Pascal Pittorino / Lemon tree (Citrus limon) covered in snow, Var, Provence, France, February.

Nigel Cattlin / Glasshouse mealy bug (Pseudococcus viburni) honeydew from infestation on Lemon (Citrus limon) fruit, cultivated in conservatory.

Nigel Cattlin / Glasshouse mealy bug (Pseudococcus viburni) infestation on Lemon (Citrus limon) fruit, cultivated in conservatory.

Nigel Cattlin / Californian red scale insect (Aonidiella aurantii) scales on Orange (Citrus sinensis) leaf, zonal chlorosis present. Native to China. Sicily, Italy. October.

Nigel Cattlin / Californian red scale (Aonidiella aurantii) infestation on Lemon (Citrus limon) wood. Native to China. Sicily, Italy. October.

Nigel Cattlin / Californian red scale (Aonidiella aurantii) infestation on Lemon (Citrus limon) wood. Native to China. Sicily, Italy. October.

Nigel Cattlin / Californian red scale (Aonidiella aurantii) infestation on Lemon (Citrus limon) stem. Native to China. Sicily, Italy. October.

Heather Angel / Sichuan pepper (Zanthoxylum bungeanum) branch with fruit.Sichuan, China. July.

Heather Angel / Common rue (Ruta graveolens) flower. Cultivated in herb garden, Surrey, England, UK. Native to Balkan Peninsula.

Heather Angel / Seville orange (Citrus aurantium) flower. Cultivated in glasshouse, Surrey, England, UK. Focus stacked. Sequence 1/2.

Heather Angel / Seville orange (Citrus aurantium) flower fluorescing in UV light, colour attractive to pollinators. Cultivated in glasshouse, Surrey, England, UK. Focus stacked. Sequence 2/2.

Edwin Giesbers / Lemon (Citrus limon), fruit growing on tree. Cyprus. April.

Matthew Maran / Green lime on white background, North London, England

Philippe Clement / Japanese bitter-orange (Poncirus trifoliata / Citrus trifoliata) citrus fruit in tree, October

Jiri Lochman / Plant biodiversity on stabilized coastal dunes with Shark Bay Rose (Diplolaena grandiflora) and Sandhill Wattle (Acacia ligulata) in the foreground, Shark Bay UNESCO Natural World Heritage Site, Weste...

Jiri Lochman / Shark bay rose (Diplolaena grandiflora) , Shark Bay UNESCO Natural World Heritage Site, Western Australia.

Jiri Lochman / Shark Bay rose (Diplolaena grandiflora), Shark Bay UNESCO Natural World Heritage Site, Western Australia.

Jiri Lochman / Shark bay rose (Diplolaena grandiflora), Shark Bay UNESCO Natural World Heritage Site, Western Australia.

Jiri Lochman / Shark bay rose (Diplolaena grandiflora), Shark Bay UNESCO Natural World Heritage Site, Western Australia.

Hanne & Jens Eriksen / Rue (Haplophyllum tuberculatum) close-up of flowers, Oman, March

Nick Upton / Oranges (Citrus sinensis) fruits ripening, Argolis, Peloponnese, Greece, August 2013.

Nick Upton / Unripe and ripe Oranges (Citrus sinensis) hanging on a tree in an orange grove, Argolis, Peloponnese, Greece, August 2013.

Pascal Pittorino / Lemon tree (Citrus limon) covered in snow, Var, Provence, France, February.

Juan Manuel Borrero / Orange (Citrus sinensis) tree flowers. Cultivated plant.

Martin Gabriel / Caucasian burning bush (Dictamnus caucasicus) flowering, Northern Armenia, May.

Martin Gabriel / Caucasian burning bush (Dictamnus caucasicus) flowering, Northern Armenia, May.

Vladimir Medvedev / Amur cork tree (Phellodendron amurense) branches with berries, Amur Region, Russia.

Vladimir Medvedev / Amur cork tree (Phellodendron amurense) trunk, Amur Region, Russia.

Cheryl-Samantha Owen / Oranges (Citrus sp) in orchard on Suikerbossie farm, Koue Bokkeveld / Cedarberg region, Western Cape, South Africa.

Cheryl-Samantha Owen / Oranges (Citrus sp) in orchard on Suikerbossie farm, Koue Bokkeveld / Cedarberg region, Western Cape, South Africa.

Cheryl-Samantha Owen / Orange (Citrus sp) orchard irrigation on Suikerbossie farm, Koue Bokkeveld / Cedarberg region, Western Cape, South Africa. The water comes from rainwater, mountain run-off and the Twee River, which fl...

Cheryl-Samantha Owen / Orange (Citrus sp) orchard irrigation on Suikerbossie farm, Koue Bokkeveld / Cedarberg region, Western Cape, South Africa. The water comes from rainwater, mountain run-off and the Twee River, which fl...

Cheryl-Samantha Owen / Farm workers harvesting Oranges (Citrus sp) on Suikerbossie farm, Koue Bokkeveld / Cedarberg region, South Africa. February 2014.

Cheryl-Samantha Owen / Trailers of harvested Oranges (Citrus sp) on Suikerbossie farm, Koue Bokkeveld / Cedarberg region, South Africa. February 2014.

Chris Mattison / Butterwort (Pinguicula gigantea) leaves, insectivorous plants, cultivated specimen.

David Noton / Fruits and vegetables for sale in market in Luang Prabang, Laos, March 2009.

David Noton / Fruits and vegetables for sale in market in Luang Prabang, Laos, March 2009.

Adrian Davies / Mould (Penicillin italicum) growing on a Satsuma (Citrus unshi)

Adrian Davies / Mould (Penicillin italicum) growing on a Satsuma (Citrus unshiu)

Hanne & Jens Eriksen / Mandarin fruit {Citrus nobilis} growing on tree, Florida, USA

Niall Benvie / Orange {Citrus sp.} with mould growing on it, UK

Nature Production / Satsuma Mandarin flower {Citrus unshiu} Japan

WILLIAM OSBORN / Citrus blossom, Cumquat orange, {Citrus sp} Queensland, Australia

Adrian Davies / Mould on Satsuma under visible light (top) and fluorescing under UV light (bottom).

Etienne Littlefair / Checkered swallowtail butterfly (Papilio demoleus) resting on a plant stem, Adelaide River Hills, Northern Territory, Australia.

Loic Poidevin / Diosma (Diosma hirsuta) in flower, Cotes d'Armor, Brittany, France. April.

Adrian Davies / Satsuma (Citrus sp.) with mould (Penicillium sp.), in visible light at top and fluorescing in UV light below.

Adrian Davies / Cross section of fruit in visible light, and fluorescing in UV light on black background. Top: Orange; Centre: Kiwi; Bottom: Pomegranate.

Adrian Davies / Bowl of fruit in UV light showing mould on Satsuma (Citrus sp.). See 1729463.

Adrian Davies / Bowl of fruit in visible light showing mould on Satsuma (Citrus sp.). See 1729464.

Paul Harcourt Davies / Ruby-tailed / Cuckoo wasp (Chrysis comparata) feeding on Rue flower (Ruta graveolens). Podere Montecucco, Orvieto, Italy. June.

Dave Watts / Mexican orange blossom (Choisya ternata) with dead branches and leaves caused by extreme heat and over 3 months of drought, Natural Park of Haut Languedoc, Herault , Southern France. August, 2022.

Dave Watts / Mexican orange blossom (Choisya ternata) with dead branches and leaves caused by extreme heat and over 3 months of drought, Natural Park of Haut Languedoc, Herault , Southern France. August, 2022.

Philippe Clement / Chinese prickly-ash (Zanthoxylum simulans) close-up of spines on tree trunk. Native to China and Taiwan.

Paul Harcourt Davies / Dittany (Dictamnus albus) in flower in woodland, Orvieto, Umbria, Italy. May.

Nigel Cattlin / Normal, mono-embryonic Orange (Citrus sinensis) seedlings with normal single development of root and shoot.

Nigel Cattlin / Two polyembryonic Orange (Citrus sinensis) seedlings showing bifurcation, a malformation, with each seed developing two plants.

Paul Harcourt Davies / Caterpillar of Common yellow swallowtail butterfly (Papilio machaon), dark morph, feeding on Common rue (Ruta graveolens) as a foodplant, Umbria, Italy. October.

Paul Harcourt Davies / Caterpillar of Common yellow swallowtail butterfly (Papilio machaon), dark morph, on Common rue (Ruta graveolens) as a foodplant, Umbria, Italy. October.

Paul Harcourt Davies / Caterpillar of Common yellow swallowtail butterfly (Papilio machaon) on Common rue (Ruta graveolens) as a foodplant, Umbria, Italy. October.

Paul Harcourt Davies / Buff-tailed bumblebee (Bombus terrestris) visiting flower of Dittany (Dictamnus albus), Umbria, Italy. May.

Paul Harcourt Davies / Citrus mealybugs (Planococcus sp.) resting on leaf, Umbria, Italy. May.

Paul Harcourt Davies / Dittany (Dictamnus albus) in flower, in woodland, Umbria Italy. May.

Paul Harcourt Davies / Lemon (Citrus limon) flower, Umbria, Italy. June.

Paul Harcourt Davies / Lemon (Citrus limon) flower, buds and fruit, Umbria, Italy. June.

Bruce Thomson / Orange-backed troupial (Icterus croconotus) feeding in orange tree, Pocone, Brazil.

Nigel Cattlin / Olleocellosis / Green spot, a physiological rind disorder causing blemishes in orange peel after rupture of the peel oil glands causing a toxic reaction in the pericarp cells.

Nigel Cattlin / Stem end rot (Lasiodiplodia theobromae) on stored lemon (Citrus limon) fruit crop.

Nigel Cattlin / False codling moth (Thaumatotibia leucotreta) caterpillar on Orange (Citrus sinensis) fruit, South Africa.

Nigel Cattlin / Severe marginal chlorosis to the leaves of a mature Lemon (Citrus limon) tree caused by calcium deficiency, South Africa.

Nigel Cattlin / Citrus bud mite (Aceria sheldoni) damage 'Hand of Buddha' distortion to a Lemon (Citrus limon) fruit, South Africa.

Nigel Cattlin / Citrus leaf miner (Phyllocnistis citrella) leaf mines made by larvae in a Pummelo (Citrus maxima) leaf, Thailand, South East Asia.

Barry Mansell / Little leaf notcher (Artipus floridanus) pair mating on leaf, pest of lawns and citrus plants, North Florida, USA.

Barry Mansell / Little leaf notcher (Artipus floridanus) pair mating on leaf, pest of lawns and citrus plants, North Florida, USA.

Barry Mansell / Citrus root weevil (Draprepes abbreviatus) on leaf, North Florida, USA. Controlled specimen.

Nigel Cattlin / Citrus mealybug (Planococcus citri) infestation on the leaves and stem of a bougainvillea (Nyctaginaceae) grown on a conservatory, Berkshire, UK, April.

Eladio Fernandez / A lime butterfly (Papilio demoleus) rests on a leaf after a light rain in the Jardin Botanico de Santo Domingo. This butterfly species is a recent introduction to island of Hispaniola (Dominican Repub...

Eladio Fernandez / A lime butterfly (Papilio demoleus) rests on a leaf after a light rain the Jardin Botanico de Santo Domingo, Dominican Republic. This species was introduced and feeds primarily on citrus. Sometimes it...

Nigel Cattlin / Rows of orange trees (Citrus sinensis) with green, maturing fruit in an orchard in the Low Veldt, Transvaal, South Africa, February

Nigel Cattlin / Rows of orange trees (Citrus sinensis) with green, maturing fruit in an orchard in the Low Veldt, Transvaal, South Africa, February

Nigel Cattlin / Lance spraying of orange (Citrus sinensis) trees in fruit with pesticide without safety protection, South Africa, February

Derek Galon / Ripe grapefruits on a tree (Citrus paradisi). Dominica, Eastern Caribbean.

Franco Banfi / Lemons for sale at market, Penisola Sorrentina, Costa Amalfitana, Italy,

Franco Banfi / Stall with chilli peppers, garlic, limoncello, lemons and citrons, Penisola Sorrentina, Costa Amalfitana, Italy.

Dave Watts / Whitey wood (Acradenia frankliniae). Tasmania, Australia. November.

Dave Watts / Stinkwood (Zieria arborescens). Tasmania, Australia. October.

Dave Watts / Tasmanian waxflower (Philotheca virgata). Tasmania, Australia. November.

Dave Watts / Satin wood (Nematolepis squamea). Tasmania, Australia. October.

Dave Watts / Common correa (Correa reflexa). Tasmania, Australia. November.

Dave Watts / Common correa (Correa reflexa). Tasmania, Australia. January.

Dave Watts / White correa (Correa alba). Tasmania, Australia. January.

Dave Watts / Hairy boronia (Boronia pilosa). Tasmania, Australia. November.

Dave Watts / River boronia (Boronia gunnii). Tasmania, Australia. November.

Dave Watts / Lemon-scented boronia (Boronia citriodora). Tasmania, Australia. January.

Dave Watts / Stinky boronia (Boronia anemonifolia). Tasmania, Australia. November.