Garden almanac

This Week in the Garden for Aug 15th

Shippy Realty & Auction Blog potato beetle and larvae on potato leaf

This week in the garden the Colorado potato beetle showed up. These are reddish-orange fleshy larvae turning into the striped beetle adult. It does not take them long to decimate a potato plant. They are later this year so if your plants are maturing just pick them off. If you have a lot of plants that are still green, use Sevin insecticide.

Shippy Realty & Auction Blog fall webworms on an apple tree

Fall webworms are also showing up with their webs in fruit trees and cottonwoods. If you can reach them just pull out the web with the clump of caterpillars. They do not cause much damage this time of year compared to the tent caterpillars in the spring. A female moth lays her eggs and when they hatch, the worms spins this web to protect them from the elements and predators. You do want to control these insects on younger trees before they defoliate the leaves.

Shippy Realty & Auction Blog tomato skin crackling due to increase moisture.

Tomato skin splitting is a problem, however, there is not much you can you to prevent this. When the tomato gets ripe, its skin is no longer elastic. Then we get rain and the skin splits when the insides swell. Some varieties are more susceptible to this condition like cherry tomatoes. A mulch of straw or hay helps.

I had a question about how to tell if the apple is ripe. Lift up at the base of the fruit and if it breaks at the stem, it is ripe.

It is also the time to plant a newly seeded lawn or overseed an existing one because it is cooler than late spring requiring less constant moisture and weed stress is reduced. If you buy a bag of grass seed, it should have a tag on it stating the percentage of grass types and the amount of inert or other materials. The most common is a white tag, however, if it has a blue tag, that means it is certified by testing which is better.

Shippy Realty & Auction Blog pods on a honey locust tree

This is a great time to plant a tree or shrub up to 6 weeks before the soil freezes. The late summer or early fall is cooler, requiring less water and less stress for the tree. If you want a hardy tree, try honey locust. The new varieties do not have the pods. The old honey locust trees with pods planted in the shelterbelts were used as cattle feed in the past. During WWII, the pods were also used for making beer during the rationing.

If you do not mind experimenting and want to try something new in varieties of trees, try growing Turkish filbert, amur cork tree, northern pecan, bald cypress, American sycamore, or yellowwood. Our zone 4 is these trees limit, I have seen them in Pierre, SD. Try at your own risk! They may be easier to grow than our pH-limiting trees like red maple and oaks.

Garden Pests

Powdery Mildew

Last week I mentioned powdery mildew which was on point since quite a few people brought in and sent pictures of this fungus. Let’s go into a little more depth about this topic. The fungus gets into the leaf tissue and sends up fruiting structures which look like talcum powder on the leaves. This disease is plant specific meaning that the powdery mildew on the lilacs does not infect garden vegetables. Powdery mildew on phlox will not spread to other flowers.

Powdery Mildew on lilacs

If you find this talcum-like fungus on trees and shrubs do not worry this late in the season. It will not harm these woody plants except for ever-blooming roses. If it is on cucumbers and they are still in their prime bearing mode or winter and summer squash, I recommend treating these plants.

Powdery Mildew on a squash leaf

Use a garden fungicide like Daconil or a sulfur-based fungicide if you can find it to protect the leaves that are not infected. Sulfur is good because it is volatile and will get underneath the leaves. Some horticultural oils and even a 10% milk solution help coat the leaves protecting them from infection. Even washing the leaves helps reduce the spore amount. For roses and flowers, I would use a garden fungicide this late in the season to protect the unaffected leaves.

Some squash leaves have a natural variation of mottled light green of their leaves. This is natural and not a disease.

Powdery Mildew on a rose bush

Powdery mildew has not been a problem for the last couple of years because it was hotter and dryer. This year is different with the rainfall and cooler night temperatures which is the perfect conditions for spreading the disease.

Garden almanac, Garden Pests

This Week in the Garden (August 6th)

Powdery mildew fungus on a squash leaf.

This week in the garden, let’s start with powdery mildew that is starting to affect certain plants like squash vines. It looks like talcum powder sprinkled on the leaves. This fungus can attack most plants, especially lilacs, but rarely does any damage and shrubs or trees. I do use a fungicide like Daconil on my vining vegetable this time of year with another application after any rains to prevent infestations on summer and winter squash.

Blister beetles.

People in the country have noticed black or dark grey beetles eating certain flowers and vegetables. These are blister beetles usually coming from grazing land or alfalfa fields after being cut. They get their name from a secretion that will cause blisters if crushed or handled. Rarely do they cause much damage.

Tomato hornworm on a tomato plant.

The insect that will cause damage is the tomato hornworm. You may go out to your tomatoes and find a lot of the leaves that have been eaten. Look closely and you will find a green caterpillar the size of your pinky finger. It is easiest to pick them off the plant. These caterpillars will pupate into the large sphinx moth you see fluttering around now on the flowers.

Hedge balls in a bushel basket in a grocery store.

I have seen hedge balls being sold the last time in Pierre. They are the large non-edible fruit from the Osage orange tree. The wood was made into bows and baseball bats. The tree has been used around orchards as a trained hedge to eat critters away. Now the oil in the seeds is used in cosmetics. People use them for spider control in homes claiming they repel spiders and cockroaches away. SDSU rather busted this myth. While some oils in the fruit can act as a repellant, they had to extract and concentrate those oils to have any benefit. Using a border insecticide long-lasting spray around the home like Home Defense Spray will do much more in repelling insects.

Aster yellows affecting a white coneflower..

Aster yellows have been showing up in my asters this year. The first time I tried annual asters and ended up with only 50% of a crop. This is a bacteria spread by mainly leaf hoppers. This bacterium can also infect calendula, petunia, zinnia, mum, cosmos, marigold, coneflower, and other flowers. The symptoms are a stunted plant with brown edges on the leaves and odd-looking flowers. The only remedy is to remove the plant immediately to prevent the infection from going to other plants.

Keep deadheading (flower removal) of your flowerbed and containers. This keeps the flowers producing through the heat of summer into fall. I am deadheading calendulas and Mexican sunflowers every other day, fortunately, I planted just of few of these plants. Zinnia, cosmos, and marigold need weekly deadheading.

This is the time to prepare your soil to plant a lawn into. Spray the area with Roundup to kill everything. Rototill and smooth the ground and plant the grass seed. For shady areas buy a grass mix with fine fescue seed.