Plant Doctor Archive

Lumpy leaves

LAST winter we chopped back our pittosporums. The new leaves seem crinkled and have tiny yellowish round lumps on them. Should I spray?

THE yellow lumps are sap-sucking psyllids. You could spray if the plants are severely affected but most pittosporums grow reasonably well even with a sizeable population. Rather than spray, I recommend you fertilise and water in dry periods to encourage lots of strong new growth.

Psyllids prefer to feed on the new shoots so once the growth is long enough a regular trim with hedgeclippers is usually sufficient to keep the psyllid population at relatively low levels. The problem is usually worse in the heat of summer and can almost disappear with the onset of cool moist autumn and winter conditions.

If you do spray, a general insecticide such as Rogor 100, Confidor or Mavrik should give good control.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.