Conifer disease

[Neil]

Does anyone have any idea what may be happening to three of our young conifers? In the last couple of days we have noticed some browning and dying of needles on the end of branches, usually (but not necessarily) on the current year's growth. The top of the oldest tree (about 8 years old) looks ragged, which suggests that the condition may have been in existence for some time. On the two youngest trees (about 3 or 4 feet tall) the new growth turns light green and then yellow/white before browning and dying. I have thought of Diplodia tip blight, but I haven't been able to find any pictures of that on the internet. I have not seen any black fungal fruiting bodies on any of the trees. I append a few pictures. Three is the maximum number of pictures I can post, but I can e-mail others to anyone who may be interested (contact me on [email protected]). Neil

[Neil]

Further to my earlier post about the condition affecting some of our conifers, I have received a response to an email that I sent to friends who have a large area (about 200 acres) of commercial woodland. This is what they said:

"We think it is definitely not red needle blight, definitely not aphid stripping as both involve old needles. It has not the appearance of Phytophera and we are pretty certain that it is end tip disease which is a result of stress - extreme alteration in weather etc. We would leave well alone a this stage and see if it recovers as the weather improves. You did not say if any particular conifer is affected although the pictures suggest it is widespread. We have red needle blight in our corsican and this is far worse in wet weather and we get almost complete recovery when it dries out - but here we have had intense cold (snowed three weeks ago) and monsoon conditions and one week of blazing sunshine."

I'm not sure about this. The condition is not in fact widespread. It affects one fairly tall tree which stands only a few feet away fom several others which are (so far) unaffected, and two smaller one which are some thirty yards away and not near other conifers. We have not suffered extremes of weather: a fairly hot period commenced and ended gradually, and rainfall has been adequate and never torrential. In any case, if climatic stress is the cause, why aren't our other confiers also affected?

My feeling is that, to be on the safe side, we should fell the tall affected tree, and try treating the two smaller ones. The treatment I have in mind for them is removal of the brown tips (not difficult because the trees are no more than 4 feet tall) followed by administration of a copper-based fungicide (Bordeaux mixture, probably). If anyone has other suggestions, I would be very pleased to hear them.

[Neil]

Following up my previous two posts, we have just noticed a similar condition affecting two rowan trees on our land, and this makes me think that it may not be a fungal disease after all, but possibly just the aftereffects of one or two late frosts that we experienced a few weeks ago. Our land is quite high and the trees come into leaf late compared to those in other woods in the area, and so the buds on some trees could well have been at a critical stage when the frosts occurred. Our lastest thinking, therefore, is to wait and watch, rather than to do any felling or anti-fungal treatment. I'll update the posts on this topic when or if the situation changes. Neil.

[splodger]

i think you are right about it being weather damage neil - just keep an eye on the trees, just in case there is any deterioration

[Stephen1]

This is almost certainly frost damage Neil. You get genetic variation in the timing and speed (and therefore stage) of development between individual trees of the same species - so you can have two individuals of the same species side by side and only one is damaged - which can lead people to dismiss the idea of frost being the cause.With conifers the damage caused by frost can take many weeks to become apparent to a casual inspection. I genuinely wouldn't worry about this if I was you.

[Neil]

Thanks, Stephen. That's reassuring. Certainly the condition has not progressed, as I would have expected it to have done had a pathogen of some kind been at work. So we're just keeping an eye on it. Neil

[Neil]

An update on our conifers. All the ones showing brown tips recovered perfecly as the year wore on, and are all now fine. However, we'll keep a close watch on them and see how they progress in 2013. Neil