|Jandricic, Sarah -|
|Mattson, Neil -|
|Sanderson, John -|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 30, 2014
Publication Date: April 14, 2014
Citation: Jandricic, S.E., Mattson, N.S., Wraight, S.P., Sanderson, J.P. 2014. Within-plant distribution of the Foxglove Aphid (Aulacorthum Solani Kaltenbach) (Hemiptera: Aphididae) on various greenhouse plants with implications for control. Journal of Economic Entomology. 107:697-707. Interpretive Summary: Foxglove aphid (Aulacorthum solani) has recently undergone a status change from an occasional pest to a serious pest of greenhouse crops in North America and the UK. Consequently, little information exists on the ecology of this insect in greenhouse crops. Although previous reports have suggested that foxglove aphids prefers to feed on new growth of plants, our earlier studies revealed a strong preference of this aphid to feed on the undersides of the lower leaves of young, vegetative (preflowering) pansy plants, and that preference for this cryptic habitat limited the biocontrol potential of an aphid predator. To determine if this behavior is typical of foxglove aphids, we explored the within-plant feeding preferences of this pest on a variety of common greenhouse plants, including pansy, sage, zinnia, pepper, snapdragon, petunia, marigold, and poinsettia. Observations confirmed that, as observed previously on pansy, foxglove aphid generally preferred to feed on the lower leaves of young plants but revealed a preference for higher locations on mature plants (primarily flowers, flower buds, or upper leaves). These findings suggest that biological and contact-chemical control of foxglove aphid may be difficult in young crops, and will inform greenhouse growers that it may be necessary to alter scouting protocols and pest management decisions when dealing with this pest.
Technical Abstract: Foxglove aphid (Aulacorthum solani Kaltenbach; Hemiptera: Aphididae) has recently undergone a status change from an occasional pest to a serious pest of greenhouse crops in North America and the UK. Consequently, little non-anecdotal information exists on the ecology of this insect in greenhouse crops. To help inform integrated pest management (IPM) decisions, we explored the within-plant feeding preferences of A. solani on a variety of common greenhouse plants. Observations revealed this aphid generally preferred to feed on lower leaves of vegetative plants, but preferred higher locations on reproductive plants (primarily flowers, flower buds, or upper leaves). As aphid numbers were not correlated with plant biomass within each plant stratum, it was concluded that the observed differences in preferred feeding sites on vegetative vs. flowering plants were a reflection of differences in the nutritional quality of the various tissues of these plants. Despite being anecdotally referred to as “stem-feeding aphids”, A. solani were almost never found feeding on plant stems at the population densities established in our tests, with the exception of racemes of scarlet sage (Salvia farniacea). Although previous reports have suggested that A. solani prefers to feed on new growth of plants, our study indicates that mature leaves were preferred over meristem tissues on most plants. The implications of the within-plant feeding preferences of A. solani populations on both biological and chemical control are discussed.