When your roses are given the proper attention and a healthy environment, they will stay healthy and will flourish for many years. However, even under the best of conditions, your roses may on occasion suffer some form of disease or be troubled by common pests. Inadequate drainage, poor soil, insufficient water, lack of nutrition or other environmental problems may encourage pests and disease to take hold of your roses.
Roses may be affected by either environmental conditions or living pathogens. If you find that the damage to your roses is uniform, then it is usually an environmental or cultural problem that you are dealing with. However, if there is visible damage that is not uniform, then you are usually dealing with a problem with living pathogens.
Today and tomorrow I will discuss how to identify and treat the most common insect problems in your roses. Next week I will discuss how to identify and treat the most common diseases which may affect your roses.
Symptoms: Masses of small insects on the buds and leaves.
Cause: Aphids—these are green, red or black bugs which are soft and about 1/8” long. They can be found in clusters and will be found mainly on the new growth. These pests appear in the spring and can remain all summer.
Treatment: You will want to begin by simply hosing the insects off of the rose plant with water. Should you need to treat the problem further, then most of the commercial insecticidal sprays are effective. You can also use a solution of household dish soap and water. This is done by using just a few drops of dish soap in a quart spray bottle and filling it up with water. Then just spray it on your roses. There are also many aerosol insecticides labeled for plant pests that will also work. Just be sure to read the label on the product to verify which insects the product will control. Spray the product upwind and ensure that you apply a coverage that is thorough. Or if you want to just make life easy on yourself, go to your local garden center and purchase a product called Spinosad. This is an organic chemical that will control most insect problems in your roses.
Symptom: Buds are distorted and bloom tips appear discolored.
Cause: Thrips—these are light brown insects which are very slender and are about 1/8” long. These insects can appear inside petals and they move very quickly. They are spread by the wind.
Treatment: You will want to apply a systemic insecticide that lists thrips as a target. You will want to apply this when new growth of 1” or more emerges in the spring. Contact treatments can be used on a rotational basis when the rose buds are pea-sized. Or, just make life easy on your self and go and get some Spinosad from your local garden center.
Symptom: Leaves stuck together, unopened buds with holes.
Cause: Omnivorous leaf roller—this is a moth larvae that makes a cocoon type of structure with leaves.
Treatment: Remove all of the cocoon structures from your rose plant. If you need to treat your rose plant further, then apply a systemic insecticide that targets leaf rollers when new growth of 1” or more emerges in the spring. Contact treatments can also be used on a rotational basis when the buds of the roses are pea-sized. Personally, I just use the Spinosad as it is easier.
Symptom: Leaves appear fuzzy and yellow on surface; underside has small red specks, webbing or spider-like insects may be seen.
Cause: Spider mite (red spider or 2-spotted mite)—these insects are microscopic in size, but are visible to the naked eye. Spider mites thrive in hot weather.
Treatment: Apply an insecticidal soap, horticultural oils, miticides, or high pressure hose water, or my favorite product, Spinosad. All of the treatments must be applied to the underside of the leaves of the rose plant, in order to come into contact with the spider mites. Keep the roses well watered during hot weather and avoid dust on the leaves of your plants.
Tomorrow I will discuss Beetles, Rose Midge, Leaf Cutter Bees and Rose Cane Borer. Which of the above treatments do you favor for the treatment of your roses? Leave me a comment and share.
Photo provided by Major-Maróthy Szabolcs