Pests of roses	AG0516
David Williams and Kathy Pullman, Knoxfield June 2000

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Roses are attacked by a variety of chewing, sucking and rasping (scraping) pests. This Agriculture Note provides a general description and the biology of major rose pests from the above three groups

Chewing insects

Lightbrown apple moth (Epiphyas postvittana)
This moth is a native insect which attacks many plants, including roses, fruit crops, ornamental shrubs, legumes, docks, capeweed, blackberry and wattles.

Young larvae graze on leaf surfaces, and older larvae chew holes.

Newly-hatched lightbrown apple moth caterpillars are tiny (less than 2 mm), with a pale yellow-green body and a pale-brown head. They wander actively over plant surfaces and may suspend themselves from a fine-silken thread until they find a suitable feeding site. The larvae prefer the underside of leaves and usually start to feed near a vein, where they spin a protective cover of fine webbing. As they mature, the larvae feed and shelter between two leaves webbed together or on single leaves which have been rolled in at the sides and webbed. When disturbed, the larvae wriggle violently and move further into shelter or else drop to the ground.

Fully-grown caterpillars are about 10 to 15 mm long, with a head width of about 1.4 mm.

The larval period usually takes between six and eight weeks, although it may be as short as three weeks in warmer weather. Mature larvae pupate within the feeding shelter. Newly-formed pupae are soft and green but harden and turn brown with age. The pupal stage lasts from one to four weeks depending on the surrounding temperature.

Resting moths are about 10 mm long and generally yellowish-brown with darker markings on the forewings. Female moths often have a dark spot on the back edge of the forewing.

Female moths can lay up to 1 500 eggs each, but the average is about 300. Depending on the surrounding temperature, most eggs are laid (between 6 and 10 days after moth emergence) in masses on the upper surfaces of any smooth-leaved host plants where they take from five to more than 30 days to hatch.

During the day, moths shelter among the foliage and make short-erratic flights if they are disturbed. Maximum flight activity occurs from two to three hours after sunset, with a smaller peak from three to four hours after sunrise. Flight is also affected by the phases of the moon, with peak activity shortly before and after a new moon and around a full moon.

Moths are present throughout the year but there are distinct peaks in September-November, October-December, and January-April.


Painted apple moth (Teia anartoides)
Larvae eat or skeletonise roses and a wide variety of other plants including Acacia, Melaleuca, Callistemon, Grevillea, fruit trees, pelargoniums and berry bushes. They are active throughout the year but may be more obvious during winter because the larval stage takes longer to complete.

Newly-hatched caterpillars are nearly black and turn brown as they mature. Fully grown caterpillars are about 45 mm long, and have a thick covering of long hairs and two red 'pimples' sticking out from the back, near the tail. The head is dull reddish-brown and lightly covered with long-greyish hairs, with a tuft sticking out from either side just behind the head. The thoracic segments (parts between the head and the abdomen) are marked with yellow and the first four abdominal segments have a brush-like bunch of greyish hairs in the centre of the back. Fully-grown larvae spin a flimsy light-brown silken cocoon through which the pupa can be seen. Female pupae are about twice the size of the male pupae which are about 15 mm in length.

Male moths have a wingspan of about 25 mm. The forewings are dark-brown with yellow and grey markings and a dark band. Hindwings are orange-yellow in the centre, with a broad black band encircling them, and fringed on the outer edge with yellow.

Female moths are wingless, thickly covered with short brown hairs, and have rudimentary antennae and legs. Each female can lay up to 700 glossy white, almost-spherical eggs on and around the cocoon. Female moths remain near the cocoon after emerging from the pupal case.

Sucking insects

Cottonycushion scale (Icerya purchasi)
This native insect infests roses, Acacia, Pittosporum, Grevillea, and many other plant species.

Newly-hatched nymphs (immature stages or crawlers) settle along the mid-veins on the undersides of leaves, but older nymphs migrate to the stems. The abundant honeydew secreted by scale insects is attractive to ants which often transport young scale onto new plants.

Mature females are red-brown, about 5 mm long and have an ovisac (about 10 mm long) beneath the body. The ovisac is a soft-cushiony mass which has a white-fluted surface and contains around 1 000 oval-red eggs.

California red scale (Aonidiella aurantii)
As well as infesting roses, these scale insects are a serious pest of citrus fruit and they infest a wide range of ornamentals. They inject a toxic saliva as they feed and cause leaf-yellowing, leaf-fall, and die-back of twigs and stems.

Female red scale are circular, about 2.5 mm in diameter and have a slightly raised centre. The scale is reddish brown, and the insect under the scale is yellow. Nymphs are light-yellow, oval, and less than 0.5 mm long. They emerge from under the female scale and crawl about for a few hours before settling permanently.

Scale numbers build up quickly in dry-dusty areas or dry seasons.


Rose aphid (Macrosiphum rosae)
The rose aphid is the most common of aphids that attack roses. The colour of this aphid ranges from green to reddish-green. Unfortunately, it lacks any other distinctive characteristics which make identification easy.

Aphids feed on roses by puncturing and sucking plant fluids from the veins. Aphids cause damage by secreting large amounts of honeydew which collects on leaves and buds. Honeydew encourages the growth of sooty mould which is unsightly and inhibits photosynthesis by reducing the amount of light reaching the leaves.

Only pregnant females survive over winter. In spring, females reproduce without mating and produce nymphs which form social broods and feed near their mothers.
Winged females develop and disperse and aphid populations build up rapidly with spring growth.


Rose scale (Aulacaspis rosae)
Heavy populations of rose scale reduce bloom production, new-shoot growth, and the response to bloom picking. Neglected bushes may die.

This scale is a hard or armoured scale which is mostly found on stems and branches of roses, raspberries, loganberries, and blackberries. Adult females are white or grey-white, flat and roughly 2.0 - 2.5 mm in diameter. There are two forms of adult males, sedentary and winged. Sedentary adult males are 0.8 x 0.3 mm long, flat, white and distinctly ribbed. Winged adult males are slightly smaller and orange-red with a distinct spine sticking out from the rear.

Females live for up to one year and lay one batch of around 40 eggs and sometimes a second batch after that. Pale-red nymphs or crawlers appear in spring and infest new growth by permanently attaching themselves to the plant and secreting their protective outer covering (scale). Females have two pre-adult stages. Males have four stages and become tiny two-winged insects. Cast scales, resulting from changing stages, stay as part of the adult.


Twospotted mite (Tetranychus urticae)
Roses are damaged when nymphs and adults pierce the leaves and suck the contents of cells causing them to collapse and die. Heavily-infested leaves become lifeless and may become bronzed and shrivelled. Plants may lose their leaves.

Females lay up to six eggs a day, totalling 70 or more. Eggs are minute, globular and almost transparent pale yellow-white. Males develop from unfertilised eggs and females develop from fertilised eggs. Egg hatch takes from three to 10 days depending on the surrounding temperature.

Newly-hatched larvae have six legs and are pale yellow-white, minute and oval. When they moult, larvae become eight-legged nymphs which mature after another two moults. Young mites take four to 12 days to mature and live for about three weeks.

In hot weather, the complete life cycle may be as short as two weeks and overlapping generations may occur.

Adult females are about 0.5 mm long and adult males are about 0.3 mm long. When feeding in summer, adult females are a yellowish-green with two pronounced dark spots, one on each side of the body. In males, these spots are less obvious and the body is smaller and tapered towards the rear. Both sexes also have two reddish eye-spots on the body.

Twospotted mite is a profuse web-spinner in its active stages.

Under artificial long-day length or in warm situations, such as glasshouses, twospotted mite may continue to feed and reproduce through winter. Outdoors, when temperatures and day length decrease in autumn, males die and adult females stop feeding and change colour to orange-red. They usually migrate to sheltered sites where they assemble over winter. When temperatures increase in spring, females leave their shelters, begin to feed, and lose their red colour.


Rasping insects

Plague thrips (Thrips imaginis)
Thrips have tubular mouthparts which cannot penetrate deep into plant tissue, so they usually feed on soft-recent growth or flowers by rasping or scraping surface cells and sucking the cell contents. This causes flowers to turn brown and shrivel. Normal opening of flowers may be affected if thrips enter unopened flowers. Egg-laying in young tissue may cause the tissue around the eggs to die and fall out, leaving small, irregularly-shaped 'shot-holes'. Some crops may be downgraded because of thrips faeces.

Colourless eggs are inserted into petal tissue, sepals, blossom stems, stamens, pistils, calyx cups and young leaves.

Nymphs feed on the stamens, pistils and petals. When fully grown, they crawl to the ground and pupate about 50 mm under the surface. Generation times vary from 10 days to more than a month depending on the surrounding temperature.

Adult females are narrow-bodied, light-brown or grey and 1-2 mm long. Males are smaller and yellow. Both sexes have two pairs of narrow-delicate wings which are fringed with long hairs and lie along the back when not in use.


Western Flower Thrips (Frankliniella occidentalis)
Western Flower Thrips (WFT) are transported in horticultural produce and are an insect pest of many ornamental, fruit, and vegetable crops.

WFT has been found in all Australian States, except the Northern Territory. This major insect pest is responsible for millions of dollars worth of crop damage world-wide due to its resistance to many insecticides and efficiency at spreading tomato spotted wilt virus.

WFT usually live and feed on flowers or new plant growth, such as buds and young leaves. Damage is not always obvious after feeding but becomes more obvious as the affected flowers, leaves or fruit grow and distort.

The WFT life cycle is mostly continuous and all stages of thrips can be found throughout the year. Female thrips live for 30 to 45 days and can produce around 150 to 300 eggs.

Diagnosis can be difficult because WFT looks similar to common onion and tomato thrips, however, experts from the Institute for Horticultural Development’s, diagnostic centre at Knoxfield can identify thrips specimens and give you advice.


Chemical control

Chemicals registered for use against major rose pests may not be registered specifically for roses but may be registered under "ornamentals." Remember, you are responsible for ensuring that the product you are using is registered for the purpose you are using it for.