Farm Forestry New Zealand
PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Monitoring Monterey Pine Aphids
FHRC Project: 2000-01.
Date: September, 2001
Author: T. Herman, M. Davidson and C. Appleton
Publication: Crop & Food research Confidential Report No. 485
Project reference: 2000-01
Full report is available from:
Crop & Food Research
Private bag 4704
Christchurch
New Zealand
Executive summary:
This report presents the results of a monitoring programme to determine the pest status of the Monterey pine aphid, Essigella californica (Essig), in Pinus radiata plantations in Hawke´s Bay. This programme was developed in collaboration with Forest Research scientists, who are undertaking similar work in radiata forests in the Bay of Plenty.
Monterey pine aphid populations were monitored in forest stands of three ageclasses within three elevation categories between October 2000 and April 2001 to assess levels of infestation and defoliation in pine plantations in Hawke´s Bay. The aphid sampling and canopy evaluation protocols were similar to those used by Australian researchers. The former involved beat sampling lower branches, followed by scoring the number of aphids. The canopy scoring protocol required a visual estimate of the level of defoliation in the current season needles and older foliage.
Winged aphids were collected weekly from a suction trap located at Ngatawara, approximately 8 km west of Hastings and between 40 to 60 km from the forests surveyed. Winged aphids were also collected weekly from similar suction traps located in Canterbury - one at Lincoln, approximately 14 km east of the nearest pine forest, and another at Courtenay, approximately 5 km south of a pine forest.
Peak aphid scores were recorded in January through to February, and this coincided with a peak in flight activity based on the Ngatawara suction trap catches. However, only small numbers of aphids were recorded (<100) from the beat samples. No defoliation was observed in any of the pine stands surveyed. There was no apparent significant economic effect of Monterey pine aphids on the growth of Pinus radiata based on results from aphid and canopy scores during the 2000/01 season.
Full report is available from:
Crop & Food Research
Private bag 4704
Christchurch
New Zealand
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