What is Happening to My Tomato Leaves

Last week there were a lot of questions about what is happening to my tomato leaves. To me, it seems that tomato diseases have become more prevalent due to warmer springs and longer dew times.

One is an early blight which was showing earlier this year. It looks like dark brown spots or blotches surrounded by a yellow color affecting older leaves gradually moving up the plant. If not treated this fungus knocks the plant down quickly. Treat with a garden fungicide to protect the non-affected leaves. Remove the affected leaves. There is a late blight that occurs later in the summer which is more virulent.

Septoria leaf spot is another fungus that looks like early blight. The dark spots are smaller and more round with yellow coloration between the spots. Again, a garden fungicide will protect the new leaves.

If your newer leaves are curling and becoming distorted, twisted, and curled now without any spots, it may be herbicide injury. It is common now with spraying weeds and using weed and feed products with 2,4-D or Dicamba in the product. On a warm, windy day, sprays with 2,4-D can vaporize and be carried by the wind for a long way. If the plant is not too badly damaged, it may outgrow this effect. If the plant is too badly damaged, it may be quicker to replant within a short day producing tomato plants. Never mulch with treated grass clippings until you have mowed at least 3 times.

Later on, there will be a leaf curl where the leaves curl upward making the plant look sick. This is a response to the foliage growing faster than the roots. Water uptake is insufficient, making the leaves curl upward to reduce transpiration. This condition will stop as the plant foliage catches up to the root growth. To reduce plant transpiration, keep even soil moisture and mulch to keep the soil cool. Heirloom tomatoes are more prone to this than hybrid tomatoes. Some areas call this summer blight, even though there is no disease cause.

To prevent or lessen the fungus, use crop rotation, grow the tomatoes at one end of the garden, and switch to the other end of the garden the following year. Remove all old plant debris from the area this fall. Most importantly, do not overhead water. This splashes the spores onto non-affected leaves. Use a drip form of irrigation. If you have to water overhead, water in the early morning. Remove affected leaves and discard. Use plastic or organic mulch on the soil to prevent the splashing of spores.

Use fungicides to prevent the new leaves from getting infected. An all-purpose garden fungicide will work making sure that blights and Septoria are listed on the product. Some types are Daconil, Serenade (which is a biological fungicide), Mancozeb Flowable (a fungicide with Zinc). Follow the directions and reapply every 10 days and after a rain.

Working in the Garden this Week

Crabgrass plant along sidewalk

If you are working in the garden this week, here are a few things to consider. Crabgrass is now germinating and growing. If you have a lot of this grass, use a post-emergent crabgrass killer as long as the plants are under a couple of inches in diameter. This grass shows up as a light green low-growing plant growing in areas with numerous plants.

Plum curculio

Ants on peony plants do not hurt the plants. They are eating the sap from the flowers and will go away after the plant has done blooming. If you have young apple trees or trees with apples on them, now is the time to spray apple scab (a fungus coming from juniper trees) is now with an all-purpose orchard spray. If you have some good-looking plums, the plum curculio is out eating holes in the fruit. You can use a pyrethrum or malathion spray.

Poorly pollinated yellow zucchini squash

Some people have early blossoms on summer squash (and soon with cucumbers) that do not set any fruit. For most vine crops the first flowers are male and will not set but later on, the female flowers come out and the plant will start producing. For little squash fruit rotting before getting big is caused by inadequate fertilization and they will grow out of this condition. I remove fruit if the plant is little thereby giving more energy to the parent plant’s growth.

If you have time, remove the spent lilac blossoms, they will produce more flowers next year. If any trees or shrubs have dead canes or limbs, remove them. Do not use any paint or black tar on the wound for this causes rot and decay because the air can not dry the area out.

Blossom end rot on tomatoes

Many use eggshells or tums around tomato plants to prevent blossom end rot on tomatoes or peppers. I found placing the plants in a mulch (plastic or organic) keeps the soil evenly moist and cool will help. Some varieties of tomatoes are more prone to this condition than others like early girl and the smaller cherry tomatoes. Epsom salts used heavily can harm the soil because it is a type of salt.

Things Happening this Week in the Landscape

Things happening this week in the landscape include the high number of moths flying around. There is not much you can do to eliminate them except for turning out any exterior lights and making sure there are no windows or doors open to your house at night. Also, pull the drape so the inside lights do not shine out for a couple of weeks. These moths will lay eggs which will hatch into the army cutworm. Hopefully, the garden and annual plants will be big enough to guard against this.

The cedar apple rust galls are showing up on the juniper trees now and will spread to the apple tree leaves. This will be the time to spray an all-purpose orchard spray on the tree leaves now, especially on young trees and older trees if they have a crop of young apples.

If you have a lawn grub problem, June is the time to apply grub control to the lawn. GrubX is a good granular product that can be scattered on the lawn by a fertilizer spreader. A higher mowing height and good lawn culture help prevent grub infestations. Dead areas in the lawn now are not caused by grubs but by winterkill.

Ticks are still a major problem especially if you go camping or areas of tall grass around your lawn. To prevent the little guys from crawling on you, use a product containing 30% Deet on your clothing. Higher Deet products do not mean they are better but will last longer. There is a 100% Deet product, however, it might be better to use a lower percentage and spray more often.

A lot of evergreens are showing winterkill on one side of the tree or shrub. See if new growth appears soon, if not, that area of the plant is dead.