Master Gardener Sue Morris: Check Your Apple Trees, Think Perennial Fertilization – West Central Tribune

With the abundance of rain this year, be on the lookout for powdery mildew. Powdery mildew can be a devastating disease for large garden phlox. It appears as disfiguring, powdery white spots on the foliage. When these spots coalesce, they can nearly obliterate any remaining green tissue, moving to the flowers as well.

Maintaining good air circulation will help reduce powdery mildew problems, but the best way to avoid the disease is to choose disease-resistant cultivars in the first place and then make sure they are not crowded or shaded when you plant them.

If necessary, you can begin a fungicide spray program using sulfur or chlorothalonil (sold as Daconil 2787) at the first sign of infection. Phlox may also develop other fungal spots on the leaves, especially on the lower leaves. However, these are rarely severe enough to warrant treatment.

There seems to be a bumper crop of thistles this year all over the state. Thistles where they have never grown before. This is the time of year when they start to bloom, so be vigilant to prevent that from happening so the seeds don’t blow away.

Maybe those of you who live in the city don’t have this problem, but we’ve really been flooded here in the country. Plus, the burn grass is abundant in places we’ve never seen it before.

I don’t know if this is the “right” name, but it can definitely burn your skin if you come into contact with it. Wash it off immediately with soap and water.

I hope you are keeping a close eye on your apple trees. This is a year of bountiful harvest on all my apple trees.

Don’t worry if you see apples falling from your trees this time of year. This is nature’s way of thinning out the crop to allow the remaining apples to grow larger.

Now is the time to remove some of the small fruits. As a general rule, there should be a fist-width gap between each apple.

As a reminder, do not pull the apples from the tree, but rather lift and twist them. This way, you will not disturb the spur that will become next year’s apple. Continue to pick up fallen fruit and keep the ground clean under the trees.

Watch for apple maggots. These insects tunnel into apples, leaving brown marks inside deformed apples that do not store well. Apple maggots emerge around July 1.

Spraying at intervals of 10 to 14 days with diazinon or Sevin is quite effective. Read and follow the instructions on the container carefully. If it does not rain, you can extend the time between sprays.

This is a great time to fertilize perennials. This should be stopped after August 1st to give the plants time to slow down and start preparing for winter (even we’re not ready for THAT). You can continue to fertilize your pots and annuals right up until frost if you wish.

If you grow squash, pumpkins, cucumbers or melons, you need to watch out for squash vine borers. The larvae bore holes into the stems, causing the plants to wilt and die.

The best way to control these insects is to treat them at the right time, when the adults are active and laying their eggs. These insects are moths that fly during the day and look like wasps. They are about 1/2 inch long and have an orange abdomen with black spots.

To detect them, watch for them in flight while you are in your garden or place yellow containers half filled with soapy water. They are attracted to the yellow and will fall into the containers and you can then check for them.

As soon as you see one, start treatment. As always, follow the instructions on the insecticide container.

Sue Morris, a gardening expert, has been writing a column for Kandiyohi County newspapers since 1991. She has been certified by the University of Minnesota as a gardening and horticulture expert since 1983. She lives in Kandiyohi County.