Finally as far as pests go, Cypress varieties can be effected by the Cypress Wasp or Cypress Borer.
Normally once the problem is recognised it is usually too late. While the wasp does
little actual damage to the tree, its offspring does all the damage. The wasp lays
eggs deep in the trunks and boughs of the tree. The eggs hatch and the grub begins
munching its way to the outside. Instead of taking the same road that they came in
on, they usually wind their way just under the bark of the tree usually ring-
The tree becomes very sick with many dead boughs appearing and in severe cases the whole tree dies. Secondary diseases like canker also enter the tree through the open borer holes, compounding the trees woes.
Weeping from the open holes is visible and the tree takes on a very sick appearance.
Prevention is always the best cure. If you suspect borer action in your area, regularly spray your trees with a systemic insecticide. If an attack should occur both the parent and off spring should be killed before serious damage can occur.
Although we have never had to deal with the problem at the Laurels, advice has been received from nurseries that have had infections of this nature, that injecting effected trees with malathion (see disclaimer) has produced some success. Malathion is found in various trade mark brands of insecticide.
Malathion is chemical in the Organophosphate group of chemicals and in all fairness is not one that you should muck around with. It is highly likely that malathion in its varied trade mark forms is not available to the general public. Have a chat to your local produce store and seek advice.
My best advice is to seek the help of a professional. Have a look in your local yellow pages for an Arborist or Tree Surgeon.
However if you do take on the job yourself, you will need specialised protective clothing.