On a dreary wintry day, nothing quite compares with a fragrant evergreen to add cheer to a home. The tradition of bringing an evergreen tree indoors probably dates back to the 1500’s in Eastern Europe. During these times, small fir trees were brought inside and decorated with natural ornaments such as apples and nuts. In warm climates, where winter’s cold and snow are scarce, the tradition of “flocking” an evergreen with artificial snow helps some wistful celebrants keep the season merry. Imagine my delight when I discovered a lovely pine tree wearing a wonderful coat of flocking designed by Mother Nature herself. Despite the fact that snow had not fallen, every bough and branch of the beautiful tree was covered with white. Closer examination revealed that this was not the work of Jack Frost, but a remarkable infestation of pine needle scale.
Red crawlers search for a place to settle down.
Pine needle scale belongs to a clan of insects known as armored scales, so named for the hard waxy shield covering the dorsal surface of their body. During the holiday season, the pine needle scale survives as red eggs nestled snuggly beneath the white waxy cover of their mother. In spring when temperatures warm, eggs hatch and small red nymphs called crawlers leave the protection of the cover. They move to an unoccupied location on a pine needle, insert a soda-straw-like beak into the plant tissue and begin to suck fluid from the needle. After finding a suitable spot, they hunker down, shed their skin, and produce white wax from dozens of tiny pores lining their bodies. Once settled, females are destined to spend their entire life in one spot never to develop wings or roam again.
After killing the scale, tiny wasps emerge and leave round holes in scale covers
In contrast, once their time as juveniles is complete, male armored scales emerge from beneath their waxy covers as winged adults that resemble small flies. Their mission is to find willing mates. In temperate locations like Maryland, the pine needle scale completes two generations a year. Infestations of pine needle scale tend to be much heavier in simplified locations such as landscapes and Christmas tree plantations compared to natural settings such as forests. Just as in a fairytale by Grimm, the forest is a dangerous place for scales where predators such as lady bugs and crickets abound. These voracious scale eaters may help keep populations of pine needle scales at bay in natural settings. You may also see some pine needle scales with tiny round holes in their covers. This is where murderous parasitic wasps have emerged after killing their scale victims. Look carefully at the needles of your Christmas tree if you have one and if you dare. You too may be fortunate and find natural decorations and some high drama on the tree.
References:
The interesting article “Influence of Plant Community Structure on Natural Enemies of Pine Needle Scale (Homoptera: Diaspididae) in Urban Landscapes” by John Tooker and Lawrence Hanks was used as a resource for this Bug of the Week. To learn more about pine needle scale, please visit the following web site.