JBP Problem

[subie23]

Hi all,
I'm in Sydney and last week I noticed 1 of the JBP needles turn brownish colour (refer photo) and I want opinion on what is the root cause of this? I watered the plants every 2 days during winter and I wasn't sure if this is the root cause as other JBP seems fine.

I also noticed one of the JBP have white stuff appears at the end of the candles (reer photo) and I hoping someone could tell me how to treat this

Brian

[Promethius]

Hi Subie

First one may be a root problem, especially a fungal one. Usually JBPs prefer a drier root system. Second-daily watering over winter seems excessive. I see you’re also using an insulating coir fibre mat. This will keep the soil wet too. Stick your finger a few cm into the potting mix when you’re due to water - is it still moist?

Second photo has limited resolution, but I think it looks like wooly aphids. An oil spray like Eco-oil should help.

How much sun do they get? Poor airflow and limited sun may predispose to issues like these.

[shibui]

2nd Photo is definitely too poor to give an accurate diagnosis. White stuff on pines is often Pine bark adeljid (similar to woolly aphid but not quite the same) BUT, they are usually found on the stems rather than on the new buds.
Pines can also develop white resin on the candles. Without a closer look I can't be definite but I'd lean toward non harmful resin.

Agree that brown needles at this time of year could be root damage, often caused by soil being too wet for a long time. Watering pines by the calendar is very likely to result in root rot. Need to water according to soil moisture which can mean twice a day in warm weather down to once a month in winter.
Dothostroma - AKA needle blight is another problem that may cause brown needles. Again, the photo does not show enough detail to pick up any of the tiny indicators.

If you can get some good, clear close up shots that would make diagnosis much more accurate.

[subie23]

Thank you for the feedback. With the root issue, is there anything I need to do besides changing and monitor the watering regime?

[treeman]

Yes I think watering every 2 days in winter might be the cause. Let it dry out even if it means taking it out of the pot for a couple of days. If the roots are very bad, you might want to repot into a small pot with a good mix and preferable into a terra cotta pot and include mycorrhizae from a healthy pine. The roots should have only about 2cm between them and the inside of the pot regardless of the size about ground. That is the secret of keeping many plants (including azaleas) healthy and moving.

[Albo]

I had similar problems with black pines and I think I’ve figured it out now. It’s all to do with the watering. They really don’t like being wet too long.
The main thing I did was reduce pot size as treeman said and let them get on the dryer side before watering.
Also if you know it’s going to rain a few days in a row, move them under the eves of the house so they are still in direct sun but get only a little rain.
I too am in Sydney and that 3weeks of rain in August would not have helped you one bit.
I have found the black pines are really the only trees I have that I need to worry about overwatering.