Santa Catarina, pine plantations cover a total area of 145,000 hectares.  The tree is used as raw material in the manufacture of paper, cellulose, wood laminates, lumber products, furniture and resins.  Since March 2015, Embrapa has been using the hydrogel on a 6,276-hectare area.

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