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Posts Tagged ‘herbicide damage to tomatoes’

Sad looking tomato plants

I'm pretty sure these Rutgers tomatoes are supposed to be bigger than 2" in diameter!

I’m pretty sure these Rutgers
tomatoes are supposed to be
larger than 2″ in diameter!

My tomatoes are a disaster this year!

Their growth is slow and they are not producing many flowers or fruit. Plus, the fruit that has formed is way smaller than it should be. It’s very disappointing!

I planted about 40 plants which included 9 different varieties, most of which are heirlooms because they are so delicious. Normally by this time of the season, the plants would be lush and full and looming over the top of our 6 foot trellises. There would also be lots of beautiful full-sized tomatoes with many more coming on. Not so this year!

The season started out on a downside when, within a few days of planting out my transplants, we noticed some severe cupping and curling of the foliage especially on the youngest leaves. When I saw it I immediately thought – classic 2,4-D herbicide injury! I wish I had taken some pictures of the damage.

Tomato injury caused by 2,4-D

Tomato injury caused by 2,4-D

It affected all of the tomato plants. I also noticed 2,4-D injury on our grape vines which are growing on the hill above the vegetable garden. Tomatoes and grapes are especially sensitive to broadleaf herbicides. Even light exposures can result in injury to the plants. If an herbicide like glyphosate (Roundup) or one that contains 2,4-D or dicamba is applied in the vicinity of a vegetable garden, it can easily drift onto the plants. Herbicides can drift pretty far if caught by the wind! We hadn’t sprayed anything but we found out later that a neighbor had been spraying a product containing 2,4-D to control thistle in the field right beside our vegetable garden. The spray must have drifted onto our newly planted tomatoes.

Strike One!

 

The spindly vines have a lot of diseased foliage.

The spindly vines have a lot
of diseased foliage.

We planted our tomatoes and most of the rest of the garden on the 21st of May. June had higher than normal rainfall, often in the form of heavy thunderstorms. This wet weather led to disease problems, especially in our heirloom varieties which make up about 80 percent of what we grow. We always have some disease in our tomatoes that wipes out their lower branches but it never seems to affect their production much. This year it was much worse. I am pretty convinced that the herbicide injury weakened and stressed the plants and left them more susceptible to fungal diseases.

Strike Two!

 

Hornworm damage on the Better Boy tomatoes

Hornworm damage on these
small ‘Better Boy’ tomatoes

Though we never seem to have much insect damage on our tomatoes, we have had an occasional hornworm on the plants. So far this year, Eric has discovered two hornworms on the tomatoes but only after they had almost completely defoliated a couple of the plants and chewed a few of the tomatoes as well! They are well camouflaged and it took a bit of hunting before he found and squashed the two culprits. Hopefully there aren’t more lurking among the foliage.

Strike Three!

 

With all these strikes against them, the plants have suffered tremendously. The foliage is sparse and the stems are elongated and spindly. I think this is mainly due to the herbicide injury early in the season.

The 'Pruden's Purple' tomato on the right is deformed and cat faced but at least it is larger.

The ‘Pruden’s Purple’ tomatoes
are small and some are deformed.

Though the plants have slowly outgrown the damage and the new growth is fairly normal, the plants are stunted and few flowers are being formed. The fruit that has formed is mostly remaining very small. I harvested a few medium-sized ‘Cherokee Purple’ tomatoes but most were deformed with severe cat facing (another symptom of 2,4-D injury).

Some of the problem may be environmental, too. I have heard that other people are having similar issues with their tomatoes; slow growth and the production of very few tomatoes that are all small in size. It may just be a bad year for growing tomatoes!

Unfortunately, it doesn’t look like we will be harvesting very many tomatoes this year. We should have enough to enjoy fresh but I’m pretty sure we won’t get enough to can.

The pole beans are doing very well!

The pole beans are doing very well!

On the bright side, the pole beans are doing very well except for 2 or 3 poles where some critter has nipped off the lower leaves. The vines are still strong and producing lots of beans at the top. We planted Rattlesnake beans, a purple pole bean, and a new one for us – Lazy Housewife Pole Beans. Yum!

The cucumbers have also produced well this year. So far I’ve made 23 pints of my famous bread and butter pickles and still have plenty to slice up for my lunches and I’ve even given a bunch away! I’ll be making more pickles this weekend and freezing beans, too!

I’m just so sad about my tomatoes …

Until next time –
Here’s hoping your tomatoes are doing better than mine!

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Tomato harvest

Well, it’s that time of the year! The tomato questions are pouring in on our discussion board, Andre’s radio show, and over the phone and e-mails. At this point, the questions are mostly concerning problems with the foliage and just a few about the fruit.

One of the most recent discussion board posts brought up an issue that many gardeners may not be aware of …

“I have six different varieties of tomato plants planted in my raised bed. I noticed last week that the leaves had curled upwards. This week I noticed now that the leaves appear to be a little wilted as well as the blooms. The growth also seems somewhat stunted …

There are several things that can cause tomato leaves to curl but this combination of symptoms seemed consistent with herbicide injury.

Tomato injury caused by 2,4-D

Tomato injury caused by 2,4-D exposure

Herbicide drift can be a major problem for tomatoes because they are very sensitive to broadleaf herbicides. Even light exposures can result in injury to the plants. If an herbicide like glyphosate (Roundup) or a product containing 2,4-D or dicamba is applied in the vicinity of a vegetable garden, it can easily drift onto the plants. Herbicides can drift quite far when caught by the wind!

If they are exposed to only small amounts, the plants will usually survive and eventually outgrow the damage. Heavier exposures can be lethal.

Drift is not the only way that tomatoes can be exposed to herbicides.

  • If you spray your tomatoes with a fungicide or insecticide using a sprayer that has also been used to spray an herbicide, there may be herbicide residue left in the tank.
  • Herbicide damage can also occur if tomatoes are mulched with grass clippings from a lawn that has been treated with a weed and feed product or a broad leaf weed killer.
  • Lately, there have even been problems with plant damage resulting from mulches and compost that have been made from hay or manure taken from fields that had been sprayed with the herbicide Grazon.
Characteristic symptoms of glyphosate injury - yellowing at base of leaflets

Telltale symptoms of glyphosate injury –
yellowing at base of leaflets

In this case, as I learned from a later post, it turns out that a neighbor had been spraying herbicides in his yard and the drift had hit the tomato patch. Hopefully over time the plants will recover but flowering and fruit production may be delayed.

The bottom line:

  • Never spray herbicides in windy or breezy conditions
  • Use separate sprayers for herbicides and pesticides
  • Don’t mulch your vegetable garden with grass clippings if you have treated your lawn with a broadleaf herbicide

What else can cause tomato leaves to curl?

Physiological leaf roll is due to environmental stress factors

Physiological leaf roll is due to
environmental stress factors

Curled or rolled leaves can also be a physiological response by the plant to adverse weather conditions; too hot, too dry, too wet, too windy. The overall growth of the plant is usually not affected and the symptoms normally disappear when conditions improve.

Be careful not to over-water tomatoes. Overly wet soil conditions are often to blame for leaf roll.

Mulching your tomatoes will help maintain more even moisture content in the soil and also helps to maintain a more constant soil temperature.

There are several viral diseases such as curly top, yellow leaf curl, and mosaic virus that can cause curling of leaves, as well as stunted growth and pale leaves. There is no cure for these diseases and the plants cannot be saved.

Tomatoes with yellowing foliage and brown patches

Fungal disease is responsible for the majority of the tomato problems we face.

Fungal disease is responsible for the
majority of the tomato problems we face.

Some of the most common tomato problems are caused by fungal diseases. The tomato blights (early blight and late blight), as well as some of the wilt diseases and leaf spot diseases can be devastating to tomato crops. The first symptom is normally the yellowing of the older, lower leaves and branches.

Fungal spores that cause these diseases are found in the soil and on plant debris left in the garden. It is very important to rake up and remove old plants, fallen leaves, and rotting fruit from the garden at the end of the season. This important “housekeeping” task will help to reduce the incidence of fungal disease in the following season.

Mulching around your vegetable plants is another great way to reduce disease. This keeps soil (which may be filled with fungal spores) from splashing up onto the stems and leaves of your vegetable plants. Mulching the vegetable garden has so many benefits that it is worth doing every year!

If your tomatoes are showing signs of disease, prune off the diseased branches and throw them in the trash (do not compost them).

To prevent the disease from spreading to healthy foliage, spray the plants with a fungicide that is listed for use on edibles (Bonide Copper Fungicide, Mancozeb, or Fung-onil). Sometimes it’s good to alternate different fungicides.

Always read and follow the label directions!

Here are a few more tips to help you avoid (or deal with) tomato problems this season. Here’s to a great harvest!

Until next time – Happy Gardening!

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