This week's garden questions, Vegetable and Fruits

Tomato Problems

Most of the questions that will be coming in will relate to tomato problems, and earlier this summer, relate to tomato problems.

Septoria Leaf Spot

As in most years, the most frequent problem with tomatoes this year will be leaf spot and blight being so humid and hot along with the rain recently. There are several common fungal blights with Septoria leaf spot being the most common. It causes small dark spots on the leaves then the leaves tend to turn yellow and fall off. It usually starts at the bottom of the plant and works its way upwards. If you water your garden with overhead sprinklers, that can spread it too. This disease usually does not cause damage to the fruit, but the plant loses so many leaves that it cannot support a good crop of fruit and the remaining fruit can get sunscald.

Early Blight
Late Blight

The other two main diseases of tomatoes are late blight and early blight. They cause larger, blotchy spots to develop on the leaves and fruit. Early blight can happen now with late blight later in August. All three of these diseases can be controlled with a preventive fungicide spray especially when you start to see the early signs. Use an all-purpose garden fungicide Daconil.

Not common in our area are bacterial spot and bacterial speck. These bacterial diseases cause small dark spots to develop on the fruit and leaves. The spots are usually surrounded by a yellow halo at the initial stages of the disease. Unlike fungal diseases, fungicides are of little use in controlling bacterial disease problems.

Since I have mulch around the plants with plastic mulch, the problem has been reduced. Spacing plants apart and staking to allow for good air circulation is also helpful. Using tomato cages around plants can help too. Unfortunately, most of the inexpensive tomato cages that are sold are simply not that strong and usually collapse under the weight of a large plant in a windstorm, so I pound a tee post into the ground and tie it to the cage. A stronger cage or other support is more helpful. Using drip tube irrigation helps control foliage diseases by keeping them dry without having to overhead water.

House pests

Dog Ticks Around the House

This week there are questions about how to rid dog ticks around the house. Good question. Dog ticks survive in tall grassy areas with shade because they like humid, sheltered locations waiting for some animal to pick them up.

The easiest way to reduce the number of ticks is to keep the grass cut, especially under trees and shrubs. There is less population of ticks on a well-groomed lawn than on a weedy lawn. The broad leaf weeds provide more shade.

If you have overgrown shrubs, next spring prune them to open them to sunlight. It will be good for the health of the shrubs and hedges. Remove any trashy areas in the backyard.

If you wish to spray with a chemical, do it in the evening. We do not want to be killing beneficial insects like honeybees. Spray especially the brushy areas, along the perimeter of the lawn especially in the country, and groundcovers. Permectrin sprays are good as a repellent for the lawn.

One organic control is a spray with Metarhizium brunneum, which is a fungus found in the soils being effective in reducing tick populations. You would have to order this from a nursery catalog or online. According to consumer reports, the Wondercide yard spray with Natural Oils works as a treatment and repellent which is safe for pets and people.

Shade Trees and Shrubs

Native Tree to South Dakota

Do you have a hard time getting trees to grow because of your location where you want a tree? Try a native tree to South Dakota recommended by SDSU.

Boxelder Tree

My favorite is the boxelder tree. Now before you yell at me, it is only the female tree that attracts the boxelder bugs. You can buy male trees which do not attract bugs. Boxelder is a soft-wood maple with a 45-foot, rounded growth habit. They take a little more water when young but become drought tolerant later on. There is a “Sensation” variety with yellowish foliage.

American Linden

American linden is a stately shade tree growing 60 feet in height. It has white drooping flower clusters. This tree has many cultivated varieties.

Kentucky coffee tree

Kentucky coffee tree grows to 50 feet tall. The leaves resemble the leaves of a honeylocust only much larger. The seeds are nutlike clusters that were used by early Americans as a coffee substitute. There used to be a coffee tree in the Winner Park years ago.

Hackberry tree

Hackberry trees a tough, drought-resistant, and pH tolerant making them a great choice for a shade tree. The leaves often get nipple gall, which are small bumps on the leaves but do not harm the tree.

Honeylocust

Honeylocust creates a light shade for people that do not want a dense shade in their yards. This tree has many cultivars like “Shademaster” (larger leaves than the typical honeylocust), “Skyline” (ferny leaf appearance), and “Sunburst” (with yellowish foliage), etc. Newer varieties do not get the pods or thorns.

Black walnut tree

Black walnut is grown mainly for its wood in the furniture business. The tree needs room to grow to 100 feet tall. The leaves are compound divided growing over a foot long. Walnut roots produce a growth-inhibiting chemical that keeps other trees and plants from growing beneath them. Bluegrass will grow beneath the light shade of the tree.

The black locust, not related to the honeylocust, is a smaller shade tree around 50 feet high. It has beautiful drooping, fragrant flowers of pink to red in the spring.