Hi, we have Backyard Bliss Lilly Pillies and have noticed leaves at the trunk and base of the tree becoming spotted, then dropping off. We regularly water (2 x week at the bases of the plant) and use seaweed solution once a month. We have lots of new growth otherwise on the trees. The spots aren’t raised and I can’t seem to see anything significant on the underside of the leaf. I am not sure whether to use white oil or if this could be a fungal infection? Or perhaps an under/overwatering issue? Can you please provide advice on how to manage this. I can’t seem to find similar pictures on any other forums for Lilly Pillies and don’t want the problem to progress further. Thanks very much in advance!
Hello @SarahMac
Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your Lilly Pilly.
Thanks so much for the detailed description and photos, that really helps. From what I can see, the yellow mottling with fine green speckling across the leaf surface, especially starting on the lower and inner foliage, looks much more consistent with sap-sucking pest damage, particularly lace bug or possibly spider mite, rather than a fungal issue or watering problem.
The pattern is quite distinctive. Fungal leaf spots on lilly pillies usually appear as defined brown or black lesions with clearer edges, sometimes with a halo. What you’re showing is more of a stippled, mottled yellowing where the green pigment has been sucked out. The fact that the spots aren’t raised and there’s no obvious fungal growth underneath also points away from a fungal disease. With lace bug especially, the upper leaf surface develops this speckled look while the insects feed on the underside, and they can be surprisingly hard to see unless you look very closely.
It’s also worth noting that the damage is occurring on the inner and lower leaves near the trunk. That’s typical of pests that prefer sheltered areas. The good news is that you’re seeing strong new growth, which means the plants are generally healthy and not under major stress from watering.
At this stage I would recommend treating for sap-sucking insects rather than using a fungicide. A good option is Yates Nature’s Way Citrus & Ornamental Spray (special order), which is based on pyrethrum and safe for use on lilly pillies. If you prefer a more general pest oil approach, Yates 750ml Ready To Use Pest Oil can also be used.
Whichever product you choose, make sure to spray both the upper and lower leaf surfaces, concentrating on the inner canopy where the damage is showing. Apply in the cooler part of the day and repeat as directed on the label, as one application is rarely enough to break the cycle.
In terms of watering, twice a week at the base sounds reasonable depending on your soil type and weather. Overwatering typically causes more uniform yellowing rather than speckling like this. If the soil drains well and the new growth looks healthy, your regime is likely fine. Just avoid keeping the root zone constantly wet.
You can also prune out the worst affected inner leaves to improve airflow and remove some of the pest population. Dispose of the pruning's rather than composting them.
The overall outlook is very positive. Lilly pillies are tough plants and respond well once the pest pressure is controlled. With a targeted treatment and a follow up spray, you should see the new growth remain clean and the problem settle down.
Please remember to wear personal protection such as gloves, goggles and mask when spraying your plants.
If you need further assistance, please let us know.
Eric
@EricL Hi Eric, thank you so much for such a detailed response and your recommendations. It’s a relief to hear that the overall outlook is positive! I have bought the Yates 750ml Ready To Use Pest Oil. It’s not very clear on how often to re-apply. After one application, when would you expect to see any improvement? Will the leaves that have already started to be affected return to normal or is the spray likely to just prevent further infestation?
Should I remove the most affected leaves (which may leave the centre portion of the branch closest to the trunk bare)? Would you expect new growth to appear along the central portion of the branch again?
Thanks again for your help!
Sarah
The spray will generally prevent further infestation. The average time between sprays is 7 to 14 days. You'll need to judge if the infestation is getting worse. If it is, then a shorter time between sprays will be necessary. I'm sorry but the affected leaves will not return to normal. Recovery time for each affected plant is different, but I would conservatively give it a few weeks.
It would be best to remove the affected leaves to reduce the infestation. Please make sure to bin these leaves and not mix them with your compost. As for the centre portion a bit of light tip pruning is recommended to encourage growth and colourful new foliage.
