Question
QUESTION: Good morning Mr Parker, I'm living in Pretoria, South Africa. I have a few Johannesburg Gold Conifers, height ? meter. I treat them every year from March to July for these bark beetles. The branhces turning brown every year but now I have noticed that some of the bottom branches are still green at the end but from the trunk to the middle the branch seems dead. Can it happen that the branch from the trunk to the middle can be dead and still be green in the end? How can I prune these branches or must I leave them and they will grow again.

Regards
Maria Papenfus

ANSWER: Good Morning Maria, and thanks for the question.
First, it抯 important to know exactly what the genus and species/cultivar is of the conifer(s) in question. If you don抰 know the species that alright, but I need to know if the conifer(s) are pines, spruces, firs, cedars, junipers, or what.  Although you undoubtedly deal with different pests than I do here in the United States, I can give you better advice with the more information I get.

Secondly, do you know if the tree was actually infested with bark beetles or do you apply pesticides to the trees preventatively? A little more background on the trees will be helpful for me.

In answer to your initial question about whether the branch is dead or not, if it has new growth at the tips then it抯 still alive. I have seen in many cases where conifers will die back from the trunk to the tips.

As soon as you get me some more information I can try to give you some direction.

Thanks
James


---------- FOLLOW-UP ----------

QUESTION: Good morning James,
Thanks for your prompt response. Sorry I did not give you the correct names.
These trees are ?m by 1.5m and they are a yellow colour with green here and there. Three of are planted next to each other in a space of about 5m by 3m They look very healthy from the outside. It is only the inside that is brown. The correct name for them is Cupressus macrocarpo 'Goldcrest'. I hope this will help.
The name of the bark beetle is the Italian Cypress Aphid. You are right. I apply Ekfekto's Aphide by spraying the foliage and also apply Efekto's Insecticide granules to the base of each tree preventatively during March and April every 14 days and until July then once a month.
Normally I'm successful but this year I noticed that some of the branches do not have foliage except at the ends and look dead from the middle of the branch up to the trunk. I assume then if I cut off all this dead wood at the beginning to the middle of the branch new foliage should appear.
Except for the above I don't have any problems with my conifers.

Kind Regards
Maria

Answer
Hi Maria,

I抦 quite envious that you抮e able to grow such a magnificent species. I抳e seen Cupressus macrocarpo (Monterey Cypress) in its native habitat of California and it抯 quite a striking tree.

In answer to your comment about pruning dead wood, don抰?ever be scared to remove wood that you抮e sure is dead. That is a universal horticultural and arboricultural principle. However, ascetics are also important considerations when undertaking any pruning. Sometimes removing deadwood can leave a tree or shrub looking thin after removing the dead branches.

Also Cupressus macrocarpo does NOT bud from old wood, meaning that if you prune it back to where there isn抰 any green foliage visible, it will effectively kill that branch.

My suggestion going forward with this tree is to continue your regiment of pesticide applications for the Italian Cypress Aphid at whatever the label rate prescribes. In addition be sure that you抮e providing the tree with adequate water. I read somewhere recently about Pretoria (Tshwane) having record setting temperatures as of late. If this is the case, some of the dieback you抮e seeing on this particular specimen might be due to drought related stress because of some inefficiency in its root system. Remember, Cupressus macrocarpo抯 native environment is in fog laden coastal region of the central California coast. Although they can tolerate periods of dryness, prolonged periods will stress them to the point they might begin shutting down areas of the tree that are deemed non-essential to survival (inner growth would fit into this category).

I wish you all the luck with your tree and I hope that my advice is useful.

Best Wishes
James