|Wraight, Stephen - Steve|
Submitted to: Environmental Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/24/2010
Publication Date: 10/4/2010
Citation: Jandricic, S.E., Wraight, S.P., Bennett, K.C., Sanderson, J.P. 2010. Developmental times and life table statistics of Aulacorthum solani (Hemiptera: Aphididae) at six constant temperatures, with recommendations on the application of temperature-dependent development models. Environmental Entomology. 39(5):1631-1642. Interpretive Summary: In recent years, the foxglove aphid, Aulacorthum solani, has increased from an occasional pest to a major pest in many agricultural crops. A 2006, survey of floriculture greenhouses conducted in Massachusetts and New York, identified A. solani as the second most common aphid pest of floriculture crops. Effective management of this emerging pest will require a greater knowledge of its biology than currently exists. No complete life table studies of this species have been completed, nor has its development been characterized on an ornamental crop. Extensive studies were conducted to define environmental effects on population growth and development. This information is needed for comprehensive evaluation of the biological control potential of foxglove aphid natural enemies, including predatory midges and beetles, parasitic wasps, and fungal pathogens, whose effective use requires identification of vulnerable life stages and consideration of pest population growth statistics.
Technical Abstract: Developmental rates and age-specific life tables were determined for Aulacorthum solani (Kaltenbach) (known as foxglove aphid or glasshouse potato aphid) at 6 constant temperatures feeding on pansy (Viola × wittrockiana) (Gams.). Previously, there were no complete life table studies of this species, nor has its development been characterized on an ornamental crop. Aulacorthum solani developed fastest at 25 degrees Celsius, passing through the four nymphal instars in an average of 6.9 d. The nymphal developmental period was 11.4 days at 15 degrees Celsius. Average durations of the 1st, 2nd, 3rd, and 4th instars were 2.0, 1.3, 1.4, and 2.1 days at 25 degrees Celsius, and 3.3, 2.4, 2.5, and 3.2 days at 15 degrees Celsius, respectively. The highest intrinsic rates of population increase (0.410 and 0.445) and shortest population doubling times (1.69 and 1.56 days) were recorded at 20 and 25 degrees Celsius, respectively. Using the Lactin equation, the lower developmental threshold was estimated at 4.0 degrees Celsius and the upper threshold at 35 degrees Celsius; the developmental optimum was calculated to be 25.5 Celsius. Average total fecundity was highest at 10 and 15 degrees Celsius (74-75 nymphs/adult); reproduction dropped slightly to 68 nymphs/adult at 20 degrees Celsius, but the decrease was not statistically significant; a significant decrease to 39 nymphs/adult occurred at 25 degrees Celsius. Fecundity and intrinsic rate of increase are likely to be higher under natural greenhouse conditions.