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Why Are My Tomato Leaves Curling?

Upward curling tomato leave indicates stress more often than disease.

“Lots of my tomato plants have curling upward leaves, and in most cases only edge damage. Why?” Questions from James of Greenville, South Carolina

Answer: There is a Tomato Yellow Leaf Curl Virus, but your plant lacks several of the symptoms, including stunting, yellowing, and eventual leaf browning. Tomato plants more commonly experience physiological leaf curl when subjected to various environmental stresses. In this case, I believe yours is caused by environmental stress.  Here are four possible sources of stress.

Environmental Tomato Leaf Curl Causes

  1. Too little or too much water — Vines fail to grow as well when water is lacking, and they develop root rot when there is too much water. Either can cause leaf curl. Regular, even watering will yield the best results.
  2. High heat — Temperatures over 85 degrees F will cause most tomato plants stress and sometimes leaf curl. Some tomatoes are more heat-tolerant. Two of the best heat-tolerant varieties include the large, red-fruited ‘Heatmaster‘, which can take the high heat of the South, and disease and heat-resistant ‘Heatwave II‘, which bears deep red tomatoes with good flavor.
  3. Wind stress — High winds cause rapid water loss from the leaves and stresses vines. Leaf curl can result.
  4. Herbicide damage – Glyphosate herbicide damage is most common. It can cause this type of leaf appearance if a small amount reached your tomatoes from a downwind application.

Could any possibilities be the cause? Please let me know. In the interim, click here to read more about leaf curl, and watch the video below about growing tomatoes to perfection!

Happy gardening!

Jessie Keith

Black Gold Horticulturist

What Is Causing My Grape Leaves to Look Distorted?

“I have a St.Theresa grapevine that has grown and produced very well. After being devastated by Japanese beetles last year, it developed several distorted leaves. Is it possible the Japanese beetles gave it some virus or disease? I cut it way back. Now, this spring, it has been making a comeback. But I noticed yesterday that some of the leaves at the ends of the new growth look distorted and discolored again. They look like the pictures of Eutypa Dieback. Help! What do I do?” Sharon of Colorado

Answer: Japanese Beetles (Popillia japonica) have been reported to vector some bean viruses, but there is no report or research to support that they spread any diseases of grape (Vitis vinifera). What is more likely is that your vines were weakened by the damage, left more prone to infection, and they obtained a disease. Other grape pests, such as mites, also spread grape diseases and they could have been the vestors. Either way, there are several grape diseases that can cause leaf distortion and discoloration. Here are some possible foliar grape diseases along with identification tips and management suggestions.

Grape Foliar Diseases That Cause Distortion

  1. Grape Anthracnose (Elsinoe ampelina, fungal) causes symptoms on both leaves and fruit. Foliage will appear spotted and have brown lesions that cause leaves to curl. The grapes also develop dark lesions. Apply a Bordeaux mixture spray or Liquid Copper Fungicide to infected vines when they are dormant.
  2. Eutypa dieback (Eutypa lata, fungal disease): Leaves can appear stunted, curled, and cupped. It is easily identified by cutting a stem: infected wood will have a wedge of darker, discolored wood against healthy, lighter wood. It infects older vines that are over five years of age. There is no known cure, so infected vines must be removed.
  3. Viral Diseases: There are many viral diseases of the grape that cause leaf distortions. (Click here for a visual guide of grape viral diseases.) All are incurable, so I recommend removing any vines that you are certain are infected with a viral infection.

Getting outside help is my ultimate recommendation. The best way to firmly identify your grape disease is to send a sample to your local extension agent and have it tested in a lab. (Please click here to search for your local extension agent!) Definitive results are necessary because you do not want to destroy your grape if it has a curable disease.

I hope that these tips help!

Happy gardening,

Jessie Keith

Black Gold Horticulturist

 

Leafy Holly for Holiday Clipping

Holly BerriesAfter the leaves fall, hollies stand out all over your neighborhood with their bright red fruit. The holly is a locally proven species making it the best choice for planting in your garden too. Hollies prefer well drained acidic soil, so amend your planting soil with Black Gold Peat Moss Plus. If you already have hollies growing in your landscape, use fertilizer formulated for acid-loving plants.