PROTECT TREES FROM POPLAR BORERS
Q I have a problem that I don’t think you have addressed previously. We have three mature columnar aspen trees in a very critical portion of your yard. Recently I have noticed sawdust around the base of the trees, as well as in the crotches of many of the tree branches. In addition, I see small streaks of sap running down one of the trees. I have noticed large black ants in our wood mulch as well. I believe the trees may be infected with a colony of carpenter ants or some type of borer. I would like to eliminate them before they do more damage. Your suggestions are welcomed.
A The problem is not with the ants, but it does sounds like the problem is a poplar borer, an insect that affects columnar aspen, poplar and willow trees. In late June, adult females cut notches into the bark, where they lay one or two eggs. The larvae then hatch and burrow into the bark for the rest of the summer and remain there for the winter. The following spring they enter the heartwood of the tree, where they feed for two years before maturing and exiting the tree.
The sap running down the tree and the sawdust are telltale signs that these insects have entered the tree. If you were to remove the bark in the area where the holes can be observed you would see the points of entry and where the eggs were laid. The insects usually like to burrow into the larger branches and into the main trunk down to the root collar.
Dealing with these insects becomes difficult once they have burrowed into the tree, but there are some possible solutions. Look for holes in the branches and trunk. They should be about a quarter-inch in diameter. You can try spraying affected trees with permethrin-based insecticides such as Ambush or Doktor Doom House and Garden. This will help to eliminate active adults prior to them laying eggs. Just spray the bore holes and surrounding areas of the tree.
Or, if you prefer to give something else a try, you can actually insert a fine gauge wire into the hole and keep poking it in and out, not unlike a plumber’s snake. You will eventually reach the borer if you have enough patience and can spear it with the wire, ending its munching days forever. I would certainly try this method, as you can likely save the tree on your own without using any insecticides.
Q I am curious about introducing ladybugs into my garden as pest control for an aphid problem I always seem to have, but am wondering if they will just fly away. Would I waste my money buying them?
A I know of some gardeners who have tried introducing ladybugs into their garden in the Edmonton area. Unfortunately it was not successful, because the ladybugs have a mind of their own and did not stay in the yard they were introduced to. When introducing ladybugs to the garden, the hope is that they will establish a colony in your yard and stay put. A single ladybug can eat 5,000 aphids in its lifetime, so if you can get them to form a colony the benefits are great. That is the ideal scenario, but the ladybugs don’t always follow protocol.
I can offer a couple of tips on how you can entice the ladybugs to stick around. Release them in late evening, and before you release them spray your plants’ leaves with water.
Are these tips foolproof ? No. In fact, I have a friend who recently released 2,000 ladybugs in her yard. Within a week the number was down to approximately 400, and in another week she could only find four ladybugs. Now, what about her aphids? She claims the aphid population dropped dramatically, so perhaps the ladybugs moved on because there was less to eat? Good luck and happy gardening!
Gerald Filipski is a member of the Garden Writers of America. He is the author of Just Ask Jerry. Email your questions to filipskigerald@gmail.com. To read previous columns, go to edmontonjournal.com/filipski