These Bugs Make Manna And Mow Down Weed Trees

THE BIBLE SAYS MANNA FROM heaven fed the Israelites while they were in exile. The insect that produces manna is coming to the rescue again--this time, to save the Western U.S. from an infestation of saltcedar trees.

The manna scale insect, a native of the arid lands around the Mediterranean, produces manna, a liquid that tastes like honeydew. The pea-size insect feeds on the saltcedar tree, which was brought to the West as an ornamental tree around 1837. Without any manna scale insects to suck their sap, saltcedars have become a weed tree in Western streams. They cover 1.5 million acres, especially from West Texas through Arizona, crowding out native trees and providing a poor habitat for birds and mammals.

The U.S. Agricultural Research Service, helped by Israel's Tel Aviv University, plans to release manna scale insect egg sacs along Arizona's Rio Grande and lower Gila River by next spring. Jack DeLoach, a researcher in Grassland, Tex., says the insect feeds only on saltcedar, so it should make an excellent natural herbicide.

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