Study the official Citrus identification pool from real references first, then compare illustrations and approved supplemental sketches without changing the official answer bank.
Look for raised corky lesions with a distinct yellow halo on leaves, twigs or fruit.
Canker = corky crater + yellow halo.
Look for a tiny mottled brown wedge-shaped adult feeding with its rear end raised at about a 45-degree angle; nymphs are yellow-orange on new flush.
ACP = tiny wedge feeding tail-up.
Start with the trifoliate leaf: three leaflets on one petiole, often with a noticeable winged petiole.
Carrizo = trifoliate citrus hybrid; confirm the whole sample.
Look for relatively narrow mandarin-type leaves and small orange mandarin-like fruit on this rootstock type.
Cleopatra = mandarin-type single leaf, not trifoliate.
Look for unmistakable trifoliate leaves plus stout thorns; fruit is small, yellow and very seedy/bitter.
Trifoliata = three leaflets + thorny, hardy rootstock.
Look for a lemon-like rootstock fruit with a distinctly coarse, rough or pebbled rind.
Rough Lemon = the name is the rind clue.
Look for a noticeably flattened, orange-like fruit with a smoother rind than rough lemon.
Smooth Flat Seville = smooth + flattened orange form.
Look for an orange-like fruit and a leaf with a broad, obvious winged petiole.
Sour orange = broad petiole wing.
Start with trifoliate leaves, then look for the larger citrus-hybrid leaflets and strongly winged petiole.
Swingle = trifoliate rootstock; confirm the wings and fruit.
Look for a lemon/rootstock fruit that is usually rounder and smoother than rough lemon, often yellow-orange when mature.
Volkamer = smoother, rounder lemon-type rootstock.
Look for a large yellow lemon with an elongated oval shape and a noticeable nipple at the blossom end.
Bearss = big commercial lemon + pointed end.
Look for very small round orange fruit—much smaller than a typical mandarin.
Calamondin = tiny round orange.
First confirm the navel at the blossom end; when cut, the flesh is pink to red rather than standard orange.
Cara Cara = navel outside, pink-red flesh inside.
Look for a small, smooth, deep-orange mandarin with an easy-peel appearance.
Clementine = small smooth easy-peel mandarin.
Recognize grapefruit size first; when cut, Duncan is white-fleshed and notably seedy.
Duncan = white grapefruit + seeds.
Look for a large early-season mandarin with a deep orange-red rind and a broad, slightly flattened form.
Fallglo = large, bright early mandarin.
Confirm grapefruit size, then use the interior: Flame is a red-fleshed grapefruit with very few seeds.
Flame = red grapefruit + low seed count.
Look for a broad, relatively large citrus leaf with a conspicuously winged petiole.
Grapefruit leaf = big blade + big wing.
Look for a round sweet-orange fruit with a smooth thin rind and no navel.
Hamlin = plain round sweet orange, no navel.
Look for a small, round-to-oval lime with a thin rind; ripe fruit can turn yellow and is commonly seedy.
Key lime = small + thin rind + seeds.
Look for a very small orange citrus fruit, often oval, with a proportionally thick sweet peel.
Kumquat = tiny orange fruit, often oval.
Look for an elliptic leaf with little or no petiole wing and a slightly toothed margin; young growth may be reddish.
Lemon leaf = almost no wing.
Confirm grapefruit size, then use the inside: pale/white flesh with very few or no seeds.
Marsh = white grapefruit, seedless.
Look for the classic bell/pear shape with a pronounced neck at the stem end.
Minneola = HoneyBell neck.
Look for a medium, deep-orange, slightly flattened tangerine with a tighter peel than Satsuma.
Murcott = deep orange, tight-skinned honey tangerine.
Look for a medium oval citrus leaf with a narrow wing on the petiole.
Orange leaf = middle-size petiole wing.
Look for a round to slightly flattened tangelo, generally without the dramatic neck of Minneola.
Orlando = round tangelo.
Look for a tangelo leaf with a citrus-hybrid appearance and a noticeable winged petiole.
Orlando leaf = tangelo leaf + visible petiole wing.
Look for a larger oval lime, usually seedless, with a thicker rind than Key lime.
Persian = big seedless lime.
Look for a round midseason sweet orange with no navel; if cut, expect more seeds than many commercial sweet oranges.
Pineapple = sweet orange + seeded interior clue.
Look for the largest citrus fruit in the set, often round-to-pear-shaped with a very thick rind.
Pummelo = giant citrus + thick rind.
Confirm grapefruit size and inspect the cut flesh for a deep red color.
Ray Ruby = deep red grapefruit; don't trust rind alone.
Look for grapefruit size with pink-to-red flesh and a possible pink blush on the rind.
Ruby Red = classic red-fleshed grapefruit.
Look for a distinctly flattened mandarin with a loose, puffy, very easy-peel rind.
Satsuma = flat + loose jacket.
Look for a medium tangerine with a deep reddish-orange, smooth glossy rind and a somewhat flattened shape.
Sunburst = glossy deep-orange tangerine.
Look for a deep orange-red, round-to-slightly-flattened tangor with a somewhat pebbled rind.
Temple = pebbled deep-orange tangor.
Look for a medium broad citrus leaf with a visible but not grapefruit-sized petiole wing.
Temple leaf = medium-broad blade + moderate wing.
Look for a round-to-oval sweet orange with a thin smooth rind and no navel.
Valencia = smooth late orange, no navel.
Look for the secondary 'navel' structure at the blossom end of a seedless sweet orange.
Washington Navel = find the belly button.
Look for leaf chlorosis and tip/marginal scorch associated with fertilizer-grade urea containing too much biuret.
Biuret = urea injury + chlorosis/scorch.
Look for dieback, misshapen growth and coarse or gummy symptoms on shoots/fruit rather than a simple uniform yellow leaf.
Copper deficiency = dieback/deformed growth, not just yellow veins.
Look for herbicide injury expressed as irregular chlorotic or necrotic leaf areas rather than a tidy nutrient pattern.
Diuron injury = irregular chemical burn pattern.
Look for distorted, narrow or strap-like new growth with chlorosis after herbicide contact.
Glyphosate = distorted new growth after contact.
Look at the newest leaves: the tissue turns yellow while the veins remain sharply green.
Iron = young yellow leaf, green vein skeleton.
Look at older leaves for yellowing on both sides of the midrib that leaves a green inverted-V or arrowhead area near the base.
Magnesium = green arrowhead at leaf base.
Look for a light-green/yellow leaf with a network of greener veins, usually less sharply contrasted than iron deficiency.
Manganese = soft green-vein mottling.
Look for broadly uniform pale green-to-yellow foliage, commonly beginning on older leaves.
Nitrogen = overall pale yellow.
Look for brown necrotic tips and leaf margins, often with a sharp boundary between healthy and burned tissue.
Salt burn = crispy edges and tips.
Look for small, narrow leaves with interveinal yellow mottling and shortened internodes/rosetting.
Zinc = little leaf + mottling + rosette.
Look for dark brown necrotic lesions with yellow halos on young leaves and fruit, often with irregular expansion along veins.
Alternaria brown spot = flat brown lesion + yellow halo.
Look for dark leaf spots that may enlarge or merge and are often surrounded by yellow tissue.
Alternaria leaf spot = necrotic spot + yellowing.
Look for firm brown leathery fruit decay, often beginning on fruit low in the canopy after wet conditions.
Brown rot = brown leathery fruit.
Look for chronic decline with bark symptoms such as gum impregnation, pitting or discoloration in susceptible mandarin/tangelo tissues.
Cachexia = internal bark/gum/pitting decline.
Look for dark fruit lesions that can appear as hard spots, freckles or larger necrotic areas, often with contrasting orange/yellow tissue.
Black spot = multiple dark lesion types on fruit.
Look for an established tree with thinning canopy, wilt, twig dieback and chronic decline despite apparently adequate soil moisture.
Blight = mature tree wilts and thins.
Look for asymmetrical blotchy mottling that does not mirror across the leaf midrib; fruit may be lopsided or unevenly colored.
HLB = blotchy, uneven, asymmetric.
Look for raised corky, wart-like lesions that distort young leaves and fruit.
Scab = rough corky warts.
Look for scaling, shelling or cracking bark on susceptible rootstock tissue below the bud union, often with dwarfing.
Exocortis = bark scales below the graft.
Look at the trunk base for dark water-soaked bark, gum exudation, cracking and decay near the soil line.
Foot rot = gum and bark rot at the ground line.
Look for yellowish leaf spots above and dark, greasy-looking raised lesions on the underside of mature leaves.
Greasy spot = greasy underside lesions.
Look on grapefruit rind for numerous small dark specks or pits that can create a pink-pitted or rind-blotch appearance.
Rind blotch = many tiny rind pits/specks.
Look for postharvest fruit decay that starts soft/watery and quickly develops white mold followed by blue-green spores.
Green mold = white first, then blue-green spores.
Look for many tiny raised dark specks that feel like sandpaper; on fruit they may run in tear-stain streaks.
Melanose = sandpaper specks / tear stains.
Look for sharply defined translucent or water-soaked-looking patches between veins that later turn tan or necrotic.
Mesophyll collapse = patchy tissue collapse between veins.
Look for orange-brown lesions on flower petals followed by dropped young fruit and persistent enlarged green calyx 'buttons.'
PFD = petal lesions + leftover buttons.
Look for scaling/flaking bark on trunk or scaffold limbs; young leaves may show temporary flecking patterns.
Psorosis = scaly trunk/scaffold bark.
Look for brown decayed feeder roots together with a thinning, yellowing canopy and poor vigor.
Root rot = bad feeder roots + thinning top.
Look for a black soot-like coating on leaves or fruit that sits on the surface over insect honeydew.
Sooty mold = black surface soot from honeydew.
Look for very soft, watery postharvest fruit decay with a sour odor and pale fungal growth.
Sour rot = soft watery sour decay.
Look for decay beginning at the stem/button end and spreading downward through the fruit.
Stem-end rot = decay starts at the button.
Look for decline or quick decline on susceptible rootstocks; stem pitting and vein symptoms may occur in some hosts.
CTV = decline/stem pitting, especially with susceptible rootstock.
Look for superficial corky/russet scarring on fruit where leaves or twigs rubbed the rind during growth.
Wind scar = rub marks, not infection.
Look for bright red-orange or yellow cushion-like fungal growth on whitefly scale stages; it is a beneficial fungus.
Aschersonia = colored fungus attacking whiteflies.
Look for a dark brown-to-black domed oval scale with a characteristic raised H-like ridge on the back.
Black scale = dark dome + H ridge.
Look for a broad-snouted adult weevil covered with blue-green scales.
Blue-green weevil = blue-green scaled snout beetle.
Look for colonies of dark brown to nearly black soft-bodied aphids crowded on tender new flush.
Brown citrus aphid = dark aphids on flush.
Look for a yellow-brown fruit fly with patterned wings and a relatively long body/ovipositor in females.
Caribbean fruit fly = larger patterned fruit fly.
Look for dark slate-black nymphal scales on leaf undersides, often ringed with waxy fringe; adults are small dark whitefly-like insects.
Citrus blackfly = black whitefly-type scales.
Look for winding silvery serpentine mines in tender leaves, often causing curled or distorted new growth.
Leafminer = silver squiggle tunnel.
Look for soft-bodied insects covered in white cottony wax, often clustered in fruit/stem crevices.
Mealybug = little cottony clusters.
Look for a tiny mottled brown wedge-shaped adult feeding with its rear end raised at about a 45-degree angle; nymphs are yellow-orange on new flush.
ACP = tiny wedge feeding tail-up.
Look for very small bright red mites/eggs on leaves and fruit together with fine stippling or bronzing.
Red mite = red specks + stippling.
The mite itself is nearly microscopic; identify the bronze/russet rind or leaf surface damage it produces.
Rust mite = tiny mite, big bronzing clue.
Look for bark that appears dusted with snow from masses of elongated white male scales; darker females may be mixed in.
Snow scale = white snowstorm on bark.
Look for a brown-orange female attached to a large white ribbed/fluted cottony egg sac.
Cottony cushion = fluted white pillow.
Look for a large snout weevil with bold black-and-cream/yellow/orange striping or scale patterns.
Diaprepes = big colorful striped weevil.
Look for small round flattened reddish-brown scale covers on fruit, leaves or twigs, often with a central nipple.
Florida red scale = flat red-brown round disk.
Look for a gray-brown broad-snouted weevil with a rough/scaly body; leaf edges may show scalloped feeding.
Fuller's rose beetle = gray rough snout weevil.
Look for a long, very narrow brown mussel-shaped scale cover aligned along twigs/leaves.
Glover's = skinny brown mussel scale.
Look for the large jumping hind legs, chewing mouthparts and stout body of a grasshopper.
Grasshopper = power hind legs + shorter antennae.
Look for clusters of bright green soft-bodied pear-shaped aphids on tender shoots.
Green aphid = green soft colony on flush.
Look for evidence of the beneficial fungus on rust mites—infected tiny mites may appear coated or anchored by whitish fungal growth.
Hirsutella = fungus that attacks rust mites.
Look for a green leaf-like insect with extremely long threadlike antennae and strong jumping hind legs.
Katydid = green leaf body + very long antennae.
Look for an alligator-shaped predator larva often carrying bits of debris/prey remains on its back.
Trash bug = predator hiding under trash.
Look for a small dome-shaped beetle, often red/orange/yellow with contrasting spots or markings; larvae are elongated predators.
Lady beetle = little dome predator.
Look for an elongated brown true bug with widened leaf-like expansions on the hind tibiae.
Leaf-footed bug = leaves on the back legs.
Look for a small yellow-brown fruit fly with bold patterned wings and contrasting body markings.
Medfly = small patterned fruit fly.
Look for a microscopic threadlike roundworm or for feeder-root damage associated with citrus slow decline.
Nematode = microscopic thread worm on roots.
Look for the giant swallowtail caterpillar that mimics bird droppings with mottled brown, white and orange markings.
Orange dog = bird-dropping caterpillar.
Look for a tiny narrow-waisted wasp associated with parasitized scales/aphids/whiteflies; many are only a few millimeters long.
Parasitic wasp = tiny waist, big beneficial job.
Look for a curved elongated mussel-shell scale cover that is dark purple-brown.
Purple scale = curved dark mussel shell.
Look for reddish-brown ants of mixed worker sizes and characteristic mound colonies.
Fire ant = red-brown ants + mound.
Look for a wedge-shaped leafhopper with strong jumping hind legs and wings held roof-like over the body.
Sharpshooter = big wedge-shaped leafhopper.
Look on leaf undersides for tiny pale mites marked by multiple dark body spots; feeding can cause stippling.
Six-spotted = tiny pale mite, several dark dots.
Look for a broad bright-green shield-shaped true bug.
Green stink bug = green shield.
Look for tiny brownish-purple mites on upper leaf surfaces with stippled/gray foliage injury.
Texas mite = dark mite + stippled upper leaf.
Look for tiny white moth-like adults and pale oval scale-like nymphs on leaf undersides.
Citrus whitefly = little white moths under leaves.
Look for a small gray-brown snout weevil and repeated notches chewed from leaf margins.
Little leaf notcher = small gray weevil + edge notches.
Look for tiny slender yellow/tan insects and silvery or ring-like scarring on tender flowers/young fruit.
Thrips = tiny slivers + surface scarring.
Look for tiny pale yellow-green mites with two dark dorsal spots, often with fine webbing.
Two-spotted = two dark dots + webbing.
Look for the distinctive seedhead with two (sometimes three) racemes forming a V or Y shape.
Bahiagrass = V-shaped seedhead.
Look for a tendril-climbing vine with deeply lobed leaves and warty orange fruit that splits open to show bright red seed coverings.
Balsam apple = lobed vine + warty orange fruit.
Look for a fine-textured creeping grass with stolons/rhizomes and several finger-like seed spikes radiating from one point.
Bermuda = creeping mat + finger seedhead.
Look for alternate oval leaves, small white star-shaped flowers and clusters of shiny black berries when mature.
Nightshade = white stars + black berries.
Look for opposite toothed leaves and small daisy heads with yellow centers; mature seeds are narrow black needles with barbed tips.
Spanish needles = little daisy + barbed black seeds.
Look for deeply divided fern-like leaves and upright green flower spikes with no showy petals.
Ragweed = ferny leaf + green spike.
Look for a twining vine with extremely finely divided feathery leaves and small red star/trumpet flowers.
Cypress vine = morning glory with fern leaves.
Look for tall upright growth covered in very fine threadlike, feathery foliage.
Dogfennel = tall feathery plume.
Look for an upright branching weed with small narrow serrated leaves and tiny pale flowers.
Goatweed = small serrated leaves + tiny pale flowers.
Look for a tall coarse bunchgrass with broad blades and a large open branched seed panicle.
Guineagrass = giant bunchgrass + open panicle.
Look for irregularly lobed aromatic leaves and clusters of tiny green flowers on an upright branching plant.
Jerusalem oak = lobed aromatic weed.
Look for a tall rhizomatous grass with broad leaves, a conspicuous pale/white midrib and a large open often purplish panicle.
Johnsongrass = white midrib + big open panicle.
Look for triangular/goosefoot-shaped leaves with irregular teeth and a whitish mealy coating on young leaves.
Lambsquarter = goosefoot leaf + floury coating.
Look for opposite rough serrated leaves, square-ish stems and tight clusters of small multi-colored tubular flowers.
Lantana = rough leaf + multicolor flower cluster.
Look for a twining vine with opposite heart-shaped leaves and milky sap when damaged.
Milkweed vine = heart leaf + milk sap.
Look for a twining vine with heart- or arrow-shaped leaves and large funnel/trumpet flowers.
Morning glory = twining heart leaf + trumpet.
Roll the stem: sedges have solid triangular stems with glossy leaves arranged in three ranks and an umbrella-like seedhead.
Nutsedge = sedges have edges.
Look for a woody vine with compound leaves made of toothed leaflets and clusters of berries that mature blue-black.
Peppervine = toothed compound leaf + berry clusters.
Look for an upright Amaranthus with alternate simple leaves and dense green flower/seed spikes.
Pigweed = upright amaranth + dense green spike.
Look for a large coarse plant with thick reddish-purple stems and long drooping clusters of purple-black berries.
Pokeberry = red stem + hanging purple berry strings.
Look for a low spreading mat with opposite rough/hairy leaves and tiny white star-like flowers.
Pusley = low hairy mat + tiny white stars.
Look for a grass bearing hard spiny burs that readily stick to clothing, fur or skin.
Sandbur = grass with sticker burs.
Look for a broad-leaved creeping/decumbent grass with several seedhead branches carrying rows of spikelets along one side.
Signalgrass = broad grass + rowed racemes.
Look for an upright tough-stemmed weed with narrow toothed leaves and small yellow hibiscus-like flowers.
Teaweed = tough sida stem + tiny yellow mallow flower.
Look for a stiff creeping perennial grass spreading by pointed rhizomes, with narrow leaves and a sparse open panicle.
Torpedograss = tough rhizomes + sparse panicle.
Look for a woody climbing vine with five leaflets radiating from one point and tendrils for climbing.
Virginia creeper = five-finger vine.
Look for a basal rosette that bolts into branched stems bearing many tiny white flowers and flat round/oval seedpods.
Pepperweed = tiny white flowers + little flat pods.