Gardeners often find themselves at their wit’s end when they see their plants being gobbled up in the middle of the night. But what are these critters, and why are they feasting on your beautiful flowers?
First, it is important to note that both caterpillars and slugs can be guilty of consuming our lovely leafy friends. However, there is a better chance that it is a slug. Slugs eat plants because they contain a certain type of salt that slugs crave. Indeed, the slugs will actually have a limited selection of plants they can eat: only those that won’t be missed by their other friends. However, while they may not like losing out to other hungry friends, their favorite plant isn’t that much better.
So what is it about your plants that slugs love? Most likely, the answer is chemicals in your barberry plant or ivy that they can eat and use to their own advantage. Slugs are carnivorous animals born with big mouths and big appetites. After finding a plant that contains the chemical they crave, or that is well-protected against being eaten by their other, more voracious, friends, they will go on a feeding frenzy.
The slug that has eaten your barberry plant and left behind its remains probably was the same one that ate your zinnia. Slugs generally do not eat by themselves. When they find a tasty treat, they regurgitate the food for their friends. However, once they have enough of their favorite plant to feed more slugs (or more likely, with enough leaves to keep them satisfied), they simply walk away and leave the rest of the plant for you to harvest. As a result, gardeners often find their plants chewed up and dug up overnight–just like the one in the picture.
To stop this night-time activity, gardeners must install barriers at night to make it unattractive for slugs to walk through your garden. This can include laying down mulch or gravel and avoiding planting in that spot again, or sprinkling diatomaceous earth on top of the ground. You can also buy commercial slug traps from many home improvement stores and online retailers. These traps lure slugs to their death by using salt as bait.
Signs of insects and slugs
So what do the clues look like? The best way to tell if your flowers have been eaten by slugs or caterpillars is to look at their backsides (don’t worry–they can’t hurt you!). Caterpillars will leave behind a silky webbing on grass, which resembles a tent. If the webbing is bare in the morning, then it almost certainly was a caterpillar that was feasting on your plants. Another sign of caterpillar damage includes smooth white pellets that can be found around leaves that were eaten. If the damage caused was minor, then your plant may recover from the attack.
If you notice a divot from the middle of your plants, then it’s likely that slugs have been nibbling on them. The slugs will frequently leave behind casts of their body, or slime trails. If both of these signs are present, then it is likely that your flowers were attacked in the night by slugs!
Caterpillars leave fecal droppings behind, which are little black pellets. However, they will not always leave pellets behind as they are not always present in the middle of the grass. This makes detecting caterpillar damage more difficult, but if you are able to find these little guys then you can stop them from eating your plants by introducing a natural predator like a snail or praying mantis.
There are three ways to keep slugs away: alter the habitat so they cannot hide; kill them with toxic bait or traps; and remove and dispose of them with salt or sticky tape. The first method is much preferred, because it is safer for people and pets. Habitat modification is best accomplished by laying down a 4 to 6-inch layer of gravel or mulch. Water should be directed away from the garden to prevent slug eggs from hatching. Products like Sluggo, Escar-Go, and Kaput can be used as bait or slug traps to kill slugs.
If you want to use a chemical control, you should choose sprays that are labeled “for slugs only” because they will not harm beneficial insects or pets. If you use salt as bait, it should be placed on the soil and watered in so that it penetrates the ground and kills any hidden slugs. Sticky traps can be effective; however, they can only trap one slug at once.
Piercing/sucking insects are capable of piercing through leaf tissue and sucking out the contents of a plant. Insects in this category include aphids, leafhoppers and their relatives, caterpillars, whiteflies, mealybugs, scales, thrips, psyllids, and spittlebugs.
If a plant is infested with piercing/sucking insects it may show one or more of the following symptoms: leaves may be browned or rolled; there will be sticky honeydew on leaves; black sooty mold may appear on the plants; leaves will become distorted or wilt. Severe infestations can kill plants.
The best way to control piercing/sucking insects is to apply 1 ounce of insecticidal soap (like Safer) per gallon of water, and spray on the plant foliage as needed. Allow the soapy solution to remain on the leaf for 5-10 minutes, but no longer. This will kill the insect and prevent it from irritating your plants again.
Root-feeding and stem-feeding insects
Root-feeding insects, such as the chafer beetle, feed on plant roots. However, other insects feed on stems and can cause considerable damage to a plant, like the leaf-footed bug or stinkbugs. Other insects feed on stems and can cause considerable damage to a plant, like the leaf-footed bug or stinkbugs.
Wildlife (rabbits, voles, woodchucks, deer, squirrels)
Attracting wildlife can be a positive experience. Birds, butterflies, and bees are all attracted to the nectar in flowers. However, there are some animals that live in a forest or landscape that can cause problems by their mere presence.
Deer are one of the most common culprits when it comes to damaging plants. Deer will browse on new growth or terminal buds of woody plants, especially ornamental shrubs and trees. However, some people have reported they only eat the top foliage from “tender” perennials such as hosta or daylilies. Deer tramplings have been known to kill plants as well.
Moles are another problem that can be caused by wildlife. Moles can burrow under the ground of tall grasses, native plants, and trees causing damage to roots or whole plants. The mole tunnels eventually close up, creating a mound called a “mound”. A mound will typically be several feet across and many feet high. Measuring for mounds is an effective way of identifying if there are moles in your yard.
Rabbits and woodchucks are sometimes seen eating the bark off of trees, shrubs, and herbaceous plants. It is important to identify if the damage is caused by rabbits or woodchucks as different management techniques are required for each animal.
A good yard care practice is to remove sources of water for wildlife in and around your yard. You can be proactive by installing caps on bird baths to prevent water from freezing over in winter, as well as deterring mosquitoes. Landscape fabric or synthetic mulch will help control weeds while limiting ground cover.
Organic treatment solutions
- Beneficial insects
Natural enemies of these pests include predatory insects such as ladybugs, lacewings, hover flies, parasitic wasps and spiders.
Nematodes are microscopic worms that feed on the roots of some plant-eating pests. They come in a variety of species and potting soil brands contain different species. You can purchase these worms from garden centers or have them shipped to you with a specific nematode product for use with your particular need. A common example is Steinernema carpocapsae which will be sold as Steinernema feltiae (Putumayo brand) or Rearing media-Steinernema feltiae (Safer brand).
- Some organic insecticides are derived from natural sources, such as plants. However, while they may be less toxic than many synthetic chemicals, they can also kill birds and other wildlife and cause environmental damage.
- Botanical insecticides are as effective as chemical insecticides; however, they have the added benefit of not being poisonous to people and animals. Botanical insect repellents work by masking human scents that attract insects
- Barriers and traps.
- Gardening row covers, also known as floating row covers, are a type of fabric that is placed over crops to protect them from frost and pests. Row cover is most often used in the spring to help control
- Pesticidal soaps are soaps that have been formulated to kill insects. They are usually manufactured in order to combat infestations, and they are most often found in the form of a liquid.