In the Gardens this Week

There have been some questions in the gardens this week about strawberries turning black and shriveling (grey mold). This is a fungus called Botrytis which affects fruits, flowers, and sometimes leaves. It is worse in cooler, wetter weather also affecting roses and marigolds or other flowers and other fruits. Fungicide like Daconil helps prevent the fungus from spreading and affecting new buds and fruits. Also increasing air flow helps by thinning or increasing spacing.

If you have hackberry trees, you will notice bumps underneath the leaves. This is from a little fly (midge) that lays an egg, and the portion of the leaf grows around the newly hatched insect protecting it until it emerges. Since the tree and insect are both native, all hackberry trees will get this condition depending on the weather which does not harm the tree. I live with it.

Hackberry Galls

Be on the outlook for squash borers. The adult lays eggs around the base of the plants. These hatch and the tiny grubs burrow into the vine causing wilting. Tests show that aluminum foil around the stems where they come out of the ground confuses the borers when they hatch. Also, a Malathion spray around the ground kills the insect.

Adult Squash Borer

It is a good idea to tour your garden or flowerbed every day scouting for disease and insects. Please keep a look out for cucumber beetles, cabbage worms, and potato beetles.

The weeds of the week are the foxtail barley (neither a foxtail nor barley) and downy brome grass (cheatgrass) not to be confused with the perennial smooth bromegrass. The plants are easy to pull out in the flowerbed or garden. In the lawns, do not let them set seed. A good stand of sod will crowd these weeds out.

Winterkill on Alberta Spruce

I have noticed that many Alberta Spruce get winterkilled. The dead will not grow back and if the whole side or top of the plant is dead, replant with another hardier plant.

Stop harvesting asparagus when the spears get to the diameter of a pencil. Let the spears grow until a hard frost for next year’s crop.

Common Issues in Gardens this Week

Let’s have a chat about some common issues in gardens this week and how to tackle them!

First off, if you’re growing cucumbers, there are two diseases you should be on the lookout for anthracnose and wilt. Anthracnose is a fungal disease that causes irregular spots on cucumber leaves. If you’ve had problems with this in the past, it’s a good idea to spray your plants with a garden fungicide to keep the leaves healthy.

Cucumber wilt is another nasty issue. It’s caused by bacteria carried by striped or spotted cucumber beetles. This bacterium clogs the plant’s water tubes, leading to sudden wilting and eventually killing the plant. As soon as you spot these beetles, it’s time to spray them with Sevin or a similar insecticide. Also, remove any wilted plants to prevent the disease from spreading.

For those of you growing hollyhocks, you might see brownish or reddish spots on the leaves. This is a sign of rust, a fungal disease. Unfortunately, once you see these spots, it’s too late to treat the plant, but it will still bloom. To prevent rust, spray with a fungicide in late May and make sure to clean up plant debris in the fall.

This year, you might notice a lot of frost cracks in trees due to the unusual winter we had. These cracks happen because warm temperatures in February allowed the sap to flow, which then froze and caused the cells to explode, creating vertical cracks. There’s not much you can do except wait and see if the cracks heal themselves. Trees with smooth bark, like young red maples, are particularly prone to this. Just remove any dead bark to let air circulate around the wound.

If you’re dealing with little grasshoppers in your garden, especially in rural areas, try keeping the area around your garden mowed short as a barrier. If grasshoppers become a bigger problem, using bait can sometimes help.

On a different note, I recently gave my dog, Magdelin, a Bravecto chewable for ticks, and within three days, I didn’t find any more ticks on her. There are three types of ticks in South Dakota to be aware of. The most common is the dog tick, which can carry tularemia. Then there’s the Lone Star tick, which can carry various diseases, including Alpha-gal syndrome, making you allergic to red meat, and tularemia. Lastly, the Black-legged tick (deer tick) is known for carrying Lyme disease. If you spot Lone Star or Black-legged ticks, you can participate in South Dakota’s tick survey to help track their progression. You can find more information on the survey at the South Dakota Department of Health’s website: Tick Identification | South Dakota Department of Health (sd.gov).

Aphids Coming to Play this Week

Aphids are coming to play this week. These are tiny, mostly green soft-bodied insects sucking out the plant juices. Many aphids are only plant-specific to the plant family they attack. Like rose aphids attack only plants in the rose family. There are a few aphids that will attack a wide range of plants. As they suck out the plant juices the leaves will curl and wrap around them offering some protection. To treat for aphids, use high force sprayer attachment on a hose to knock off the insects and do this several times a week. You can also use Neem oil or insecticide soap.

People have been having various problems with roses. The main problem is because of our wetter weather, is black spot. This is a fungus causing black spots on the leaves often killing the leaf. Use a fungicide to protect new or unaffected leaves. There are varieties less susceptible to this fungus.

Another disease on rose not as common is virus complex. This encompasses three different viruses. Most likely they will not kill the rose but will make the leaf unattractive. No roses are immune to the virus which is transmitted by insects. It is best to remove the affected plant.

Lastly, if your rose leaves have round holes removed along the edge of the leaf, you have carpenter ants or bees. I would just let them be because they will not cause any harm.