Your Name - Bio 230


Nutrition and Host Interaction

The nutritional needs of the Viburnum clearwing borer are provided by consuming the stem bases of the American high bush cranberry and other Viburnum shrub.  According to entomologist Jeff Hahn, when in the larval stage, the immature caterpillars tunnel from the soil line to several inches below the soil containing the roots of the Viburnum plant, and then enter the plant by boring holes into its bark and cambium (2003).   According to Phil Pellitteri of the UW Insect Diagnostic Lab, the larvae have the ability to attack the plant from below the soil line to upwards of 18 inches off the ground.  Chewed, swollen, scarred stems and emergence holes appear on the plant and give evidence of a borers’ attack (1999).  Once a bush is severely attacked, it shows physical signs of bare foliage and dieback which can lead to the plant’s death.  Some plants are able to survive borer attacks but often show signs of callused healing and old scarring (Pellitteri, 1999).

However, in a research study by Hartman and Parsons in 2005, Virburnum plants located in the community of Green Bay, Wisconsin were donated to the study and dissected for observation of Virburnum borer damage.  They found that unlike the current literature on the feeding behavior of the borer, evidence found that borers did in fact create galleries in the cambium of the plant, but also seem to prefer the areas where the plant is attempting to callus over and heal its damage.  Hartman and Parsons hypothesize that this is because the bug prefers this area containing plant growing material which is extremely nutritious (Hartman et al. 2005).  Additionally, their observations have lead to the hypothesis that plants baring signs of previous Virburnum borer damage are sought out and preferred by adult egg laying Virburnum moths.  Therefore, once a plant becomes infested, it has a high probability of never escaping invasion and eventually dying from the damage (Hartman et al., 2005).

Often, a Viburnum borer will prey on unhealthy and weak bushes verses healthy, successful counterparts (Pellitteri 1999).  As D.A. and M.F. Potter of the University of Kentucky point out, a borer is able to dramatically decrease the health and possibly kill a Viburnum plant by damaging the plant’s vascular system.  The vascular system is located just behind the bark of the shrub and is responsible for carrying the proper nutrients throughout the plant for survival.  When the vascular system is eaten away by the borer, the tree is unable to effectively distribute its metabolic needs.  Therefore, in a relatively short time ranging from one to three years, the plant can lose its ability to function properly and die (Potter et al., 2008). Because of the nature of the dietary behavior of this insect, it has been regarded as pest species leading to the destruction and reduction consequences it has for Viburnum plant species.  Records show documentation of considerable damage in the states that encompass the Great Lakes Region (Etes 2012). 

David Parsons, University of Wisconsin, Bugwood.orgDavid Parsons, University of Wisconsin,

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