Important Pests of Citrus in Asia
White-Spotted Longicorn Beetle (Anoplophora Macularia (Thomson))
Distribution
Widely distributed in China, Japan, Korea, Taiwan.
Description
The larvae of this beetle is a white grub with a dark brown or black head. Most of the damage to citrus trees is done by the larvae rather than the adult beetles.
The adult is black and shiny. It is a large, conspicuous insect with very long antennae ("feelers") (Fig. 1). The antennae of the males are 2.5 times their body length. The antennae of the female beetles are 1.3 times their body length.
Damage
Adult females lay their eggs in cracks at the base of the tree. The eggs hatch after about ten days, and the larvae immediately bore into the wood (Fig. 2). The holes and tunnels made in the wood by the larvae cause tree decline, and eventually wilting. Weakened branches may break off.
Furthermore, moisture and disease-causing fungi can enter through the damaged parts of the tree. Infested trees are thus prone to secondary attack by other insects, or by diseases.
The larvae cannot be seen since they are inside the wood, but sawdust and debris may be seen around the base of an infested tree. Egg-laying cavities eaten out by the females are found in the bark, and at the junction of branches and the trunk.
Life Cycle
The typical life cycle for this pest is:
Egg —> Larva —> Pupa —> Adult
The beetle can overwinter as an egg, a larva or a pupa. Adult beetles begin to emerge in the early summer months through small holes in the bark. Peak populations are found in the middle of summer. Females live 14-66 days, males live 3-50 days.
Citrus Stinkbug (=Shield Bug) (Rhynchocoris Humeralis Thunberg)
Distribution
Widely distributed in Southeast Asia.
Description
The citrus stinkbug is bright green and broadly oval in outline. The adult female is around 1.5 cm in length, while the adult male is smaller.
Stinkbugs are named for their ability to exude a stinking substance from a pore on each side of their body. They can also be recognized by the distinctive triangular shape of their bodies. The adult has a prominent spine on each shoulder of the thorax. Because their backs are shaped like a shield, stink bugs are sometimes given the name of "shield bugs".
Damage
The mouth of the stinkbug is like a long, pointed beak. Citrus stinkbugs feed on plant fluids by inserting their mouthparts into the stems, leaves and fruit. This damages the leaves and fruit, rather as if they have been stabbed repeatedly by a fine needle (Fig. 3).
Both the adults and nymphs of this bug suck the juices from young citrus shoots and fruit, especially at night. Young shoots become mottled and their growth is retarded. Feeding by stinkbugs often causes premature color break and fruit drop, as well as providing access for various fungal diseases and insects. Fruits which have been attacked show brown patches on the skin. These discolored patches make the fruit difficult to market.
The stinkbug is most destructive to satsumas, tangerines, and early and midseason oranges. Stinkbug damage is seldom seen on grapefruit or Valencia oranges, because of their thicker rind.
Life Cycle
The typical life cycle for this pest is shown below:
Egg —> Nymph
—> 1st Instar Larva —>
2/3/4th Instar Larva —> Adult
The female deposits her eggs on the leaves in clusters of 9 to 14 eggs (Fig. 4). The eggs hatch out after about one week.
The young nymphs remain clustered together for a short period of time and then start feeding on the young shoots and fruits. They pass through five nymphal stages and become adults after about 6 to 8 weeks.
Citrus Thrips (Scirtothrips Dorsalis Hood)
Distribution
Widely distributed in Southeast Asia.
Description
Thrips are very small, slender insects, less than 0.1 cm long (Fig. 5). Adult thrips have two pairs of narrow wings which are fringed with hairs.
Damage
Thrips feed by puncturing their host plant and sucking up the plant juices. They prefer to feed on young plant tissue, such as shoots, blossoms and young fruit. On fruit, they like to feed in protected areas such as under the calyx.
Citrus thrips, particularly the immature thrips, feed on the rind of the fruit and cause scarring (Fig. 6). A typical pattern is a ring of scarring at the stem end of the fruit. Second instar thrips damage the rind by piercing and sucking juices from the surface cells. Adult thrips do not harm the crop.
In addition to feeding on developing fruit, thrips also feed on the young shoots (Fig. 7, Fig. 8). Although this does not reduce the yields of mature trees, it will often delay the maturity of young trees which are not yet bearing fruit.
Life Cycle
The typical life cycle for this pest is shown below:
Egg —> 1st Instar Larva
—> 2nd Instar Larva
—> Propupa —>Pupa —> Adult
Eggs are deposited in plant tissue. Hatching occurs over about five days during the summer months. The immature stages take around five to seven days to complete their development.
Aphids
About Aphids
Aphids are very small insects about 2 mm long. Some aphids are found only on specific hosts. The citrus aphid, for example, is almost always found on citrus trees. A few species of aphid, such as the cotton aphid, are found on a wide range of crops and also on weeds.
Both the adults and nymphs of these pests suck the sap from the young shoots, causing them to curl up and become yellow in color. As a result growth of the shoots is greatly impaired and the shoots are often distorted. The aphids also produce a sticky liquid on which sooty mold grows. This looks like a thin coating of black powder on the leaves, shoots and fruit.
However, the important damage inflicted by aphids is indirect. Aphids, particularly the citrus aphid, are the main vectors of citrus tristeza virus. Tristeza virus is one of the most important citrus diseases in Southeast Asia (see page 59). The aphids spread the virus by sucking the sap of an infected tree, and moving on to a healthy one, taking the virus with it.
Life Cycle
Aphids do not lay eggs, but produce live young. The life cycle, from the birth of the young aphids through numerous molts to the adult form, may be as short as one week. The adult aphid has both a winged and a wingless form (Fig. 9, Fig. 10). Winged forms are born when crowding occurs, to enable populations to disperse.
The typical life cycle for this pest is: Nymph —> Adult
Citrus Aphid (Toxoptera Citricida (Kirkaldy))
Also called the brown aphid, the brown citrus aphid, or the tropical citrus aphid.
Distribution
Worldwide distribution. The citrus aphid is especially common and noxious in subtropical and tropical areas.
Description
Citrus aphids are black, and are slightly larger than the other aphids which feed on citrus. They are often found in dense, dark populations on the young shoots of citrus trees (Fig. 11).
They do not attack older leaves. The immature stages are reddish-brown in color.
Green Citrus Aphid (Aphis Citricola Van Der Geet) Also Called the Spirea Aphid
Distribution
Worldwide distribution.
Description
The adult green citrus aphid is apple-green in color, and about
2 mm long (Fig. 12).
Cotton Aphid (Aphis Gossypii Glover)
Also called the melon aphid
Distribution
Worldwide distribution, in tropical, subtropical and temperate zones.
Description
The cotton aphid is smaller than most other aphid species. It is generally a greenish color, but the color can range from yellowish green to dark blue-green (Fig. 14, Fig. 15). It has a wide host range, and is a pest of melon, cotton, tomato, asparagus and many other crops, as well as being found on a wide range of weeds. This aphid transmits more than 80 kinds of virus disease to various crops, including the infection of citrus trees with citrus tristeza virus.(Fig. 13).
Asian Citrus Psyllid (Diaphorina Citri Kuwayama)
Distribution
This aphid is widely distributed in tropical and subtropical Asia. It is cold-sensitive, and is not found in areas where minimum winter temperatures fall below 15oC. Another psyllid, the African citrus psyllid, is cold tolerant but is not found in Asia.
Life Cycle
The typical life cycle for this pest is: Egg —> Nymph—> Adult
Description
This tiny insect is 3-4 mm long, mottled brown in color, with transparent wings. The eggs of psyllids are bright yellow and deposited on young leaves. Nymphs (immature psyllids) are green or dull orange, and can be difficult to see because they blend in with the leaf.
The Asian citrus psyllid is most likely to be found on new shoots (Fig. 16). For this reason, their numbers tend to increase when new leaves are sprouting. This is likely to be at the beginning of spring, when the weather warms up after a cool winter, or at the beginning of the rainy season.
Flushes of new growth may occur several times a year in some areas. The Asian citrus psyllid cannot withstand low winter temperatures and is not found in Korea and Japan, which consequently are both free of greening disease.
Damage
Psyllids reproduce quickly, and large populations can damage trees when they feed on them
(Fig. 17). Psyllid feeding causes curled, distorted leaves and premature leaf drop. However, it is the greening disease transmitted by the psyllids which does most damage to the region's citrus orchards. Greening is the most important disease of citrus trees in tropical and subtropical Asian countries.
The psyllid acquires the greening organism when it feeds on the sap of an infected tree, and carries it in its mouth parts when it moves onto a healthy one. The ability of the psyllid to transmit greening disease varies from one place to another, depending on the biotype of the psyllid. The Taiwan biotype, for example, has a very low transmission rate of less than 1%.
However, field transmission of the pathogen by the psyllid vector is significant, since it is very difficult to keep trees completely free of psyllids. This means that citrus trees may be exposed to infection in the open for quite a long time.
Mealy Bugs
About Mealybugs
Mealybugs are slow-moving insects with flat, oval bodies. They are covered with a thin layer of white wax, and look as if they have been rolled in white flour, hence their name of "mealybug". They often crowd together in colonies on a sheltered part of the plant.
They feed on sap, using their sucking mouthparts. Their saliva is toxic to plants, and heavy infestations may cause distorted growth and premature leaf drop. Like aphids, mealybugs excrete a sugary syrup known as honeydew. This serves as a food source for sooty mold fungus, which grows on the honeydew.
Life Cycle
The life cycle of this pest is different in males and females. Males go through an additional stage.
Egg —> crawler (=1st instar) —> 2nd/3rd/instar nymph (which looks like the adult) —> adult female
Egg —> crawler —> 2nd/3rd/instar —> male pupa (=cocoon)
—> adult male
Citrus Mealybug (Planococcus Citri Risso)
The adult citrus mealybug is 3-4 mm long (Fig. 18). Up to 500 yellow eggs are laid in a dense waxy white sac. The eggs hatch in a few days into tiny, mobile yellow crawlers with red eyes. The crawlers move onto the fruit and leaves. Later stages may migrate down the trunk and reproduce on weeds. Citrus mealybugs can live on many plants besides citrus. They often live in green-houses on ornamental crops.
Citrus mealybugs damage plants by sucking their sap. Fruit infested with citrus mealybug also show damage (Fig. 19). However, the most important economic damage from mealybugs is caused by the black sooty mold, which disfigures the fruit and reduces their market value.
Spherical Mealybug (Nipaecoccus Filamentosus (Cockerell))
The adult female spherical mealybug is 2.5-4 mm long, slightly flattened in shape, and covered with creamy white wax. Beneath the wax, the body is a purplish color. The adult female is usually almost hidden by her large white domed egg sac (Fig. 20).
Spherical mealybugs infest a number of other important fruit crops besides citrus, including mango, papaya and grape.
Scales
About Scales
Scale insects are small insects which suck the sap of plants. Usually, they have some kind of protective covering over their bodies. Soft-scale insects have a toughened skin on the upper surface of their bodies. Hard scale are very small, and are covered by a waxy shield like armor. They are sometimes called "armored scale".
Young scale crawlers are mobile. Adult females have no wings, and usually remain fixed in one place. If they move at all, they are very sluggish.
All citrus scales described in this chapter, both soft scale and hard scale, also infest a range of other plants, particularly tree crops and ornamental crops. For example, Green scale infests a wide range of plants as well as citrus, including coffee and vegetable and ornamental crops.
Life Cycle:
The life cycle of this pest is:
Egg —> crawler (=1st instar nymph) —> 2nd/3rd instar nymph —> adult
I. SOFT SCALES
Green Scale (Coccus Viridis Green)
Distribution
Widely distributed in the tropics.
Description
The adult female is a pale yellowish green. It is oval in shape, and 3-5 mm long. It can be distinguished by the black
U-shape of its gut. Although the gut is internal, this marking can be seen from above by the naked eye.
The female green scale reproduces without mating. Eggs are whitish green, elongate-oval and are laid singly. They may hatch as soon as they are laid, or a few hours later. Crawlers (1st instar nymphs) emerge and move out over the citrus tree. Once a suitable leaf or green shoot is found, the crawlers settle and begin to feed. They usually remain in this same spot unless their position becomes unfavorable. The mature female does not move (Fig. 21).
Green scale are found mainly on young leaves and green twigs of the tree. If there is a heavy infestation, they may also be found on the fruit.
Green scale insects are often found together with ants which feed on their honeydew.
Damage
Green scale are usually found on the undersurface of the leaf, often in a line along both sides of the midrib and lateral leaf veins (Fig. 22). Green scale may also attack the young shoots, which may become almost hidden in a mass of scales.
Large populations of green scale may cause yellowing, defoliation, reduction in fruit set and loss of plant vigor. Citrus scale is especially damaging to young trees in the first two years after transplanting. Economic damage is also caused by the sooty mold, which disfigures the fruit and reduces photosynthesis when it occurs on leaves.
Cottony-Cushion Scale (Icerya Purchasi (Maskell))
Distribution
World-wide distribution.
Description
The body of the female cottony- cushion scale is orange, red, yellow or brown. However, it is most easily recognized by the fluted, cottony white egg sac that is attached to its body (Fig. 23). The egg sac contains from 600 to 800 red eggs, and is usually found on twigs. The egg sac may become two or three times longer than the body of the female, resulting in an overall length of around 1 cm.
Crawlers are red with black legs. The second- and third-instar nymphs are covered with a whitish, cottony substance which disappears after the insect molts. Unlike most other scales, the cottony-cushion scale retains its legs and remains mobile throughout its life.
Damage
Like other scales, the cottony cushion scale sucks the sap from the leaves and twigs, thus reducing the yield. Heavy infestations are uncommon, but if they occur, can result in defoliation and dieback of twigs (Fig. 24). The cottony cushion scale excretes honeydew, which is often accompanied by sooty mold growth and ants.
II. Hard scales
Florida Red Scale (Chrysomphalus Aonidum (Linnaeus)) Distribution
Widespread in Central and South America, Europe and Asia. Particularly common and noxious in tropical countries.
Description
The adult female is small and round, about 2 mm across. It is a dark reddish-brown in color (Fig. 25). The adult male is oval and about half the size of the female. The Florida red scale, like other hard scale, does not produce any honeydew, so it is not found together with sooty mold and ants.
Hard scales are also known as "armored scales". The scale or armor is made from a thin, hard waxy cover. The females lay up to 300 eggs. When the crawlers hatch, they settle close to the mother scale on leaves and fruit (Fig. 26).
Purple Scale (Lepidosaphes Beckii (Newman)) Also Called the Mussel Scale
Distribution
World-wide distribution.
Description
The hard cover of the adult female is brownish purple in color, elongated and shaped a little like a comma (Fig. 27). The cover of the male is similar in color to that of the female, but is shorter and narrower. The female lays a mass of 50-100 pearly white eggs under their own scale cover. The eggs hatch after a few weeks. The crawlers are very small, less than 0.25 mm, and are pearly white in color. Three or more generations may occur each year. Unlike soft scales, the purple scale does not produce honeydew.
Purple scales infest citrus leaves, fruit and bark. They prefer sheltered and shady parts of the tree. They may occur singly, or in scattered clumps. Like the other scales, purple scales suck the sap, and cause further damage by injecting toxins into the host plant while feeding.
Places where they have been feeding may show yellow or brown areas around the feeding site, followed by leaf and fruit drop. Green spots may show on ripe fruit where scales were present, thus reducing the market value.
Chaff Scale (Parlatoria Pergandii Comstock)
Distribution
Worldwide distribution.
Description
The scale of the adult female is an irregular oval shape, and light yellowish brown in color (Fig. 28). The males are slightly smaller than the females. The male scale is white, and almost oblong in shape. The body under the scale is purplish in color.
The chaff scale often occurs together with Florida red scale and purple scale on the same tree. It is most common on the tree trunk and main branches, but also infests the leaves and fruit (Fig. 29, Fig. 30).
Moths and Butterflies
Many kinds of moths and butterflies are found on citrus trees. Generally speaking, the trees are not damaged by the adult butterflies and moths. The damage is caused by the larvae when they feed on the leaves.
The typical life cycle for this pest is:
Egg —> Larva (=caterpillar)
—> Pupa (=cocoon)
—> Adult (moth or butterfly)
Citrus Leafminer (Phyllocnistis Citrella Stainton)
Distribution
Widely distributed worldwide, including temperate, subtropical and tropical Southeast Asia. This pest is found only on citrus trees.
Description
The citrus leafminer is a small, delicate moth about 2 mm long. It is brownish-grey in color, with hindwings fringed with long hairs. Because adults are nocturnal, they are seldom seen. They may sometimes fly out when foliage is disturbed.
Eggs are laid singly on the underside of leaves near the midrib. The eggs are about 0.3 mm across, and look like tiny water droplets. They hatch within 3-5 days. The young larvae immediately start burrowing under the surface of the leaf. They pupate, when full grown, near the margin of the mined leaf. The total life cycle is about 2 - 3 weeks.
Damage
The characteristic damage from leafminer is silvery or yellowish `blisters' or wavy lines on the surface of the leaf (Fig. 31, Fig. 32). This is produced by the larvae, which tunnel or mine through the leaf, following a characteristic wavy path just below the leaf surface (Fig. 33). Each larva has its own tunnel. Larvae never leave their mines to make new mines, or move into the upper surface of the leaf. Usually each leaf has only a single mine, but in cases of heavy infestation there may be several mines per leaf. This mining of the leaves causes them to curl up and look distorted (Fig. 34). Sometimes leafminers may attack the young shoots and cause them to wilt.
Citrus Leafroller (Homona Coffearia Nietner)
Distribution
The citrus leafroller is wide-spread in Asia, from India to Japan. It is found on other crops beside citrus, including coffee and indigo, and is an important pest of tea. When the same species of leafroller is found on tea, it is generally known as the tea tortrix.
Description
The adult citrus leafroller is a small brown moth, with curved wings which bear black spots. The larvae are slender and green, with a dark head (Fig. 35). Adult moths are active during the night, and shelter in the tree during the day. The pale green eggs are laid singly, usually on the upper surface of the leaf near the midrib.
The newly hatched larvae spin a thin silk web on the leaf surface, and stay beneath it to feed. As the larvae grow, they begin to fold or roll the leaf longitudinally and feed within the roll. From time to time they move to new sites and make a new leaf roll. When the larvae are mature, they pupate inside a cocoon inside the leaf roll (Fig. 36).
Damage
Damage is mainly from the loss of young leaves, which reduces photosynthesis and depresses the yield.
Oriental Fruit FLY (Bactrocera Dorsalis Hendel)
Distribution
The Oriental fruit fly is widespread in tropical Asian countries. where fruit fly is found.
Description
The Oriental fruit fly infests guava, mango, papaya and many other kinds of fruit besides citrus. To some extent, citrus fruit are protected from fruitfly attack by their thick skins. Oriental fruit fly tends to attack citrus fruit only when the fruit are ripe.
The adult fruit fly is around 8 mm long, larger than an ordinary housefly. The color of the fly varies, but there are always yellow and dark brown markings on the thorax (Fig. 37).
The larvae are small white maggots, and are 7-11 mm long. The adults mate at dusk, and the female lays its egg just inside the skin of a fruit. Under optimum conditions, a female can lay more than 3,000 eggs during
her lifetime.
The egg hatches into a larva which then burrows into the fruit (Fig. 38). The mature larva emerges from the fruit, drops to the ground, and forms a brown pupa about 5 mm in length.
Damage
It is the larvae of this pest which causes damage, rather than the adult fruit flies. They burrow through the fruit, making it unfit for human consumption.
Fruit fly is economically the most important insect pest of fruit in Southeast Asia, and can cause losses of 90-100%.
It can also prevent the development of export markets. Countries which do not have fruit fly are anxious to remain free of the pest.
They usually impose strong quarantine restrictions on imports of fruit from countries where fruit fly is found.
Mites
About Mites
Mites are not insects, they belong to a different group. They are very small, less than 1mm long, and are quite difficult to see with the naked eye. To see them in any detail, you need a magnifying glass of some kind. Nymphs and adults have four pairs of legs. Larvae have only three pairs of legs.
There are a wide range of mite species which live on citrus trees. Many of them are pests which attack the leaves and fruits. They have piercing and sucking mouth parts which suck the sap. Their feeding scars the fruit, reducing its market value, and causes discoloring and distortion of buds and leaves.
However, not all mites are pests. Some species of mites are beneficial to growers, because they prey on pest mites, while they themselves do no damage to the plants.
It takes an expert to distinguish the two kinds. In any case, the beneficial mites will be killed along with the pest species of mites when they are sprayed.
Life Cycle
The typical life cycle for this pest is:
Egg —> Larva —> Protonymph —> Deutonymph —>
Adult
The larvae and nymphs (protonymphs and deutonymphs) resemble the adults, except that they are smaller and the larvae only have three pairs of legs.
Citrus Rust Mite (Phyllocoptruta Oleivora (Ashmead))
Distribution
A serious pest worldwide, especially in the humid areas. This mite is found only on citrus trees.
Description
The citrus rust mite infests twigs, leaves, and fruit of all kinds of citrus. It particularly prefers lemons and grapefruit. The mite has an elongated, wedge-shaped body, with the head at the broader end. It is pale yellow in color. However, the body is so small (0.1 mm long) that it is difficult to see without a magnifying glass.
The female begins laying eggs as soon as she reaches maturity, and continues laying 1-2 eggs per day as long as she lives. The eggs are about a quarter the size of the adult mite. The eggs are spherical, ranging in color from transparent to pale translucent yellow.
Mite populations usually begin to build up when new growth appears. The mites move on to the new flushes, and then on to the fruit as they appear. Early in the season, most citrus rust mites are found on new leaves. Later in the season, higher populations are found on the fruit. Generally, populations are highest in the lower branches of the tree. The mites tend to prefer the sheltered side of the citrus tree, away from direct sunlight.
Damage
Citrus rust mites feed with their sucking-piercing mouth parts just below the skin of the leaves and fruit. This turns the green twigs and mature leaves a reddish brown color, known as "russeting".
Most of the leaf damage occurs when the mites feed on the undersurface of the leaf (Fig. 39). This causes "bronzing", and interferes with photo-synthesis. Extensive damage to the lower leaf can result in leaf drop, especially in dry or cold weather.
However, it is the injury to the fruit which causes the greatest economic damage. Injuries from feeding mites produces blemishes on the peel of the fruit, which reduces the market value. Damage varies according to the type of citrus fruit and its maturity.
Citrus rust mites seem to prefer to feed on immature fruit. Injury to lemons when the fruit are very small causes discoloration of the peel, which may be severe. The skin has a thick, grey to dirty brown appearance known as "shark skin".
Injury to young orange, mandarins and grapefruit produces a greyish-brown discoloration or silver-grey blemish on the surface of the fruit (Fig. 40). Heavy infestations may even turn the skin black.
If citrus fruit are attacked when they are fully grown, mite damage shows as a brown stain on the peel surface. This late injury on the fruit is referred to as "bronzing" (Fig. 41).
Damage to fruit from heavy mite infestation can sometimes be confused with that caused by melanose, chemical burn or weather staining. However, mite damage tends to be found on the surface of the fruit facing inside the tree. Damage from weather etc. tends to be on the exposed, outer surfaces of the fruit.
Growers who suspect mite infestations are causing the discoloration should also look for the tiny white skins on the fruit which are shed by the nymphs of the mites when they molt.
In addition to the visible symptoms, citrus fruit attacked by rust mites has a slower growth rate, so that the average size at harvest may be smaller. There is also a higher rate of fruit drop.
Citrus Red Spider Mite (Panonychus Citri Mcgregor) (Also Called Citrus Red Mite)
Distribution
The citrus red mite is native to Asia, but now has a world-wide distribution. It is found on other plants besides citrus, including mulberry and some legumes.
Description
The adult citrus red mite has an oval body which is dark red in color (Fig. 42, Fig. 43).
Damage
The citrus red mite feeds on leaves, green twigs and fruit, but prefers the fully expanded leaf.
Most damage occurs on the upper surface of the leaf. A pale stippling is seen, which in cases of severe infestations enlarges to dry necrotic areas. Marks are also seen on the underside of the leaves (Fig. 44).
Stippling or silvering also occurs on green fruit but these often disappear when the fruit change color. Damaged mature oranges and lemons may become pale yellow in color. Severe infestations result in fruit drop and leaf drop. Citrus red mite is likely to be more of a problem in hot, dry weather, especially if the trees are suffering from water stress. Populations of citrus red spider mite tend to be heavier in orchards where natural enemies have been destroyed by the use of broad-spectrum insecticides such as methidathion and dimethoate.
Index of Images
Figure 1 Adult White-Spotted Longicorn Beetle
Figure 2 Larva of White-Spotted Longicorn Beetle Tunneling through Wood of Citrus Tree
Figure 3 Adult and NYMPH Stink Bugs on Citrus
Figure 4 Eggs of Stink Bug
Figure 5 Adult Thrips (Magnified)
Figure 6 Scarring on Fruit Caused by Feeding by Thrips
Figure 7 Damage to Leaves from Citrus Thrips
Figure 8 Young Shoot Damaged by Thrips
Figure 9 Citrus Aphid: Winged (= Alate) Form
Figure 10 Citrus Aphid: Wingless (= Apterous) Form
Figure 11 Heavy Infestation of Citrus Aphids
Figure 12 Green Citrus Aphid
Figure 13 Citrus Leaves Infested with Cotton Aphids
Figure 14 Cotton Aphid: Apterous Form (without Wings)
Figure 15 Cotton Aphid: Alate or Winged Form
Figure 16 Citrus Psyllids
Figure 17 Heavy Infestation of Citrus Psyllids
Figure 18 Citrus Mealybug
Figure 19 Fruit Damaged by Mealybug
Figure 20 Spherical Mealybug
Figure 21 Citrus Green Scale and Parasitized Citrus Green Scales.
Figure 22 Leaf Damaged by Green Scale
Figure 23 Cottony-Cushion Scale
Figure 24 Cottony-Cushion Scale on Citrus Tree
Figure 25 Florida Red Scale
Figure 26 Damage to Fruit from Florida Red Scale
Figure 27 Purple Scale (Magnified)
Figure 28 Chaff Scale (Magnified)
Figure 29 Examples of Fruit Damaged by Chaff Scale.
Figure 30 Examples of Fruit Damaged by Chaff Scale.
Figure 31 Larva of Leafminer (Magnified) Inside Citrus Leaf
Figure 32 Damage to Citrus Leaves from Leafminer
Figure 33 Damage to Citrus Leaves from Leafminer
Figure 34 Damage to Citrus Leaves from Leafminer
Figure 35 Larva (Caterpillar) of Leafroller and Damage to Leaf
Figure 36 Pupa (Cocoon) of Leafroller on Citrus
Figure 37 Adult Oriental Fruit FLY
Figure 38 Guava Infested with Fruitfly Larvae
Figure 39 Damage to Leaves from Citrus Rust Mite
Figure 40 Damage to Pomelo Fruit from Citrus Rust Mite
Figure 41 Damage to Sweet Orange Fruit from Citrus Rust Mite
Figure 42 Male Red Spider Mite (Magnified)
Figure 43 Female Red Spider Mite (Magnified)
Figure 44 Two Leaves, Seen from underneath. the Leaf on the Left Is Damaged by Red Spider Mite. the Leaf on the Right Is Normal.
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