Evaluation of Buffalograss Leaf Pubescence and Its Effect on Resistance to Mealybugs (Hemiptera: Pseudococcidae)

Authors

Jennifer M. Johnson-Cicalese, University of Nebraska-LincolnFollow
Frederick P. Baxendale, University of Nebraska-LincolnFollow
Terrance P. Riordan, University of Nebraska-LincolnFollow
Tiffany Heng-Moss, University of Nebraska-LincolnFollow
Lisa Baird, University of San DiegoFollow

Document Type

Article

Date of this Version

2011

Comments

JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY 84(1), 2011, pp. 71–77. Copyright 2011 Kansas Entomological Society.

Abstract

Considerable progress has been made in improving the turfgrass characteristics of buffalograss, Buchloë dactyloides (Nutt) Engelm, a native North American grass species with low maintenance requirements (Riordan et al., 1993). Two mealybugs, Tridiscus sporoboli (Cockerell) and Trionymus sp. (Hemiptera: Pseudococcidae) have emerged as buffalograss pests (Baxendale et al., 1994). Mealybugs have been associated with buffalograss stands throughout Nebraska (Baxendale et al., 1994), as well as in Texas and Arizona. Unfortunately, the Pseudococcidae are poorly described and species identification requires extensive specimen preparation (Ferris, 1950, 1953). Buffalograss mealybugs have an oblong, pale purple-grey, membranous body, ranging in length from 0.2 to 3.0 mm. They are covered with cottony wax secretions (Baxendale et al., 1994). The adult female is relatively immobile and is found inside or near the leaf sheath, or behind the leaf axils enclosing the female flower. Clusters of eggs are deposited within a filamentous waxy ovisac. First instars, or crawlers, migrate to new feeding sites and likely play a role in host selection (McKenzie, 1967). Mealybugs are often overlooked in the field because of their small size and hidden location on the plant (Baxendale et al., 1994). Severe mealybug infestations result in a general decline of the buffalograss stand, which can be confused with drought or other stresses. Initially, the turf takes on a reddish-purple discoloration, followed by browning and thinning. A close examination will reveal the mealybug’s white cottony secretions. Possible strategies for managing mealybugs on buffalograss include pesticides, biological control, and use of resistant buffalograsses. Developing mealybug-resistant buffalograsses is of particular importance because this grass is used primarily as a low-input turfgrass species. Fortunately, several resistant buffalograsses have been identified (Johnson-Cicalese et al., 1998). Understanding the mechanism of this resistance would be helpful for formulating optimal strategies for identifying and exploiting new sources of resistance. While considerable progress has been made in identifying germplasm resistant to insect pests, progress toward characterization of the mechanisms conferring the resistance has been limited.