Question
Approximately four years ago we noticed a lot of dead, black leaf drop from the six 15 year old Bradford Pear trees we have lining our driveway.  The trees are very thinly leafed now.  Someone thought it might be an insect blight, the bug eating so fast then passing stool that drops on the lower leaves which causes a fungal infection.  A tree 'chopper' suggested we trim them down to truck and spray as they grow.  Please could you give me some understanding of this disease and what course of action we should take ie: prune and treat or just take them out?   Thank you so much for your help.

Answer
Your pears have fire blight. This disease is caused by bacteria rather than fungi, so fungicides do not control it. A bactericide containing streptomycin sulphate (Agri-Mycin, etc) can be sprayed on trees at five day intervals when the blooms are open. This product is expensive and must be used during bloom time.

You抣l have to look hard for the streptomycin bactericide. Call your local Extension service office (1-800-ASKUGA-1) if you have difficulty finding it.

Another product, Serenade, is a bacteria that helps control fire blight. It too must be used at bloom time.

Since it requires specific environmental conditions to develop, the disease is wide-spread in some years but scarce in others. 態radford?flowering pear is actually moderately resistant to fire blight while 慉ristocrat?and 慍apital?are highly susceptible.

In your case, the damage has already been done and the right time to spray is past. Your best bet now is to use a pole pruner to remove the affected black twigs. This will be a two-person job because the blades of the pruner must be disinfected between each pruning cut. Mix a 1:9 solution of alcohol:water and pour it into an inexpensive spray bottle. As you work, remove each branch from the tree and lower the pruner so your partner can disinfect the blades.