The disease known as Elm yellows threatens the health of over 200 majestic American elms on the Penn State campus. Elm yellows is just one of many tree diseases that contribute to the decline and death of trees in the United States. What are the main causes of American tree diseases and have we made progress in preventing and treating them?

In Australia, when crossing from one state to another, travelers may encounter a quarantine stop and may be required to forfeit recently purchased fruits and vegetables as a hedge against invasive pests. But in the U.S., crossing state lines is freewheeling, according to researchers from the U.S., Australia and New Zealand, who evaluated the threat of invasive pests to states from within the country.

One of the world's most mysterious insects is about to invade the skies over forest lands in central and eastern Pennsylvania, but an expert in Penn State's College of Agricultural Sciences says it's not a cause for alarm. Residents of Adams, Bedford, Berks, Blair, Centre, Clearfield, Clinton, Cumberland, Franklin, Huntingdon, Lackawanna, Lehigh, Luzerne, Lycoming, Mifflin, Montour, Northumberland, Perry, Potter, Schuylkill, Snyder, Tioga, Union and York counties soon will see an emergence of periodical cicadas, commonly but mistakenly called 17-year locusts.

My brother is easily identified in the field by his characteristic pose: A palm is raised to within a few inches of his face, which is down-turned, studious. The index finger of the other hand is acting as a pointer and a probe. He's picked some tiny thing, some leaf or bug, from a bush or a tuft of grass, and is scrutinizing it.