Invasive Species Compendium

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Abstract

Flight activity of alate Adelgids (Homoptera, Aphidoidea) in southern England.

Abstract

The flight periods of eight species of Adelgids were deduced from catches in suction traps in a mixed woodland site at Alice Holt, Hampshire, from 1965 to 1970. Nine species from other natural forest areas in the northern hemisphere occurred on trees in the study area, but some immigration may have contributed to the numbers trapped. Large catches (often exceeding 200 individuals/day) of three pest species, Adelges laricis Vall., A. cooleyi (Gill.) and Pineus pini (L.), occurred during late May and June. Only small catches (less than 10 individuals/day) were obtained during July-September. The sexuparea from the non-Picea host-trees occurred mainly in May and June, whereas the gallicolae from Picea host-trees flew during certain periods from June to September. Analysis showed that the threshold temperature for flight was 16 deg C and that 64% or more of the total monthly catch was taken in the afternoon (1-7 p.m.). The variation in length of the early summer flight period by about a week was related to air temperature maxima but the fluctuation (about a week) in the mean date for flight of each species in the early summer period is probably connected with the phenological condition of the food-plant.