Caterpillars on Roses


The rose (Rosa spp.) is a genus of shrubs that produce blossoms that are often quite strongly fragrant. The members of this genus flourish in gardens all throughout the United States, in plant hardiness zones ranging from 2 to 11, according to the United States Department of Agriculture. The management of these lovely but fussy plants may be challenging at times, but one of the more manageable challenges in the rose garden is the prevention of caterpillars from feeding on rose bushes.

Fruittree Leafroller Caterpillar

According to the University of California Statewide Integrated Pest Management Program, fruittree leafrollers (Archips argyrospila) are small caterpillars that are semi-transparent green in colour and have black heads. While feeding, these caterpillars may hide inside of leaves that have been folded over on themselves. These green bugs on roses like fragile new leaves, but if numbers are high and young leaves are scarce, they will move on to older leaves. Fruittree leafrollers are most active from March until roughly the middle of May. After emerging, they eat for about 30 days before entering their pupal stage for 8 to 11 days. They live for one week, during which time they mate and produce a large number of eggs, and then they expire. The eggs will stay on the roses until the spring, when the larvae will hatch and feed.

Omnivorous Looper Caterpillar

The name of the omnivorous looper, also known as Sabulodes aegrotata, comes from the animal’s distinctive mode of movement. According to the University of California Statewide Integrated Pest Management Program, this 2- to 2.5-inch-long caterpillar glides on leaf surfaces by arching its back and sliding its rear set of legs toward the front set of legs. This behaviour may be seen while the caterpillar is travelling. The bodies of omnivorous loopers are green, with yellow, green, pink, or black stripes running down their bodies. Their heads are brown. When feeding, they will skeletonize the leaves, but they will not form webbing.

Orange Tortrix on Roses

Orange tortrix caterpillars, also known as Argyrotaenia citrana, are practically translucent, orange-colored caterpillars that do not have any distinguishable markings and prefer to eat in the higher parts of the rose canopy. The University of California Statewide Integrated Pest Management Program says that when they eat, they make some fine webbing and may hide behind rolled-up leaves like the fruittree leafroller. This behaviour is characteristic of the pest. Orange tortrix are capable of causing significant damage to plants that produce fruit, however they will only eat the leaves of roses.

Tent Caterpillars on Rose Bushes

Many species of caterpillars that belong to the genus Malacosoma are collectively referred to as tent caterpillars. These hairy caterpillars spin huge cocoons out of silk and weave them into the canopies of rose bushes, where they then encase the leaves that they feed on. According to the Statewide Integrated Pest Management Program of the University of California, tent caterpillars will only consume the sensitive tissues of a plant’s leaves and will cease eating at the veins and stems. Control may be difficult due to the nest’s protective barrier, but it can be eased if a hole is torn in the silken mat and spray is applied within.

Tussock Moth Larvae

Another notable spring-hatching rose defoliator is the bristly, vividly coloured larvae of the Western tussock moth (Orgyia vetusta), which is found in western North America. According to the Statewide Integrated Pest Management Program of the University of California, these black caterpillars have conspicuous horn-like tufts on their heads and hairy tufts along their bodies. Down with the four different tufts of hair that sprout along their backs, they develop patches of red and yellow as they become older. Each year, there may be as few as one or two generations of Western tussock moths that hatch.

Non-Chemical Caterpillar Control

In terms of the insects that may be found on rose plants, a mild infestation of caterpillars does not pose a significant risk to the roses’ health and can be readily eradicated by hand. Pick the individuals off of the leaves where you see them eating, and place them one at a time into a basin of soapy water. If you want to get rid of all of the caterpillars, it’s possible that it will take many weeks of vigilant monitoring of your plants. In the event that leafrollers or tent caterpillars are the source of your issue, you may be able to remove the unattractive nests from your bushes if the infestation isn’t too widespread.

Best Insecticide for Roses

According to the Statewide Integrated Pest Management Program at the University of California, the use of insecticides is seldom required in order to manage caterpillars. Insecticides with a wide range of activity are not as efficient as sprays that have been developed expressly for caterpillars, and they have the potential to harm beneficial insects that would otherwise feed on or parasitize these pests.

Bacillus thuringiensis is a soil bacterium that may be purchased commercially. It is harmless for honeybees, people, and the environment, and it creates endotoxins that kill the gut wall of caterpillars, grubs, and maggots. However, it does not kill adult insects. The nervous system toxin spinosad may be used for caterpillars, but only with extreme care since it poses a threat to bees until it has had a chance to dry. Spinosad should not be applied until dark, when most of the bees who were out foraging have returned to the hive.