Monitoring Monterey pine aphids in Hawkes Bay forests

Abstract

The Monterey pine aphid (Essigella californica) was recently found in New Zealand To examine the seasonal biology and impact of this insect on Pinus radiata aphids were sampled using beating and branch bagging methods over two seasons (October to April) from three forest elevations and from three tree ageclasses in Hawkes Bay forests Many more aphids were found in 200102 than in 200001 with numbers peaking in January in 2001 and April in 2002 Few aphids were found from October to December More aphids were recorded on trees in the medium and old age classes than in the young age class There was no consistent pattern in aphid numbers in relation to elevation of forests There was little visual evidence of aphid damage to trees but this does not mean that this aphid does not cause economic damage Factors influencing the population dynamics of this aphid and sampling methods are discussed