Nyssa scale

Systematic position: The Nyssa scale (Chionaspis nyssae) is a member of the Diaspididae family within the order Hemiptera. These insects are characterized by a protective waxy cover, or scale, which they secrete to protect themselves from environmental stressors and predators during their sedentary adult stage.

Host plants: The primary host for this pest is the Nyssa tree (Nyssa), including the black tupelo. They are typically found on the bark of twigs and trunks. Due to their host specificity, they are primarily of concern in nurseries and landscape settings where these trees are planted for their aesthetic or ecological value.

Biology and life cycle: The life cycle consists of egg, nymph (crawler), and adult stages. Females remain under the scale, laying eggs that develop into crawlers. Once these crawlers emerge, they move to find a suitable feeding site on the plant, insert their stylets into the tissue to feed, and then initiate the development of their own protective scale.

Damage and pest impact: Damage is caused by the extraction of phloem sap from the host plant. This feeding process stresses the tree, leading to decreased vigor, bark cracking, and branch dieback. Severe infestations can significantly reduce the overall health of the tree, potentially making it more susceptible to secondary pathogens or environmental stress.

Control measures: Management involves a combination of monitoring and chemical interventions. Applications of horticultural oils can be effective against overwintering stages or by disrupting the protective layer. Systemic insecticides are also commonly used during the crawler emergence phase to ensure effective coverage. Maintaining tree health through proper irrigation and fertilization is crucial for plant resilience.