Question
My plum trees are infected with larvae under their barks, making them ooze sticky liquid. I have just used Bayer fruit tree insect control around the base. But I want to know about nematodes that I could use to combat the problem.

Answer
There is a newer systemic insecticide called Merit that works well on borers. It is sprayed on the wound are and adjacent trunk and is absorbed into the bark and wood killing the insect. I would spray now and again in 30 days. If you still see fresh signs of insect activity spray a third time but I feel the two sprays will solve the problem.

American plum borers tend to attack trees that are weakened either by wounds to the trunk or under stress. I would recommend that the tree be fertilized with 10-10-10  fertilizer at the rate of 1 lb of fertilizer per inch of trunk diameter scattered around the tree under the foliage line and watered in good. Do this now and again in early fall. This will strengthen the trees root system and increase the overall health of the tree.

Here is the information on the nematodes.

Use Parasitic Nematodes

Step 1
Purchase Steinemema carpocapsae nematodes, which will actively attack and kill peach tree borer larvae, from a reputable resource. Mix the nematodes with distilled water at the rate of 1 million worms to to one ounce of water. Place the mixture into a squeeze bottle with a long piece of plastic tubing attached.

Step 2
Inspect the trunk for peach tree borer activity. Look for holes that have sawdust-like frass at their entrances. Insert the tubing into these holes created by the borers. Inject the liquid mixture into each hole until it flows out of the hole. Mark the holes for future inspection.

Step 3
Examine the holes one week later, to see if more frass is visible. If so, retreat with more nematodes.

Step 4
Store the nematodes in a cool dry place. Ensure the nematodes are not exposed to sunlight, as this will kill them.



Here is a source for these nematodes I am sure there are other sources--check with your local garden type/nursery store. http://www.arbico-organics.com/product/nematodes-sc-backyard/