Pyrrhalta viburni Paykull, a new landscape pest in the United States, feeds in both the larval and adult stages on foliage of plants in the genus Viburnum. We measured lifetime oviposition capacity of mated and unmated females reared in the laboratory versus Þeld-collected females, as well as ovipositional response to physical characteristics of the host plant. Both mated and unmated females produced eggs, but at different rates. Field-collected females and mated females reared in the

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... laid similar numbers of egg masses containing similar numbers of eggs, but unmated females laid approximately one half as many eggs, the result primarily of smaller clutch size. Mated females reared in the laboratory had a preovipositional period of 11.4 Ϯ 1.7 versus 29 ϩ 11.7 d for unmated females, and unmated females lived signiÞcantly longer than mated females. The angle and diameter of stems of V. trilobum, a very susceptible host, both greatly inßuenced oviposition; females laid most eggs on vertically oriented stems, and those of smallest diameter; when these factors were combined, stem diameter predominated. Females also had a very strong geotactic response, preferring to lay eggs on portions of stems toward gravity, even when stems were at fairly shallow angles. Fig. 3 . Localization of egg masses on stems in the stem angle experiment; "upper" is the quadrant of the stem crosssection away from gravity, "lower" is the quadrant facing gravity, and "sides" are the two quadrants in between. Bars accompanied by the same letter (within each group of three bars for each angle) are not statistically different as determined by ANOVA followed by LSD multiple comparison test. 524 ENVIRONMENTAL Vol. 37, no. 2 ENTOMOLOGY