Pests on Roses

by Karen Miller, Permian Basin Master Gardener Entomology Specialist

With Spring just around the corner, our roses are beginning to leaf out. Insects are also coming to life. Insect eggs that were deposited in the fall and survived the winter will begin to hatch, and the insects that burrowed into the soil or leaf litter will be emerging as the days get warmer. These pests will be looking for a good meal after their long winter’s nap. Roses are a target of some of these hungry survivors.

Identification is the first step to controlling the insects preying on your roses. Hopefully this article will provide information for identifying and controlling common insect pests that are found on the rose.

Aphids on Rose bud

First and foremost is the Aphid. Aphids are sucking insects that show up early in Spring. These insects are small, oval shaped, light green or pinkish and very easy to overlook.  They reproduce rapidly, attacking the stems and buds, even before the bud opens. Aphids produce a sweet, sticky substance called honeydew. This honeydew is a host for black sooty mold and will attracts ants.

Aphids are easily controlled by just a strong jet of water from your hose, or spray them with insecticidal soap.  The soap will also wash off sooty mold. Roses can be treated with neem oil or pyrethrum, both are considered a less-toxic method of control.

Thrips

Thrips are tiny, slender sucking insects that are usually yellow, brown or black. These pests are also very difficult to see.  They feed on flower petals in early summer and cause discoloration and deformities as the bud begins to open. Thrips will feed on all roses but seem to prefer light-colored varieties

Many beneficial insects feed on thrips, especially lacewings. Insecticidal soaps are effective in getting rid of the thrips, as well as neem and pyrethrum.

Spider mites

Spider mites usually arrive with a hot, dry summer. These tiny arachnids are very hard to see without a magnifying glass, but a fine webbing on the underside of the leaf is a sure tip off that they are there. As they suck the plants juices, the leaf will turn yellow with a silvery sheen.  The plant will start dropping leaves if the infestation gets really bad.

Spider mites can be controlled by a blast of water from the hose, make sure to target the underside of the leaves. Insecticidal soap and horticultural oil are effective as well.

Cottony Cushion Scale is just one more sucking insect that will attack roses. It also produces honeydew. This scale insect lays its eggs on the rose stem in the fall. When the eggs hatch in late spring the young scale insect begins to seek a spot to secure itself. Scale is a white, rounded, limpet-looking body on the rose stem. The egg cases that are left behind resemble white cottony masses.

These bugs create a protective scaly or crusty shell over themselves. Spray them with horticultural oil when they are in the crawling stage for best results.

The Rose is a testament to our love of beauty. Everyone may not enjoy growing the Rose, but it is widely grown, admired and has captivated many plant breeders attention. Each breeder competing to create the ever-beautiful, versatile Rose.

Some quick final tips to help protect your roses from insect pest:  Inspect you roses several times a week. Pests reproduce quickly, be diligent in your inspections to stay ahead of the insects and detect any problems before they become unmanageable. Please remember Spring also brings the beneficial insects out of hibernation. They are our partners in controlling pest outbreaks – not just on roses, but all through our gardens.

Hopefully this will help you in identifying and controlling insect pest that prey on your roses. If you have questions, you are welcome to call the Ector County extension office 498-4071 or the Midland County Extension office 686-4700.

2-26-2016