It's time Donna. Time to let loose the nematodes

Each week, Susan Richards of New North Greenhouses answers your gardening questions. Have questions about your gardening needs? Please email her at [email protected]

Mark: I have been having a problem with cucumber beetles destroying my cucumber and zucchini plants for the past few years.  Prior to that I have never seen them in my garden.

Do you have any ideas for how to deal with these cucumber beetles and stop them from destroying my plants?

The best non-toxic solution for cucumber beetle in the vegetable garden is to set out a lure and trap. This one should do the job for you. 

Dan: I have an apple tree that seems to not want to grow many good leaves this year.

We have two young apple trees planted about 3 years ago, they are supposed to have several varieties grafted onto them, so each branch gives a different kind of apple.

Most years one seems more healthy than the other, but this year, one looks alarmingly weak. Some branches seem to have nothing coming, while the ones that do have leaves, has small leaves.

Should we be worried about the tree? Is there anything we can do to help it?

Your tree may have non-hardy apple varieties as some of the grafts. This past winter was extremely tough on numerous trees and shrubs. Ones that aren't hardy to our area or just borderlines, suffered the most.

Unfortunately there is nothing you can do about this particular problem. You might have to replace the tree with one hardy to our area.

Marg: My magnolia had many buds but they didn’t open. There is white fungus-like growth on the branches. What could be the problem?

The past cold winter may have killed the flower buds of your magnolia. It was unusually harsh. If they don't open by the end of June, unfortunately they won't.

The lichen on the branches is totally non-harmful but can be more prevalent on plants lacking vigor. It may be a sign that your magnolia has been weakened by a series of colder than normal winters. You could use fertilizer spikes to give it some nutrients.

Donna: Should I be applying nematodes to control white grubs in my lawn both spring and fall?

Yes, although the fall application is the most important, any grubs that weren't killed then are feeding voraciously on grass and plant roots now. Soon they will pupate and eventually emerge as beetles. The beetles will lay eggs that hatch in late August, starting the whole cycle over again!

By applying beneficial nematodes twice per season, you will eventually reduce the population of these harmful pests.