{"id":9273,"date":"2019-12-22T17:24:29","date_gmt":"2019-12-22T22:24:29","guid":{"rendered":"https:\/\/cnr.ncsu.edu\/news\/?p=9273"},"modified":"2024-01-22T21:04:47","modified_gmt":"2024-01-23T02:04:47","slug":"parasitic-wasps-christmas-trees","status":"publish","type":"post","link":"https:\/\/cnr.ncsu.edu\/news\/2019\/12\/parasitic-wasps-christmas-trees\/","title":{"rendered":"Parasitic Wasps Are Making A Meal of North Carolina\u2019s Christmas Trees"},"content":{"rendered":"\n\n\n\n\n

Whether it\u2019s bought at a retail lot or farm, a live Christmas tree is an integral part of the holiday season for millions of Americans. In recent years, however, some growers in major tree-producing states like North Carolina and Oregon have struggled to remain profitable amid a looming shortage<\/a>. <\/p>\n\n\n\n

Experts with the National Christmas Tree Association and NC State Cooperative Extension<\/a> say the shortage is partly a result of the 2008 recession when decreased demand led growers to plant fewer seeds. Seeds are harvested from the cones of mature Christmas trees \u2013 and because it can take several years for trees to reach maturity, the shortage is likely to continue beyond 2019.   <\/p>\n\n\n\n

In North Carolina \u2013 which is the second-largest producer and exporter of Christmas trees \u2013 growers face changing weather patterns, diseases, and a number of other challenges that could potentially prolong the shortage. That includes parasitic wasps that eat the seeds of Christmas trees before they ever get the chance to grow. <\/p>\n\n\n\n

Originally described in the 1930s, Megastigmus specularis<\/em> is one of several thousand species of chalcid wasps. It mostly infests Fraser fir trees in the Appalachian Mountains, according to Dr. Lilian Matallana, a research associate at NC State\u2019s Department of Forestry and Environmental Resources. <\/p>\n\n\n\n

\"Microscopic<\/a>
Female Megastigmus specularis isolated from Fraser fir seeds in the Molecular Tree Biology Lab. Photo by Matt Bertone of the NC State Plant Disease and Insect Clinic.<\/figcaption><\/figure>\n\n\n\n

The tiny wasp \u2013 about 3 mm long \u2013 overwinters in fir seed on the ground, with adults emerging in spring. Females then fly to developing cones and use an elongated ovipositor (like a modified stinger) to drill into the seeds and deposit their eggs. Once the egg hatches, the larvae feed on the seed until they\u2019ve matured. <\/p>\n\n\n\n

Matallana said this cycle \u2013 which leaves seeds inviable for commercial planting \u2013 is repeated annually except some larvae delay emergence for an additional year or more, presumably to preserve the species in case of crop failures.<\/p>\n\n\n\n

Feasting on Fraser Firs<\/h2>\n\n\n\n

Until recently, there was little reason to be concerned about Megastigmus specularis<\/em> and similar species in North Carolina, according to Matallana. But, because of increased interest in growing Fraser fir for Christmas trees, information about the effect of these insects on the state\u2019s seed supply is needed. <\/p>\n\n\n\n

North Carolina produces more than 6 million Christmas trees each year, about 15 percent of the nation\u2019s natural Christmas trees \u2013 second only to Oregon. Nearly all of the state\u2019s trees \u2013 96 percent \u2013 are Fraser firs, mostly grown in 14 mountain counties. <\/p>\n\n\n\n

The state\u2019s Christmas tree industry is mainly supplied with seeds from natural stands and genetically-improved material from clonal seed orchards, according to Matallana. Trees derived from clonal seed orchards have more desirable characteristics than trees that originate from seeds collected in natural stands. These attributes provide a considerable increase in income for Christmas tree plantation owners across the state. <\/p>\n\n\n\n

Watch: Parasitic Wasp Larva Emerges from Christmas Tree Seed<\/h3>\n\n\n\n
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