What's eating my cheshunt pine?

Cheshunt Pine (Diselma archeri) is a rare Tasmanian endemic rarely grown outside specialist collections. In cultivation, scale insects and spider mites are the most likely pest threats. Root rot in poorly drained soils is a greater risk than insects. No significant garden pest record exists; general conifer pest vigilance and good drainage are the primary defences.

White crusty scale colonies on foliage and stems; yellowing needles; dieback of small branches under heavy infestation. Dormant horticultural oil spray in late winter. Insecticidal soap targeting crawlers in early summer. Improve air circulation around the plant.

Fine bronzing and stippling of foliage; faint webbing between branchlets; needle drop if untreated in hot, dry weather. Keep plant well-watered; Diselma prefers cool, moist conditions. Apply neem oil or miticide spray and repeat every 7 days for 3 applications.

Notched leaf margins from adult feeding; root system damaged by larvae, causing wilting and plant collapse in containers. Apply nematode drench (Steinernema kraussei) to compost in August–October. Inspect root ball when repotting and destroy any white C-shaped grubs found.