Effect of host plant ozone stress on Colorado potato beetles

Effects of ozone (O-3) stress of potato, Solanum tuberosum L, on fecundity, larval growth and survival of Colorado potato beetles, Leptinotarsa decemlineata (Say), were measured in greenhouse and field experiments. Chronic O-3 exposure caused moderate to severe foliar injury on an Q,3-sensitive cultivar ('Red Norland') but caused only minor injury an O-3-resistant cultivar ('Superior'). Foliar injury caused by O-3 was greater on old than on young leaves but feeding by adult beetles was greater on young leaves in all experiments. Foliar analyses of the five uppermost leaves (nodes. 1-5) showed higher carbon (C) and higher nitrogen (N) concentration in Superior than in Norland. There were no significant O-3 effects on C or N and no cultivar X O-3 interactions. Egg production by newly emerged adult beetles feeding on plants exposed to high O-3 levels was not significantly different from egg production on plants exposed to low O-3 levels, regardless of cultivar O-3 sensitivity. Feeding and energy conversion efficiency of neonates and survival of larvae, to the adult stage were not significantly affected by the O-3 treatment. Although present levels of tropospheric O-3 are high enough to significantly affect yield of sensitive potato cultivars, our results indicate no significant effect of ambient O-3 Concentrations on Colorado potato beetle populations.