Geraniums (Pelargonium x hortorum) kept as annuals or perennials are among the most popular garden and container plants in the United States today.
For the most part, healthy geraniums are pest-free.
However, plants that are kept in less than optimal conditions may be subject to predation by:
- Geranium BudWorms
- Four-Lined Plant Bugs
- Fall Cankerworms
- Cabbage Loopers
In this article, we’re going to share information to help you identify and defend against these common geranium pests.
How To Defend Your Geranium Plants Against Common Garden Pests
When protecting your Geranium plants against pests of all sorts, frequent inspection of the plants and leaves is advised.
The best defense is a good offense, so inspect your plants regularly so that you can detect and identify pests and diseases early on.
If you begin treatment as soon as you notice a problem, you are much more likely to deal with it successfully.
Once you’ve identified your Geranium pest problem, there are five basic treatment techniques you may wish to use.
Introduce Natural Predators
Ladybugs do a great job of keeping aphids and other small, soft-bodied, sap-sucking pests under control.
Beneficial wasps do a good job of tackling big pests, such as caterpillars.
Other good natural predators include:
- Predatory Gall Wasps
- Minute Pirate Bugs
- Predatory Mites
- Parasitic Wasps
- Parasitic Flies
- Big Eyed Bugs
- Flower Flies
Birds, lizards, frogs, and toads are also excellent natural insect hunters.
If you take steps to develop a robust population of natural predators in your garden, you are unlikely to be bothered by pests on any of your plants.
Check with your local garden center, gardening clubs, your county agent, or online for sources of live natural predators to add to your garden.
Spray Larger Infestations With Insecticidal Soap
If you do not notice an infestation of pests until it has become rather large, you can deal with it by spraying insecticidal soap every two days until the presence of the pests subsides.
Insecticidal soap is effective against a wide variety of small, soft-bodied pests.
It is not effective against large pests, such as Four-Lined Plant Bugs and caterpillars, nor is it effective against slugs and snails.
For these bigger critters, you need to pick them off when you see them and take follow-up steps to bring about their demise.
Spray Horticultural Oil
Horticultural oil like Neem oil is a good alternative to insecticidal soap.
It has the advantage of having a bit of staying power which empowers it to both treat and prevent pest infestation.
- Apply horticultural oil spray a couple of times a week, early in the morning or at dusk.
- Be sure to coat all surfaces like stems and leaves of the plant thoroughly.
- Do not to apply the oil during the hot, sunny times of the day because it will magnify the rays of the sun and may cause damage to your plants.
Use Bacillus Thuringiensis var. Kurstaki (Bt) To Combat Caterpillars
The moment you see any pest caterpillars on your plants, such as Geranium Budworm or Tobacco Budworm, Fall Cankerworms, and Cabbage Loopers, pick off all of them that you can see and drop them into a bucket of soapy water.
Follow up with an application of Bacillus Thuringiensis.
Be advised that Bacillus Thuringiensis will not kill caterpillars right away. It takes time to work.
When the caterpillars eat the Bacillus Thuringiensis, it causes them to swell up and die, but this can take a few days. This is especially true with larger caterpillars.
Small caterpillars tend to succumb to the treatment more quickly, so some gardeners apply a preventative treatment of Bacillus Thuringiensis early in the growing season to catch them while they are small.
Just remember that you must reapply Bacillus Thuringiensis after heavy rain because it will be washed off your plants.
Remember that Bacillus Thuringiensis kills all sorts of caterpillars, so take some time to identify your caterpillars before you use them.
Geranium Budworm caterpillars are typically brown with green markings.
Butterfly caterpillars come in a wide variety of colors and patterns.
If you find butterfly caterpillars, remove them and relocate them to a more appropriate setting, such as your butterfly garden.
Establish A Good Slug And Snail Control Program
It takes a combination of methods to control slugs and snails effectively.
Begin by eliminating areas where they can hide, such as under stones and boards and in debris and damp ground covers.
As with caterpillars, keep an eye out for snails, pick them up and drop them into a bucket of soapy water when you find them.
You can lure them to “collection points” by watering an area and then leaving loose boards or melon rinds out to attract them. They will hide underneath.
Snails and slugs can also be lured by beer poured into a container with slick, vertical sides. To lure them, you can do the following steps:
- Bury the container into the ground so that the top of the beer is even with the soil surface.
- Pour an inch or two of beer in the bottom.
Snails will go in to get the beer. Once they’re inside, they won’t be able to get out, and they will drown.
You could also install copper barriers around flower beds and wrap copper tape or foil around planters to keep snails out.
When the slimy snails come in contact with copper, they experience an electrical shock.
This will work until the copper becomes tarnished. When this happens, you must replace it.
Pour a thick ring of food-grade diatomaceous earth (DE) around flowerbeds to keep snails and slugs out.
This coarse material is painful for them to move across. Remember to replenish your DE barrier after every rain.
Domestic fowl, such as chickens, ducks, guinea fowl, and geese also enjoy a meal of snails and slugs.
You can also encourage other natural predators, such as:
- Ground Beetles
A comprehensive, ongoing program of slug and snail abatement that consists of a combination of the methods listed here should be effective.
But avoid using salt to kill slugs and snails because it contaminates the soil.
Use poison bait as a last resort because it can have many unintended victims.
For Severe Insect And Caterpillar Infestations, Use Pyrethrin Pesticides
If the infestation has gotten way out of hand, you may need to use a more powerful pesticide to get it under control.
Pyrethrin sprays are relatively safe and are effective against a wide variety of pests.
Those containing synthetic pyrethrins are even more effective.
Look for products containing one of these chemicals:
Generally speaking, you should apply the product three times a week until you have eradicated the infestation.
Be sure to double-check package directions and follow them closely. Remember, the label is the law.