More questions about my White Oak saplings.

[pharmvet]

Some of the White Oak trees I planted last spring have developed white crumpled leaves. Today I sprayed them all with malathion and some Ortho solution that is supposed to kill all kinds of fungus etc. From looking at the pictures, what would you surmise is the cause of this?




On another note, notice how the trees pictured below have formed offchute branches that have taken over and are the most upwardly growing limb. If I trim the other limbs this winter and allow the dominant limb to essentially become the main trunk, will this be a straight trunk by the time the tree is 10" in diameter, or will that offset be ever present in the trunk of this tree?

 

[SPIKER]

The offset truck will probably appear there for live of tree but diminish with size. Part of the problem for that is it is growing in open field/yard where it will grow bushy almost no matter what you do. Only trim off about 20% of the tree's branches/foliage per year and should only trim this much every other year.

Not sure what you sprayed on them but might have caused some burn on the leaves and or over fertilized them. They almost look like there was too much salts in the solution to me.

Mark

 

[HarryN]

I do not believe the Malathion is a fungus control solution. It is a insecticide. Did you see some bugs on them?
May not have done any harm to spray that though.
Good pictures..... some one should have an answer for you.

 

[Fossil Farm]

Almost looks like spray drift damage to some degree. If you were in the north, I would suspect frost damage as another possibility. Are there hard spots on some of the leaves, like oak gall? Hard to tell from the photos. Might be worth taking a couple examples to the extension office or a good garden center. Anything on the bottom of the leaves, such as black spots or insects?

The main leader probably died or a bird landed on it and killed it, so you have lateral growth. Around here, spring is the time to prune and allow only one leader to take over. Not sure what the best time to prune in Texas would be. In the north, you want the cut to heal as much as possible before winter cold.

 

[mjw357]

In the north, you want the cut to heal as much as possible before winter cold.

Yes, early spring is the best time to prune. The tree's sap seals the wound to keep out infection and rot.

 

[bigtiller]

The Iowa State Extension Office is who I would take tree trimming advice from. They say oak trees should be trimmed mid to late winter to avoid oak wilt which is passed on by a small beetle.

ISU Forestry Extension - Care and Maintenance: Pruning Young Landscape Trees

Coppied from ISU web site:

When To Prune
The best time to prune is in mid to late winter (January-March). When pruned during this time of the year, the tree will begin responding to the wounding early in the spring. A coniferous tree planted in a suitable site, will need minimal pruning throughout its life.

Pruning at other times of the year will not hurt a tree; however the process of sealing the wound may be slowed. Do not prune during the spring from bud break through leaf expansion, and during the period of leaf color change in the fall. A tree is going through major changes at these times, and branch removal can reduce the vigor of a tree. One species where timing of pruning is critical, is oak. The pathogen that causes the disease Oak Wilt can be transmitted to open wounds by a small beetle. Avoid wounding (pruning) oak between early March until late July.