I thought the marigold plant was resistant to pests and diseases. But I found out the hard way that there are still some critters that can eat parts of this plant.
Marigold plant is being eaten by slugs, snails, aphids, spider mites, thrips, Japanese beetles. Animals such as rabbits, squirrels, deer, mice and birds also enjoy eating marigolds. Some pests and diseases like verticillum wilt, Botrytis blight may attack marigolds.
If your marigolds are being eaten, don’t worry. You can use plenty of methods to figure out what is the cause of the problem and get rid of it.
Insects
One of the most common reasons your marigolds are being eaten is insects. Here are some of the most common ones causing this problem.
1. Slugs and snails
The most common reason your marigold leaves and petals may be eaten could be slugs and snails. These pests enjoy the plant and are attracted to it.
These pests are nocturnal so you won’t see them on the marigold plant during the day. If you see trails of slime near the plant that’s a sign of slugs and snails visiting it. Another indicator of these pests is if the leaves have been chewed haphazardly.
You can visit the plants at night with a flashlight to confirm that slugs and snails are attacking the leaves and flowers.
The simplest method to get rid of them is to pick them by hand and drop them in a bucket of soapy water. You can also sprinkle salt on the slugs and snails to kill them. But you need to be careful not to put too much salt on the plant as it can damage them as well.
The slugs and snails are attracted to fermented foods so you can use a beer trap to eliminate them. You dig a small hole near the plant. Then place a small tray filled with beer in this hole.
The slugs will be attracted to the beer and get intoxicated. They won’t be able to crawl out of the tray and hole. This will cause them to drown in the beer itself.
2. Aphids
Aphids are small insects that live on the foliage of the marigold plant. You’ll find them on the leaves and stem. Do check under the leaves as they may hide there.
The aphids can be hard to see because they are tiny and can be green in color. They can also have other colors such as white, yellow, and orange.
The aphids will not eat the leaves but stick holes in them and suck the sap out of them. The aphids will also leave a sticky residue known as honeydew. This will cover up the leaves. The honeydew is sweet and will attract ants to the plant.
These problems will cause the marigold leaves to turn yellow due to a lack of nutrients. They will eventually die and fall off.
Once you know aphids are attacking your marigold plant, it’s easy to get rid of them. You need to spray water on them and dislodge them to the ground.
The aphids can’t get back to the plant, so they will go away or be eaten by their predators. Make sure to do this several times during the week till you can get all the aphids out of the marigold plant.
Another solution is to sprinkle diatomaceous earth on the marigold foliage. This is a white powder obtained from fossilized remains of diatoms in the sea.
I’ve written an extensive guide that will help you use diatomaceous earth on the marigold plant to get rid of scale insects.
The diatomaceous earth powder contains sharp microscopic edges. So when aphids move over this material, their soft bodies get cut.
Make sure to coat both sides of the leaves to get rid of all the aphids. You need to keep applying the diatomaceous earth every week till all the aphids are eliminated.
You can also read this post where I will show you 7 ways to get rid of aphids from your marigold plants.
3. Thrips
Thrips are winged insects that may be yellow, green, black in color. They are similar to aphids when attacking the marigold plant.
The thrips will suck the sap out of the foliage causing a lack of nutrients in the leaves. They will turn yellow or brown in color and eventually die.
The best way I know to get rid of thrips is to use a mixture of neem oil or insecticidal soap. Take 1 teaspoon of neem oil, 1/2 teaspoon of dish soap, and a quart of clean water.
Mix them all well and add them to a spraying can. Spray one leaf of the plant and leave it for 24 hours. Make sure there is no adverse reaction to this mixture on the leaf.
You can then spray the mixture every week on all parts of the marigold plant to get rid of the thrips. Keep doing this until no thrips are remaining on the plant.
Read this post where I will show you how much neem oil you should use and how you can use it on your marigold plants. You don’t want to use too much because it’s toxic to the plant.
4. Spider mites
Spider mites are tiny creates that build white webs on the foliage of your marigold plant. They are related to spiders rather than insects.
They dig holes in the foliage of the marigold plant and drain them out of nutrients. The leaves will eventually turn brown and die.
It’s easy to get rid of spider mites using the same solution as for thrips. You can mix 1 teaspoon of neem oil with 1/2 teaspoon of dish soap.
Add this mixture to a quart of water and mix it well in a spraying can. Spray this mixture on the affected parts of the marigold plant every week. Keep doing this till all the spider mites are eliminated.
5. Birds
Birds can be beautiful visitors to your garden but some of them can mess up your marigold plants. Some such culprits include crows, blackbirds, and robins.
These birds don’t necessarily eat the marigolds and leaves, but they are attracted to slugs and snails. So they tear up the flowers and leaves in search of these treats.
The easiest way to protect your marigold plants from such birds is to cover them with netting or grow them inside a tomato cage.
You can also think of using a bird-scaring technique such as hanging shiny objects like CDs or ribbons near the marigold plants.
The problem with such techniques is clever birds like crows and blackbirds get used to it after a while. So you need to keep switching these techniques from time to time.
6. Animals
The marigolds have a pungent smell and taste that repels many animals. But some animals will still eat the flowers and leaves. Or they may just destroy the plants trying to get to some other plants in the garden.
If you have pets like cats or dogs, they may try to tear up the leaves and flowers out of curiosity. They may even eat the leaves when they have some digestion issues or stomach infections.
You will need to protect the marigold plants from cats because their pee can kill the plant. I’ve written a post that will help you keep them away from your marigold plants.
Animals like rabbits, gophers, squirrels, and chipmunks would try to munch on the leaves and flowers when in dire need of food.
The best solution is to cover the marigold plants with netting to protect them. Another option is to use fencing that is at least 3 feet tall to keep such animals away.
Make sure the fencing goes deep into the ground so animals like rabbits, gophers, and voles can’t dig underneath the fencing.
A simple solution is to spray some hot pepper tea near the plants. You can make such tea by chopping up hot pepper and mixing it with a cup of hot water and white vinegar.
Cover the mixture for 5 days and let it rest. You can then strain the mixture in a spraying can. Add in 1 teaspoon of dish soap and 1 tablespoon of vegetable oil.
Mix this well and you can spray it near the plants as well as on the plants to keep animals away.
Some other options are to use a motion-detection sprinkler system. Or a repellent that raises an alarm when an animal strays close to the plant.
Diseases
Diseases will not “eat” your marigold plant but their effects might make you feel that’s the case. The most common problem is fungal diseases that will cause the leaves and flowers to decay and drop off.
Fungal diseases are attracted to the plant in moist conditions. The best way to prevent fungal diseases is to avoid moist conditions near the marigold plant. Make sure to water the base of the plant and avoid splashing water on the foliage.
Water the plants in the morning so that any excess water will evaporate once the sun comes out. This post will show you the best way to water the plants, how much to water, and some good watering systems.
Also, don’t have the plants growing close to each other. This will block sunlight and airflow causing humid conditions to develop.
7. Root rot
Root rot can happen if you overwater the plant and it’s collecting near the roots. It means there is not good drainage in the soil or container.
The roots start decaying, and if you look at them they will have turned brown, soggy, and smell. The only solution is to take out the plant, cut off the affected roots and replant in another location or pot.
If all the roots are affected, then you can’t do much and need to dispose of the plant.
8. Botrytis blight
This is a fungal disease that can affect marigold plants in moist conditions. It’s common to see this issue after rain.
The fungus causes brown spores on the plant. The leaves may develop brown lesions and the bugs will start turning brown.
The best solution is to cut off the infected parts of the plant with a pruner. Make sure to sterilize the pruner with rubbing alcohol before each cutting. Otherwise, you risk spreading the fungus to other parts of the plant.
If you’re looking to buy a pruner, I’ve written a detailed review of some of the best bypass pruners you can choose from. You can get a good deal on Amazon so make sure to check it out.
If the infection has spread on the entire plant, you can consider using a fungicide to get rid of the problem.
9. Leaf spot
This is a fungal disease that causes brown spots on the leaves with the infected spores. These spots keep on increasing and eventually turn the entire leaf brown. The leaves will then die and fall off.
The best solution is to cut off the diseased leaves from the marigold plant. Make sure to use sterile pruners to do this. You can use rubbing alcohol to clean the blades before cutting the leaves.
If the problem is severe, you can dispose of the plant. Or try to use a fungicide to get rid of the problem.
10. Verticillium wilt
This is probably the most dangerous of the fungal diseases for the marigold plant. Once the plant is infected with verticillum wilt, it can’t be saved.
The fungus invades the plant from the root system through the stem and to the leaves. It will cause discoloration of the stem, leaves, and buds.
If you cut the stem of the plant, it will have a brown ring inside which helps identify that the plant has been infected with verticillum wilt.
The plant will continue to grow but the disease will keep spreading and eventually the plant will die. The best you can do is dispose of the plant and grow another one.
You cannot grow plants susceptible to verticillium wilt in the same soil as the fungus will remain in it for several years. You will need to grow them in another location. You can clean the soil of the fungus by heating it using solarization.
Wet the soil well and then cover it up with a black plastic tarp. Keep it covered for 2 to 4 weeks so that the soil can heat up. The top 6 inches of the soil should heat up to ensure that the verticillum wilt fungus has been killed.
Fact Checked, Written, and Published by Kevin Rodrigues
Kevin is the founder of Gardening Mentor, a website that aims to teach people to grow their own food in a limited space. As a self-taught gardener, Kevin has spent several years growing plants and creating gardening content on the website. He is certified in Home Horticulture and Organic Gardening from Oregon State University. He has a Post Graduate Diploma in Horticulture and Landscape Gardening from Mumbai University.
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