Roots, Shoots, Fruits & Flowers: Tomato Zippering, Dog Vomit Slime Mold & Invasive Frustration

A closeup of a deformed tomato.

Tomato Zippering

Sumner, a vegetable gardener, sent a picture of an unusual tomato asked, “Can you identify my problem?”

This tomato has a condition called “zippering”. According to the Cornell University website, “This disorder (abiotic disease) happens when the flower anther sticks to the developing fruit as it grows. Characteristic symptom is a thin brown longitudinal scar with transverse scars resembling a zipper. It extends down the fruit. There may be more than one scar on a fruit. An open hole may develop next to the scar. Affected fruit remains solid and eatable; rot does not ensue.

Zippering is more likely to occur during cool weather. Some varieties are more prone to this disorder. The only option for controlling this disorder is to grow varieties not prone to zippering.”

58_fig_2_dog_vomit_slime_moldjpgSlime mold in a vegetable garden.

Dog Vomit Slime Mold

Chrissy emailed some pictures and asked, “Hey there Mr [AHA], I need help identifying this fungus that has suddenly pooped up in my cucumber garden. I sprayed with Neem oil a week or so ago. I have attached pictures. I hope this doesn't ruin the crop.”

Chrissy has “dog vomit slime mold” in her garden. Recently, Chris Dunaway, an Area Horticulture Agent in the New Orleans area, wrote about this strange life form, “Yet for having such an un-flattering name, dog vomit slime molds are fascinating and harmless creatures that provide a useful service. As they creep along, yes, they move, they ingulf and ingest bacteria, yeasts, spores, and decaying organic matter. In other words, they are natures cleaning crew. But because their favorite home is in decaying plant material and compost piles are made up of decaying plant material, these molds will frequently take up residence in our gardens. Do not worry because they are not harmful to the growing plants and in fact, their presence can be an indicator of low fertility in the garden. This is because unfinished compost has more of the wood digesting bacteria and fungi which are the slime mold’s primary food source. These fungi lock up essential nutrients, especially nitrogen, as they work to break down the cellulosic material. This is common in new gardens made with garden soil from dealers that add undigested wood chips to their mix. If you see dog vomit slime molds in your garden, fertilize with a water-soluble fertilizer that is readily available to the plants.”

Invasive Frustration

Sherry recently convey her frustration about harmful plants, “I’m confused about invasive species. I was on a website about invasive species and they listed a lot of plants that are sold in nurseries still today as ornamentals. Why are known invasive species still allowed to be sold in nurseries to non-suspecting people who do not know what they are buying? The government has all these programs to eradicate & report invasive species and yet they can be sold unceasingly. There are also a lot of agencies that have their own opinions of what is invasive and not all lists agree with each other.

It seems that there might not be an answer for all these discrepancies, but I thought I’d ask what you knew about it anyway.”

AHA replied, “Thank you for your question. Yes, the nursery trade is often the source of invasive plants in the landscapes. As I understand both federal and state agricultural agencies will designate a plant as ‘noxious’ and it should be prohibited from sales.

If an invasive plant is not ‘noxious’ then it is legal to sell. Not all invasive plants are deemed ‘noxious’ even though we know they are ecologically damaging.

I hope this answer is helpful. I agree with your premise that some of these plants should be unavailable to the public due to their invasiveness.”

If you want to contact Roots, Shoots, Fruits and Flowers, please send your questions and pictures to Keith Hawkins, Area Horticulture Agent (AHA), 337-463-7006 or Also, you can be on the “green thumbs” email list by emailing your request to the address above.

“This work has been supported, in part, by the USDA National Institute of Food and Agriculture, Renewable Resources Extension Act Award, Accession Number 1011417.”

5/7/2020 6:40:53 PM
Rate This Article:

Have a question or comment about the information on this page?

Innovate . Educate . Improve Lives

The LSU AgCenter and the LSU College of Agriculture