Posted by H.H.Gardener on July 16, 2002 at 22:35:55:
In Reply to: arborvitae problem posted by scott fisher on July 16, 2002 at 17:10:22:
It is possible to be either problem. I suggest you place a piece of white paper under a branch and tap the branch. If you notice any moving speck, it is spider mites. Also look for any brown cone type shaped little sacks, this would be bagworms. If neither is the problem, then you more than likely have a fungal disease. For the insect infestation, if it is Bagworms, you can use Dipel (BT) or the liquid form Thuricide, which is organic and not toxic. Add 2 Tablespoons of Flour and 2 Tablespoons of Sugar to the Dipel, along with a drop of liquid dish washing soap.
For spider mites, they are more difficult to control. I recommend the product Neem (azadirachtin) which is also organic, but has inert ingredients, so cannot be use of food products. In order to eradicate the spider mites, you MUST apply the chemical every 3 days and spray for a total of 3 sprays, they multiply that fast in warm weather. A forceful spray with the water hose, spraying under the foliage will assist in knocking the pest off, but do not do that after you have applied the chemical. You can use the hose technique after you have the spider mites under control.
If insects are not the problem, then I recommend the application of Daconil 2787 fungicide, which is a broad spectrum fungicide controlling several diseases. Re-apply in 7 days and possibly another application for good control. Always spray insecticides, or fungicides, later in the day, so the hot sun and heat does not cause a foliar burn and make sure the plants roots are not dry prior to application. Good luck.
: I have a wall of arborvitae about 30 feet long and 10 feet high. On 2 or 3 trees the lower branches are turning brown on the tips and then the full branches. Branches just starting to brown appear to be browning in random speckling pattern, and then engulfing the leaflets in total dead browning.Do you feel this disease is more insect or fungal in nature.Any help would be appreciated. Thanks