![]() Trees of many ages and sizes have died from this disease. Symptoms Crown, branch, and entire tree dieback with clumps of shrunken leaves in the canopy and heavy seed crops. elongata appears to be causing similar damage in bigleaf maples with water stress playing an important role in exacerbating the damage. The saliva of the potato leafhopper mechanically injures host plant cells that transport water and nutrients, causing "hopperburn." E. This is a native leafhopper on bigleaf maple and is a relative of the potato leafhopper, Empoasca fabae, which causes a great deal of damage to field crops in the Eastern US. Leafhoppers may be heavily involved with Empoasca elongate as the primary insect. These abiotic factors, such as drought, are possible but none has emerged as the definitive cause. The decline was positively associated with sites closer to roads and with increased development, and with increases in summer temperatures. Testing for the bacterium Xylella fastidiosa has been negative. Many pathogens have been ruled out as the primary cause (but may be involved in secondary symptoms) including Armillaria, various oomycetes, Nectria cankers, stem decay fungi such as Ganoderma, and Verticillium. The problem is widespread throughout western Washington and Oregon and may extend into California. ![]() Forest pathologists have been investigating a new decline and dieback of bigleaf maple that emerged in 2010. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |