Date of Award
Master of Science
P. L. Lambdin
C. D. Pless, R. R. Gerhardt
The biologies of two soft scales, Coccus hesperidum Linnaeus and Toumeyella liriodendri (Gmelin) (Homoptera: Coccidae),and three armoured scales, Chionaspis kosztarabi Takagi and Kawai, Pinnaspis aspidistrae (Signoret), and Quadraspidiotus juglansregiae (Comstock) (Homoptera: Dia-spididae), were investigated at the University of Tennessee, Agricul-ture Campus using populations in Tennessee. All studies were conducted from 1975 to 1976 except those for T. liriodendri were from 1973 to 1976. The brown soft scale, C. hesperidum, was a multivoltine parthenogenetic species on spider plant, Chlorophytum comosum Wood. There were seven to eight generations per year. One mite species was collected in close association with the brown soft scale with no parasites or predators found. Biological studies revealed the tuliptree scale, T. liriodendri, to be univoltine and ovoviparous on yellow-popular, Liriodendron tulipifera L. overwintering as first and second instars. Four Formi-cids, one Dipteran and one Hymenopterous wasp were found collecting honeydew produced by the tuliptree scale. The tuliptree scale was parasitized by three Hymenopterous species and one Dipteran and preyed upon by one Lepidopteran and four Coccinellid species. Two other Hjnnenopterous parasites and one mite were collected in close associ-ation with this species. Chionaspis kosztarabi was bivoltine and oviparous on white ash, Fraxinus americana L., overwintering as fertilized adult females. One Hymenopterous parasite was found parasitizing C. kosztarabi second instar females and one scavenger mite was found in close association with adult females. Studies revealed the fern scale, P. aspidistrae, to be a multivoltine parthenogenetic species on lilly turf, Liriope spicata, over-wintering as adult females. One Hymenopterous parasite was found parasitizing second instar females. The walnut scale, Q juglansregiae, was bivoltine and oviparous on flowering dogwood, Cornus florida L.,overwintering as second instar males and females. One Hymenopterous parasite was found parasitizing second instar females. Three mite species were found in close associ-ation with this species. Seasonal history tables of the four latter species are included along with photographs of each biological study and mounting methods. All nymphal instars and adults are discussed. Selected chemical insecticides were evaluated in greenhouse studies in 1975 to compare their efficiency in controlling brown soft scale on C. comosum and fern scale on L. spicata. Insecticides tested were orthene 75W, two rates of carbaryl 50W, and dimethoate 2E. All chemi-cal treatments gave effective control of both species.
Simpson, Joe Davenport, "The biology of five scale insects (Homoptera : Coccoidea) in Tennessee. " Master's Thesis, University of Tennessee, 1976.