Copyright © 2020 Clemson UniversityClemson Cooperative Extension | 103 Barre Hall Clemson, SC 29634864-986-4310 | Contact UsHGIC@clemson.edu, College of Agriculture, Forestry and Life Sciences, Centipedegrass Yearly Maintenance Program, Bonide Systemic Insect Control Concentrate, Bayer Advanced Vegetable & Garden Insect Spray Concentrate, Gordon’s Zylam Liquid Systemic Insecticide (drench). Rose slugs are the larvae (immature forms) of sawflies, non-stinging members of the wasp family. They can be effective at reducing adult populations, but they should be kept at least 50 feet from the plant(s) that you are trying to protect. Rose slug feeding on leaf surface. See Table 1 for products containing these insecticides. Insecticidal soaps will help control thrips, but thorough coverage is necessary. The larvae generally reach about ½-to ¾-inch in length. Once dislodged, they cannot climb back onto the plant. Since the oil must be in contact with the pests to work, you must be sure to completely spray all foliage, including the underside of all leaves. Table 1. Adult female thrips of both species are tiny, yellowish-brown insects with fringed or feathery wings. Often, more than one control option is available for a pest. As some species of rose slugs get larger, they chew large holes or the entire leaf with only the midrib remaining. Control: Aphids have several natural enemies, including parasitic wasps, ladybird beetles (ladybugs) and larvae, and green lacewing adults and larvae. The following insecticidal sprays are effective against rose leafhoppers: acephate, bifenthrin, cyfluthrin, lambda cyhalothrin, malathion, or permethrin. Good choices that are effective, but have little environmental impact, include insecticidal soaps and narrow-range oils. The stippling spots may merge, causing leaves to appear almost white. Soil drenches or granular applications of imidacloprid or dinotefuran will control aphids and last longer within the plant to prevent future infestations. Many of these beetles feed mainly on flower buds or open blossoms, but can feed on leaves. Damaged leaves may drop prematurely. Clemson University. Anne W. Gideon, www.insectimages.org. Regular inspection of roses is important because feeding typically progresses quickly and extensive leaf skeletonizing can occur if infestations are not noticed. Apply all pesticides according to label instructions, following all precautions. Crawlers are very small and will appear as moving specks of dust. Aphids feed on plant sap with their piercing-sucking mouthparts. Foliar injury from soaps and oils may occur on plants under drought stress. Webbing can collect dust, making the plant look dirty. Insecticidal soaps have no residual action, so the solution must make direct contact with rose slugs in order to be effective. Both immature and adult thrips feed by scraping surface cells to suck plant sap. Mites are not insects but are more closely related to spiders with eight legs as adults instead of six. Horticultural oils applied at higher rates of 3% to 4% during the dormant season (i.e., to a rose bush that has lost its leaves) will penetrate the thick waxy covers of the overwintering adults. In the spring, the young nymphs (immature forms that resemble adults but are wingless) emerge from the cane. U.S. National Collection of Scale Insects Photographs Archive, USDA ARS, www.insectimages.org. With severe infestations, leaves may develop a grayish green or bronze color, and webbing may cover both sides of leaves as well as branches. The waxy covering or “scale” protects adult scale insects from many insecticides. Insecticides are available but timing of sprays is very important. One way to detect them is to hold a piece of white paper under a branch and then tap the branch sharply. ; & RTU. See Table 1 for examples of brands and products. Between feeding by the nymphs and adults, and egg laying by adult females, a severely infested rose bush may be killed. You can also make your own insecticidal soap by mixing 1 to 2 tbsp. Spider mite (Tetranychus urticae) webbing and plant injury. Avoid using broad spectrum insecticides that will damage the beneficial insect population. The soap spray must contact the pest to be effective, and may require three sprays at 5- to 7-day intervals. Adult scale insects have an unusual appearance. Rose scales are usually found on rose canes where they feed on sap with their piercing-sucking mouthparts. Dealing with a Sawfly Problem. These inspections increase the likelihood that a pest infestation will be detected early, when pest numbers are low and control is easiest. In a spray … Also, avoid pesticides that claim to “suppress” mites as they tend to be weak miticides. When only a few plants are involved, fine netting, such as tulle fabric, can be placed over the bush or individual blossoms to exclude the beetles. As such, broad spectrum insecticides that may kill these beneficial predators should be avoided. For more information on the cultural requirements of roses, see HGIC 1172, Growing Roses and HGIC 1173, Pruning Roses. Japanese beetles have chewing mouthparts and feed on flowers, buds and leaves of roses (as well as numerous other plant species). This method is most effective with light infestations as seen with early detection. Metamorphosis is complete: egg, larva, pupa, adult (Borror, Triplehorn and Johnson, 1989). Generally, rose slugs feed at night. If you want to control the pests on your roses without using toxic chemicals, you can try organic insect treatments. An unusually severe leaf cutting injury to wild rose by leafcutting bees (Megachile sp.). Adult rose leafhoppers (Edwardsiana rosae) vary in color from white to gray to yellow to green. Insecticidal soap and horticultural oil are also effective against rose slugs. Typically, flowers and buds that have been fed on have ragged edges and/or holes in the petals. Control: Various non-chemical control options are available for Japanese beetles. Insecticidal sprays with acephate, bifenthrin, cyfluthrin, lambda cyhalothrin, malathion, permethrin or pyrethrin will control grasshoppers. Several species of scale are pests of roses, but rose scale (Aulacaspis rosae) is one of the most serious. Two-spotted spider mites (Tetranychus urticae) and southern red mites (Oligonychus ilicis) are pests on roses in South Carolina. In addition, with their coloring, they can be very difficult to spot on leaves. John A. Weidhass, Virginia Tech, www.insectimages.org. This will remove the insect from the plant and will ensure that it does survive to reproduce. Adult rose scale (Aulacaspis rosae) on a rose cane. As the weather cools, the grubs move more deeply into the soil to overwinter (survive the winter). For information on diseases of roses, see HGIC 2106, Rose Diseases. Grasshoppers are general feeders that feed on the foliage of many kinds of plants. A strong spray of water is a non-chemical control option that removes eggs, larvae (six-legged immature stage), nymphs (eight-legged immature mites) and adult mites. See Table 1 for examples of brands and products. Early damage is seen as yellow or white speckling on the leaf’s upper surface. When a plant is disturbed, they hop or fly away quickly. They suck plant sap, typically feeding on the lower surface of a leaf. An adult Japanese beetle is about ½ inch long and has a metallic green body and legs with coppery-brown wing covers. In addition, because rose blooms expand rapidly, it is difficult to keep them adequately covered with insecticide. When growing roses, the use of broad-spectrum insecticides should be avoided as much as possible as these products can kill off natural enemies that help keep spider mite populations in check. Stem canker can result in plant death. Make sure that you spray early in the morning or on cooler days if possible. Since many beetles feed mainly at night, the gardener rarely sees them, only the damage that they cause. These circumstances make it difficult to keep the blooms adequately covered with insecticide to protect them. Water the plants well prior to spraying. Soil drenches or granular applications of imidacloprid or dinotefuran, will control Japanese and other beetles and last longer within the plant to prevent future infestations. Japanese beetle traps are available commercially, but should be used with caution. Nymphs and adult leafhoppers feed on the undersides of leaves, using their piercing-sucking mouthparts to suck plant sap. Wipe your hand over the paper. With a heavy infestation, rose scale can cause cane decline or twig dieback. Their natural enemies tend to keep aphid populations under control except in cool weather. Unfortunately, the numerous insects and related pests that attack them can make growing them “interesting”, if not outright challenging. Another aspect of sawfly insect … A low population of aphids does little damage to a rose bush; however, aphids reproduce very rapidly and can quickly reach numbers that cause damage. If ants are present, they should be controlled. Leaving even one aphid alive can result in a large population very quickly. With light infestations, scale can be scraped off by hand and destroyed. Some insects, such as weevils and Japanese beetles, are best controlled by picking the adults off the rose manually and dropping them into a bucket of soapy water. If a chemical control is necessary, the least toxic chemical should be used, being sure to apply it when a susceptible stage of the pest is present.