Carrot

Taxonomy of the carrot (Daucus carota L.) according to Cronquist System
Dominium/SuperKingdom: Eukariota
Regnum/Kingdom: Plantae (Plants/Piante)
Subregnum/Subkingdom: Tracheobionta (Vascular plants)
Superdivisio/Superdivision: Spermatophyta (Seed plants)
Divisio/Division: Magnoliophyta Cronquist, 1996 (Flowering plants/Piante con fiori)
Subdivisio/Subdivision: Magnoliophytina Frohne & U. Jensen ex Reveal, 1996
Classis/Class: Rosopsida Batsch, 1778 (Dicotyledons/Dicotiledoni)
Subclassis/Subclass: Cornidae Frohne & U. Jensen ex Reveal, 1994
Superordo/Superorder: Aralianae Takht., 1967
Ordo/Order: Araliales Reveal, 1996
Familia/Family: Apiaceae Lindl., 1836
Subfamilia/Subfamily: Daucoideae Burnett, 1835
Tribus/Tribe: Dauceae W.D.J. Koch, 1824
Subtribus/Subtribe: Daucinae Dumort., 1827
Genus: Daucus Linnaeus, 1753
Species: Daucus carota Linnaeus, 1753
Taxonomy of the carrot (Daucus carota L.) according to APG System
Kingdom: Plantae (Plants/Piante)
Clade: Angiosperm
Clade: Eudicots
Angiosperme tricolpate
Core Tricolpate
Asterids
Euasterids II
Ordo/Order: Araliales
Familia/Familya: Apiaceae Lindl., 1836
Subfamilia/Subfamily: Daucoideae Burnett, 1835
Tribe: Dauceae W.D.J. Koch, 1824
Subtribus/Subtribe: Daucinae Dumort., 1827
Genus: Daucus Linnaeus, 1753
Species: Daucus carota Linnaeus, 1753



Generalità e dati statistici
La carota è una pianta erbacea appartenente alla famiglia delle Umbelliferae. Il suo nome scientifico, oltre che Daucus carota, ha dei sinonimi: Daucus gingidium L. subsp. gingidium, Daucus gingidium L., Daucus communis Rouy & E.G. Camus; Daucus carota L. var. sativa DC., Daucus carota L. subsp. sativus (Hoffm.) Arcang. var. sativus Hoffm., Daucus sativus (Hoffm.) Röhl.
  • ARABIC: نبات الجزر‏
  • BENGALI: Gaajara.
  • CHINESE: Hu luo bo, Hu luo bo, Hong luo bo, Huang luo bo, Hu lu fai, Hong lu fai , Hong da gen, Yang hua luo bo, Hong cai tou.
  • DANISH: Gulerod, Have-gulerod, Spisegulerod, Karotter, Gullerødder.
  • DUTCH: Wortel, Peen.
  • ENGLISH: Carrot, Carrots.
  • FINNISH: Porkkana, Ruokaporkkana, Viljelty porkkana.
  • FRENCH: Carotte, Carottes.
  • GERMAN: Gelbe Rübe, Karotte, Karotten, Möhre, Mohrrübe, Speisemöhre, Speisemöhren.
  • GREEK: Kαρότο Karoto.
  • HEBREW: גזר‬.
  • HINDI: Gajar.
  • ITALIAN: Carota, Carote.
  • JAPANESE: ニンジン Ninjin.
  • KHMER: Karôt.
  • KOREAN: Dang geun.
  • MALAY: Lobak merah, Boktel.
  • NEPALESE: Gaajar.
  • NORWEGIAN: Gulrot.
  • PORTUGUESE: Cenoura, Cenouras.
  • RUSSIAN: Морковь Morkov, Морковь дикая Morkov' dikaia, Морковь обыкновенная Morkov' obyknovennaia.
  • SUNDANESE: Bortol.
  • SPANISH: Zanahoria, Zanahorias.
  • SWEDISH: Morot.
  • TAGALOG: Karot.
  • TAMIL: Karuvathu kelengu.
  • THAI: Khaerot. The carrot is a root vegetable, usually orange in colour, though purple, red, white, and yellow varieties exist. It has a crisp texture when fresh. The most commonly eaten part of a carrot is a taproot, although the greens are edible as well. It is a domesticated form of the wild carrot Daucus carota, native to Europe and south-western Asia.
    The domestic carrot has been selectively bred for its greatly enlarged and more palatable, less woody-textured edible taproot.
    It is a biennial plant which grows a rosette of leaves in the spring and summer, while building up the stout taproot, which stores large amounts of sugars for the plant to flower in the second year. The flowering stem grows to about 1 m tall, with an umbel of white flowers that produce a fruit called a mericarp by botanists, which is a type of schizocarp.
    The wild ancestors of the carrot are likely to have come from Iran and Afghanistan, which remains the centre of diversity of Daucus carota, the wild carrot. Selective breeding over the centuries of a naturally occurring subspecies of the wild carrot, Daucus carota subsp. sativus, to reduce bitterness, increase sweetness and minimize the woody core, has produced the familiar garden vegetable.
    In early use, carrots were grown for their aromatic leaves and seeds, not their roots. Some relatives of the carrot are still grown for these, such as parsley, fennel, dill and cumin. The first mention of the root in classical sources is in the 1st century CE.
    The modern carrot appears to have been introduced to Europe in the 8-10th centuries.
    The 12th century Arab Andalusian agriculturist, Ibn al-Awwam, describes both red and yellow carrots; Simeon Seth also mentions both colours in the 11th century. Orange-coloured carrots appeared in the Netherlands in the 17th century.
    Cultivars
    Carrot cultivars can be grouped into two broad classes, eastern carrots and western carrots. More recently, a number of novelty cultivars have been bred for particular characteristics.
    The city of Holtville, California, promotes itself as "Carrot Capital of the World", and holds an annual festival devoted entirely to the carrot.
    Eastern carrots
    Eastern carrots were domesticated in Central Asia, probably in modern-day Iran and Afghanistan in the 10th century, or possibly earlier. Specimens of the eastern carrot that survive to the present day are commonly purple or yellow, and often have branched roots. The purple colour common in these carrots comes from anthocyanin pigments.
    Western carrots
    The western carrot emerged in the Netherlands in the 17th century, from Iran with violet colour, its orange colour making it popular in those countries as an emblem of the House of Orange and the struggle for Dutch independence. The orange colour results from abundant carotenes in these cultivars. While orange carrots are the norm in the West, other colours do exist, including white, yellow, red, and purple. These other colours of carrot are raised primarily as novelty crops.
    The Vegetable Improvement Center at Texas A&M University has developed a purple-skinned, orange-fleshed carrot, the BetaSweet (also known as the Maroon Carrot), with substances to prevent cancer, which has recently entered very limited commercial distribution, through J&D Produce of Edinburg, Texas. This variety of carrot is also known to be high in β-carotene which is an essential nutrient. The high concentrations of this nutrient give the carrot its maroon shade.
    Western carrot cultivars are commonly classified by their root shape:
    • Chantenay carrots are shorter than other cultivars, but have greater girth, sometimes growing up to 8 cm (3 in) in diameter. They have broad shoulders and taper towards a blunt, rounded tip. They are most commonly diced for use in canned or prepared foods.
    • Danvers carrots have a conical shape, having well-defined shoulders and tapering to a point at the tip. They are somewhat shorter than Imperator cultivars, but more tolerant of heavy soil. Danvers cultivars are often puréed as baby food. They were developed in 1871 in Danvers, Madison.
    • Imperator carrots are the carrots most commonly sold whole in U.S. supermarkets; their roots are longer than other cultivars of carrot, and taper to a point at the tip.
    • Nantes carrots are nearly cylindrical in shape, and are blunt and rounded at both the top and tip. Nantes cultivars are often sweeter than other carrots.
    While any carrot can be harvested before reaching its full size as a more tender "baby" carrot, some fast-maturing cultivars have been bred to produce smaller roots. The most extreme examples produce round roots about 2.5 cm (1 in) in diameter. These small cultivars are also more tolerant of heavy or stony soil than long-rooted cultivars such as “Nantes” or “Imperator”. The "baby carrots" sold ready-to-eat in supermarkets are, however, often not from a smaller cultivar of carrot, but are simply full-sized carrots that have been sliced and peeled to make carrot sticks of a uniform shape and size.
    The choice of the varieties can be carried out in relation to the destination of the product trades them, that is for fresh market or for industry:
    • varieties for fresh market:
      • Napoli;
      • Bolero;
      • Premia;
      • Puma;
      • Nandor.
    • varieties for processing industry:
      • Kamaran;
      • Karotan;
      • Krakov;
      • Macon;
      • Maxima;
      • Napoli.

    They are indicated some varieties and hybrids of carrot cultivated in Italy submitted to some tests of varietal comparison:
    • F1 hybrid “Turbo” (figure 1): it is a new hybrid, early, Nantes type, obtained in France after long and patients studies. The roots are much homogenous, long cm 18-20, harmoniously formed without green collar; they are of optimal presentation and good coloration in the external and internal part. “Turbo” is apt variety to the mechanical harvesting and for its foliage of dark-green colour, not wide, it is suitable for the harvesting “to little bunch”. It is also apt for any type of soil to the north and the south of Italy, provided that loose, permeable and of good fertility.
    • F1 hybrid “Nandor” (figure 2): Carrot of the type Nantes, middle long (18-20 cm.), perfectly cylindrical, smooth down, of colour red alive; absolutely without heart and green collar. This exceptional variety is indicated for spring-summery sowing and summer and autumn harvesting.
    • “Amsterdam 2 selection Sweetheart” (figure 3): it is a middle long carrot that prefers loose soils where it can be seeded from February to August. This carrot is perfumed, sweet, crystalline root, practically without heart, ideal also for the “mignon” carrot production.
    • “Belicum 2 selection Oranza” (figure 4): it is a carrot with a long and cylindrical root, with obtuse tip root, without ring. Pulp of intense colour, sweet, aromatic, crystalline. Vigorous foliage. Of optimal storage, with scalar harvest from June to November, catching up easy unitary yields of 50 t/ha.
    • “Flakkee 2” (figure 5): it is a carrot bulky and long. It is obtuse, with tip finishes lengthened them. Resistant foliage also to the summery heats.
    • “Mezza lunga nantese 2” (figure 6): early, without heart, cylindrical, of medium size.
    • “Rubrovitamina lunga” (figure 7): long root, of large sizes, to log-conical form and of intense red colour, rich in carotene and vitamin B. early relatively variety and of elevated production, is indicated or from fresh market, for the transformation or druggist industry.
    • “Lunga rossa ottusa” (figure 8): Variety with very long root, it supplies great yield; the preferred one on the markets and for the homely consumption. Heart of reduced proportions
    • “Chantenay” (figure 9): it is a carrot middle long, cultivated for the optimal yields in roots that are of conic form.


    Figure 1 - F1 hybrid “Turbo”.

    Figure 2 - F1 hybrid “Nandor”.

    Figure 3 - “Amsterdam 2 selezione Sweetheart”.

    Figure 4 - “Belicum 2 selection Oranza”.

    Figure 5 - “Flakkee 2”.

    Figure 6 - “Mezza lunga nantese 2”.

    Figure 7 - “Rubrovitamina” a long carrot.

    Figure 8 - “Lunga rossa ottusa”.

    Figure 9 - Variety “Chantenay”.



    Carrot flowers are pollinated primarily by bees. Seed growers use honeybees or mason bees for their pollination needs.
    Carrots are used as food plants by the larvae of some Lepidoptera species, including Common Swift, Garden Dart, Ghost Moth, Large Yellow Underwing and Setaceous Hebrew Character.
    One particular variety lacks the usual orange pigment from carotenes, owing its white colour to a recessive gene for tocopherol (Vitamin E).
    Carrots are so called biennial plants and only flower every two years. In the first year the plant produces the edible root and a leafy top. If a carrot plant is left in the ground for another year, it flowers and seeds are produced.
    Sexual reproduction in carrots is therefore not different from other flowering plants. Pollen is produced and transferred to the female part of the flower, the stigma. The pollen grain then delivers the sperm cells within it to the ovary via a long tube where fertilisation takes place.
    The birds-nest-shaped fruit cluster of carrot has a remarkable mechanism for seed dispersal. The stalks are hygroscopic, so that when conditions are dry and suitable for seed dispersal they bend outward, exposing the fruits to wind and animals; when conditions are wet, they bend inwards, forming the familiar bird’s nest structure, which protects the seeds.
    The Carrot is not a fruit, so there are no seeds inside or on the carrot. The part of the carrot that you eat grows in the ground, usually with the wide end of the carrot just at the surface of the soil. The round mark you can see on that end of the carrot is where the leaves used to be - a big soft bunch of deep green leaves that look a bit like a fern.
    When the carrot is ready, it sends up a tall stem, which produces flowers, and eventually seeds. The seeds are very small and black, and look like full stops (periods) on a page. There are approximately 1,000 in a gram, roughly 3000 would fill a teaspoon.
    If you are planning to grow carrots, letting one go to seed may not be the best solution. Carrots are biennial - that means they take two years to reach maturity when they can produce seeds. Secondly, the vast majority of carrots that you buy from the supermarket are F1 hybrids. That means the seed comes from TWO parents who are different. (One may be big and fat, while the other is fast growing and a nice colour.)
    By using pollen from one to fertilise the flowers of the other (the grower aims to produce carrots which are big and fat and fast and a good colour). The resultant carrot may be just what the farmer wants, but there are usually two problems for the consumer. The carrot may not have taste (low on the farmers list of priorities, because you can't cook and taste before you buy and in the vast majority of cases, F1 hybrids are sterile.
    If you grow an F1 carrot and harvest the seed (after two years) they may very well not grow. In some cases you just get no flowers or seeds at all.
    Carrots are biennial, flowering in their second year of growth (figure 10). In areas with mild winters, leave your carrots in the ground, mulching them heavily. The foliage will die back in autumn, but will then re-sprout and start to flower in the spring. In colder areas, dig up your carrots in the autumn, and select the best coloured and shaped roots. Twist off the foliage, and store the roots in a box of dry sand in a frost free place, making sure that they don't touch. In spring, replant the roots, and they will re-sprout and flower (figure 11).
    If you want to maintain a carrot variety effectively, you really need to save seed from at least 40 good roots to maintain good genetic diversity. If you have too small a genetic pool, you will end up with small, poor quality roots in a very few generations.
    Carrots grow into big plants waist high or taller, producing successive branches with large flat umbels of flowers (figure 12). They are insect pollinated, and need to be isolated from other flowering carrot varieties by at least 500 m in an open field situation. This is not normally a big problem, since few people let their carrots go to seed. However, they will cross with wild carrot (“Queen Anne's Lace”), giving thin white useless roots. As with all insect pollinated crops, barriers such as houses, tall hedges and other high crops can affect insect flight paths drastically, so you don't necessarily need to eliminate all “Queen Anne's Lace” within a 1-2 km radius; but do watch out for any white roots in subsequent generations and get rid of them.
    To harvest your carrot seed, keep an eye on the umbels of flowers, and cut them off with secateurs as they start to turn brown and dry (figure 13). If you have plenty of plants, just save seed from the first and second umbels of flowers to appear on each plant, as these will give the biggest and best seed. Dry the seed heads further inside, and then rub them between your hands or in a sieve to separate them. You will notice that the seeds have a “beard” which is removed in commercial seed to make them easier to pack.
    You can sieve the seeds further to remove more of the chaff, but there is no need to get the seed completely clean - just sow slightly more thickly to allow for the chaff mixed in.
    Dried carrot seed (figure 14) is relatively short lived, but if it is stored somewhere cool and dry, it should give good germination for 3 years. Seeds can be safely stored for at least three years. Place seeds in jars, manila envelopes, cloth or mesh bags, plastic containers, or foil envelopes. The best containers are air-tight, such as a sealed glass jar, metal can, or foil envelope. Protect seed from sunlight.Store seeds in a cool (below 15 °C is ideal), dry location. Place the seeds in a refrigerator for long term storage.
    For short-term storage, keep the seeds in a cool, shady and dry place.


    Figure 10 – Carrot plants old two years.

    Figure 11 – Joung inflorescence of carrot.

    Figure 12 – Infructescence of carrot.

    Figure 13 – Mature infructescence of carrot.

    Figure 14 - Carrot Seed under the microscope.



    What do seeds contain and how do they work?
    A seed is the product of a fertilised ovule . It is the means by which the progeny of a plant can be spread. The seed contains the embryo from which a new plant will grow. The seed contains a supply of food called the endosperm that is used by the new plant to develop. The whole seed is covered in a seed coat known as the testa. Seeds are found in a great variety of types.
    The testa protects the contents of the seed. For the seed to grow the testa needs to split. The seed imbibes water which causes it to swell and split open the testa. The seed coat varies between different types of seed, which in turn affects, the uptake of water. Some seed coats are very thick and need to go through a process of scarification to allow absorption of water. In the wild this would occur by the gnawing actions of animals, passing through an animal's digestive tract or abrasion by a rocky surface. In the artificial environment of gardening this process is imitated by nicking the seed coat with a sharp knife or rubbing with sandpaper.
    If a seed has a thin coat the presence of light can either encourage or inhibit seed growth. Smaller seeds tend to require light for germination.

    Carrots can taste soapy or bitter
    Two ingredients determine a carrot's flavour: sugars and terpenoids (volatile compounds that impart the carrot flavour). Some varieties are naturally high in terpenoids, which make the carrots taste bitter or soapy. Because terpenoids develop earlier than sugars, a carrot that is harvested too young might taste bitter.
    The taste in carrots is based on the right balance of sugars and terpenoids. Terpenoids produce a soapy turpentine-like taste that will mask sweetness. Differences in flavour components have been found to be attributable more to genetics than to climatic conditions; however, the controversy continues. Volatiles can also increase during cold storage (around -1 °C) which is a common practice (even for organics).
    Many different terpenes in carrot can cause a turpentine-like taste. Usually terpenes give a desirable taste to carrots, but in high concentrations can give undesirable taste. Factors influencing undesirable taste include genetics, growing conditions, diseases and insects, post-harvest handling and storage atmosphere.
    Storing carrots near apples or other fruits that manufacture ethylene gas as they ripen, encourages the development of terpenoids in the vegetable and causing them to become bitter when exposed to ethylene.
    Raw carrots will taste more soapy than cooked ones, as cooking breaks down the terpenoids allowing the sweetness to come through.
    The Nantes variety produces roots which have higher sugar content, lower in terpenoids and less suitable for long-term storage.
    A lot depends on the growing conditions ( if you grow your own) - the flavour is best if they mature when days are warm and sunny and nights are cool and still. The plant is photosynthesizing like crazy in the daytime and putting a lot of sugars down into the root, then a cool night comes and the carrot 'rests' instead of burning up that sugar. Where the night time temps stay in the 60s or warmer, the plants respire more at night and use up the accumulated sugars. So for the sweetest roots, time your carrot crop to mature at a time of year with warm days and chilly nights. and no matter what the conditions, harvest late in the day rather than in the early morning.
    One old wives tale I have heard, but not proven - take 2 pounds of carrots and boil them with three whole cloves and a bit of salt, is supposed to make them sweeter. (if you try this do tell me what you observe).

    How to get a good crop
    Carrots prefer light sandy soils so if your garden earth is on the light side you will have no problem. If you garden on clay or stony land then your carrots will always struggle. You will not fail so long as you are careful which varieties you choose - round or stumpy rooted types will succeed practically anywhere, whereas long rooted, tapering types will faulter. Carrots do well in containers. Choose pots which are at least 12 inches deep and give them good drainage. Use potting compost and keep them moist at all times. For best results try small varieties such as Parmex, Oxheart of Little Finger.
    If soil or space is a big issue for you please note that Carrots and other root vegetables will grow well in containers as long as the pot is deep enough. Be sure to choose a container that is twice as deep as the length of the carrot at maturity.

    Maintenance
    The first few weeks after sowing determine the size of your crop. Carrots do not tolerate a deep planting in a dry bed, so the trick is to offer them a shallow sowing with even moisture. The seedlings grow slowly and can't compete with weeds. As they develop top dress with old manure or compost, avoid "hot" nitrogen sources like fresh manure and fish fertilizer as they cause new roots to "burn off" and fork.
    Hand weeding is recommended until the carrots are 5cm tall. Thin the carrots to 8cm apart, then mulch with clean straw and compost to keep the weeds at bay.
    Mulching also helps the soil retain moisture and prevents "green shoulder," which is caused by exposing the crowns of the carrots to the sun, making the roots bitter. If the tops of your carrot roots start to turn green, pull the soil up around them. Over watering your carrots can cause the roots to crack.

    Harvesting
    Most carrots can be harvested in less than three months. they can be picked anytime they reach a usable size. The largest carrots will have the darkest, greenest tops, but don't leave the roots in the ground too long or they will be tough. Most are at their prime when about 2.5 cm in diameter at the crown.
    Do not be fooled by the tops which can be quite bushy but in fact the carrots themselves are quite small. When harvesting, drench the bed with water first, making the carrots easier to pull. When you find a carrot large enough, grasp the greens at the crown and tug gently with a twisting motion. If the greens snap off, carefully lift the roots with a small fork. Use damaged roots right away and store unblemished ones.
    Lifted carrot should not be left on the ground surface for too long as they will attract the attention of carrot fly. Cut the leaves off as soon as they are out of the ground; as long as they are attached they continue to keep growing and draw moisture and nourishment from the roots. During the first five months of storage, carrots will actually increase their vitamin A content; and, if protected from heat or light, can hold their nutrient content for another two or three months. Since carrots are rich in beta carotene, steaming them makes this nutrient more readily availability to the body as heat breaks down the tough cellular walls that encase the nutrient. The crisp texture of carrots is the result of the cell walls being stiffened with the indigestible food fibers cellulose, hemicellulose, and lignin

    Diseases and disorders


    Figure 15 – Corky Crown Rot. Caused by Streptomyces species Corky crown rot does not deteriorate in storage. Usually associated with potatoes as previous crops.

    Figure 16 – Carrot Scab. Streptomyces species Scab lesions do not deteriorate storage. Usually associated with potatoes as previous crops.

    Figure 17 – Tiger Stripe or Ring Rot Disease. Caused by Phytophthora species This disease can develop in the field and sometimes become apparent only after storage or in transit. Usually associated with poor drainage and in ground storage.


    Figure 18 – Cavity Spot. Caused by Pythium sulcatum. The cavities can increase in size in storage. Incidence appears to increase with multiple carrot cropping.


    Figure 19 – Smooth Crown Rot. Caused by Fusarium species, Rhizoctonia, or Sclerotinia. Usually does not deteriorate in storage. Wet conditions favour this disease, which increases in severity over time.


    Figure 20 - Sclerotinia Rot. Caused by Sclerotinia sclerotiorum. Rot may spread in storage to the rest of the infected carrot, or to adjacent carrots. Wet and warm conditions favour this disease.


    Figure 21 - Sour Rot. Caused by Geotrichum species. This disease can develop in the field and in storage. Associated with poor drainage.


    Figure 22 - Sour Rot. Caused by Geotrichum species. This disease can develop in the field and in storage. Associated with poor drainage. On the left (in low) it is possible to see a small crack on the thin tip.


    Figure 23 - Black Ring Rot. Black ring rot develops when stem decay, due to bacterial or fungal rot, spreads into the crown tissues. Severe rot can develop if the crop is left in the field long after plant maturity.


    Figure 24 - Violet Root Rot. Caused by Rhizoctonia crocorum. Lesions will enlarge and merge as the disease progresses the field causing large areas of decay. Shallow lesions on carrots at harvest can enlarge and deteriorate in storage. Associated with poor drainage.

    Figure 25 - Carrot Black Scurf. Caused by Rhizoctonia solani Not normally considered a problem, as the sclerotes are removed during the washing process. The carrots do not deteriorate in storage . Usually associated with potatoes as previous crops. You can see black sclerotia of Rhizoctonia on carrot surface.


    Figure 26 - Carrot Forking. Up, Forking of carrots due to tip damage by Pythium.Down, Forking of carrots due to tip damage by root-knot nematodes. Factors that can damage root tips, such as Pythium, root-knot nematodes and soil compaction, can cause carrot forking.



    The following figures show carrots that are also rejected but for causes due to other non-disease factors: shadow, weather damage, crack, bolters, misshappen, insect damage, splits, broken, greening and scaly skin.

    Figure 27 – Shadow.

    Figure 28 – Weather damage.

    Figure 29 – Crack.

    Figure 30 – Bolters.


    Figure 31 – Misshappen.

    Figure 32 – Insect damage.

    Figure 33 – Splits.

    Figure 34 – Broken.

    Figure 35 – Greening (up) and scaly skin (down).



    Pests
    The carrot fly, Psila rosae Fabricius 1794 (figure 36) is a serious and widespread pest and is really the only pest worth worrying about. The damage is done by the grubs tunnelling into carrot roots, disfiguring them and allowing moulds to gain a hold.

    Figure 36 – Carrot fly, Psila rosae Fabricius 1794, is an insect belongin to Diptera Psilidae, causing serious damages to carrot.



    How do you know you have a Carrot Fly attack? Basically you will not know until you lift the crop. In severe infestations the first sign is that the Carrot leaves look an orange, reddish, rusty colour. They then turn yellow. On lifting an affected Carrot it will be seen that the root end will be black or dark. Close examination of what appear to be good Carrots may reveal small holes in the Carrot. If Carrots are put in a bucket of water badly affected ones will come to the surface. This however does not mean that those which do not float are totally unaffected.
    Covering the crop with Enviromesh or similar is the best method of fly control. The carrot fly locates its carrots by scent. Crushing the foliage may make them easier to find so leave them alone! If you must weed the carrots, do it on a dry evening with no wind, as the scent of the bruised foliage will not spread so far, and carrot flies take wing in bright sunlight. Pull carrots for eating in the evenings too, for the same reason.
    You will often see the suggestion that growing onions in between the carrots keeps the carrot fly at bay. The idea is that the onion smell fools the female fly, which is otherwise attracted by the lingering foliage scent after carrot thinning. Alas this lovely romantic idea rarely works in practice. Onions can only be effective when the onions are in active leaf growth. Best results come from four rows of onions for every one of carrots and the beneficial effects will diminish as the onions start to bulb.
    Other strongly scented plants such as French or African marigolds, pennyroyal and garlic have all been suggested in the past, but have insufficient data to back up their claims. Mix carrot seed in with a packet of mixed annuals and sow as usual. A mixed crop should sustain less damage than a monocrop.
    You can also emulate commercial organic growers method of timing your sowings to miss the egg laying season. This means sowing in February or early March, or waiting until Mid June.

    Carrot Fly are low fliers
    One simple method for a home grower is grow in pots and put them on a table. The fly whizz past at no more than 18 inches above ground level.
    Mulching with grass cuttings can make it harder for the female flies to find a suitable egg laying site. The crop appears to benefit from the extra support given by the earth and you'll have noticeably fewer carrots with green shoulders. The mulch enables the carrots to make better use of nutrients and water in the soil, encouraging healthy growing conditions and improving their ability to resist attack. It also makes it more difficult for the female flies to lay their eggs in cracks in the soil. A range of creatures will make their home under the mulch, some of which will be predators of the carrot fly such as ground beetles and centipedes. Watch out for slugs and snails who will also thrive in these conditions.
    Location can be vital. However unappealing to the gardener, a windswept site with little protection is ideal. Carrot fly adults are weak fliers and tends to lurk round field edges or garden margins.
    A couple of varieties offer some resistance to the problem these are "Fly Away" and "Sytan". If the problem is serious in your area these will probably be attacked with the rest. Best results are obtained if no other variety is grown alongside. Autumn King types are carrot fly's favourites, so avoid sowing these if there is a known problem.
    Some seed companies suggest a "sacrificial strip" in that you should grow Flyaway or Resistafly alongside non resistant varieties such as early Nantes. This will allow any carrot fly in the area to attack the non resistant row, otherwise a minor attack can still occur.

    You can also try to reduce this pest by placing a sprig of wormwood around the plants crown. This masks the scent of carrots and the flies should leave them alone. Other plants to try include black salsify (oyster plant), coriander, lettuce, onion family, pennyroyal, rosemary and sage.

    Detecting of Carrot Fly
    Basically you will not know until you lift the crop. In severe infestations the first sign is that the Carrot leaves look an orange / reddish / rusty colour. They then turn yellow. On lifting an affected Carrot it will be seen that the root end will be dark or black. Close examination of what appear to be good Carrots may reveal small holes in the Carrot. If Carrots are put in a bucket of water, badly affected ones will come to the surface. This however, does not mean, that those which do not float are totally unaffected. More Detail on Carrot Fly:
    • An adult carrot (or "rust") fly is a very small black fly which has been described as "a low flying miniature cruise missile". The fly is attracted to the Carrots by smell. It lays its eggs in the soil adjacent to the Carrots. The eggs hatch and the grubs burrow into the roots. The result is a mess, with grub tunnels all through the carrot.
    • It stays in the ground over winter gorging itself on your Carrots, pupates and lays eggs in early spring. Eggs will ideally be laid near to Carrots but Parsley, (and Cow Parsley), Celery and Parsnips, are also affected. After the spring generation have hatched they lay eggs in June and July and this generation hatches and matures in enough time to have another frenzy of egg laying August-September time.
    • This insect pest also loves parsley, parsnips, celery and celeriac. Attacks are particularly bad in old established gardens where the population builds up each year. Most carrot pests and diseases are soil-borne and can be controlled by crop rotation.
    • Adult flies, attracted by the smell of carrots, lay their eggs at ground level so the little white grubs can hatch out and tunnel into the carrot roots. Therefore vulnerable young seedlings die and the foliage of large seedlings turn bronzy red and the plants weaken.
    • There are usually two, sometimes three, generations of carrot fly in a year. The first and worst attack occurs mid-May and mid-June; subsequent attacks are in Autumn and in Winter in mild seasons.
    • The Carrot Fly is low flying and therefore can be prevented from laying its eggs by physical barriers such as polythene.
    • Surround the carrots with a 60 cm high barrier of clear polythene film or fine netting nailed to canes, making sure there are no gaps at ground level. These barriers should be no more than 100cm wide. In dry months water the carrots if they appear to get dry because of the barrier.
    • The later generation feeds on carrot roots left in the soil in Autumn and early Winter. Grubs pupate in the soil, and hatch out as the first generation next Spring.
    • Other practical tips include sowing early carrots before mid-March and main crop towards the end of May or mid-June. Sow very thinly to minimise the need for later thinning. You can try growing carrots under fine net film, very similar to mosquito netting, making sure there are no gaps at ground level.
    • Inter-planting onions or garlic in the carrot beds may also ward off the villainous flies. Mix carrot seed with feathery leaved annual flowers when sowing.
    • Compost and wood ashes will also scare off not only carrot flies but carrot weevils, wireworms, and other carrot pests. Probably the best organic way to get rid of pests is to soak the bed once a week with a thin mixture of wood ashes and water using a watering can.
    • Some chemical control can be achieved through dusting the rows before sowing in Spring with bromophos, phroxim or pirimphos-methyl dust. Protection of late crops can be done by spraying with half strength liquid pirimphos-methyl in early August.
    • Grow varieties with partial resistance. "Fly away" and "Sytan" have some resistance and the old fashioned mainly white fodder carrot is also fairly resistant.
    The Problem Possible Cause Action
    Carrot twist around each other Plants too close together. Thin carrots to 2 inches apart when they are small.
    Carrots rotted or have large white "eyes". Overwatering. Water less frequently. Do not plant the carrots in heavy soil.
    White growth on leaves. Powdery mildew. Use fungicide if extensive damage. Sulphur may help.
    Thin spindly growth. Competition from weeds/other plants. Control the opposition.
    Rotted roots. White fungus on soil surface and on root. Small brown oval honey coloured sclerotia in fungal growth. Southern blight of white mould. Caused by Sclerotium rolfsii. Avoid planting in infested soil. Nitrogen rich fertiliser may help.
    Roots with surface tunnels filled with rusty mush. Stiff white maggots visible but nothing apparent above ground. Carrot root fly. Lays its eggs in the crown of carrots. Read more here. Peel off damaged area before using. Harvest carrots as soon as possible. Do not store carrots in ground through winter. Use a soil insecticide to control maggots at planting.
    Roots hairy, forked or mis-shaped. Root knot nematode. Overwatering, roots in contact with fertiliser pellets or fresh manure. Hard soil or rocks. Overcrowding. Rotate. Remove rocks. Thin carrots early.
    Carrots fail to emerge. Soil crusting. Soil temperature too high. Seedling pests. Maintain uniform soil temperature and moisture until seedlings appear. Do not plant too deeply.
    Yellowed, curled leaves. Stunted plants. Leafhoppers. Use insecticidal soap.
    Brown spots on leaves or roots. Leaf blight. Avoid planting in infested soil. Nitrogen fertiliser could help.
    Tiny holes on leaves. Flea beetles. Control weeds. Use rotenone with insecticidal soap.
    Inner leaves yellowed; outer leaves reddish purple, roots stunted and bitter. Aster yellows (mycoplasma disease). Remove affected plants. Control weeds. Use insecticide.
    Green root tops. Roots exposed to sunlight. Cover exposed roots with soil or mulch.
    All top and no roots Planted too close together. Excessive nitrogen. Thin out early. Go easy on the fertiliser


    La parte edibile della carota - che si coltiva due volte l'anno - è la radice (sviluppata a cono rovesciato): le carote precoci vengono raccolte dopo circa quattro mesi mentre le tardive ne richiedono circa sei. In base al tempo di coltivazione la loro lunghezza può variare da un minimo di 3 cm a un massimo di 20 cm.
    L'uso in cucina della carota è svariato; può essere utilizzata per preparare puree, succhi, minestre, dolci ecc., ma anche cruda in insalata. Ad una temperatura di 0 °C ed un'umidità percentuale tra 90-95 si può conservare per diversi mesi mantenendo inalterate tutte le sue proprietà organolettiche. Se cotta al vapore o consumata cruda conserva ugualmente ogni sua proprietà.
    La parte centrale color porpora del fiore bianco viene usata dagli artigiani della miniatura.
    Dai suoi frutti si ricava un olio aromatico che viene usato per la fabbricazione di liquori.
    La carota è molto usata in cosmesi perché antiossidante e ricca di betacarotene, perciò stimola l'abbronzatura prevenendo la formazione di rughe e curando la pelle secca e le sue impurità; la sua polpa è un ottimo antinfiammatorio molto adatto a curare piaghe, sfoghi cutanei e screpolature della pelle.
    La carota è molto indicata per la cura delle affezioni polmonari e nelle dermatosi; quale gastro-protettore delle pareti dello stomaco è un ottimo antiulcera.
    Fra le altre molteplici proprietà curative, la carota ha quelle di prevenire l'invecchiamento della pelle, facilitare la secrezione del latte nelle puerpere, tonificare il fegato, regolare il colesterolo.
    Altri benefici riconosciuti sono la facilitazione della diuresi, la tonificazione dei reni, l'innalzamento della emoglobina, la regolazione delle funzioni intestinali. Infine, favorisce la vista portando sollievo ad occhi stanchi ed arrossati.

    Nomi comuni
    • cepo bianco;
    • pastinaca;
    • gallinaccio;
    • carota selvatica;
    • cima piuda.

    Nomi regionali
    Campania: pastenàca
    Emilia-Romagna: pastenega, caròta;
    Lombardia: carotula;
    Puglia: pastanaca, caraut;
    Sardegna: fortinàja;
    Toscana: carrota, pistinega.
    .
    Alcuni dati commerciali rilevati il 17.07.2009
    • Dati dettagliati di vendita:
    - nord: 1,35 €/kg;
    - centro: 1,25 €/kg;
    - sud: 1,10 €/kg;
    - media nazionale: 1,25 €/kg.

    • Prezzo medio settimanale:
    - origine: 0,21 €/kg;
    - ingrosso: 0,56 €/kg.

    • Prezzo medio periodico:
    - ultimi 15 giorni: 1,29 €/kg;
    - grande distribuzione: 1,22 €/kg;
    - negozio specializzato: 1,40 €/kg;
    - mercato: 1,24 €/kg;
    - prezzo più alto (Cremona: negozio specializzato): 3,20 €/kg;
    - prezzo più basso (Milano: grande distribuzione): 0,69 €/kg.


    Ambiente pedologico favorevole (limitatamente alla rizosfera)
    • tessitura: sabbioso (85 - 95% di sabbia);
    • drenaggio: l'acqua deve essere rimossa dal suolo prontamente senza il verificarsi, durante la stagione vegetativa, di eccessi di umidità limitanti lo sviluppo della coltura;
    • profondità utile: 50 cm;
    • pH: 6-7;
    • falda: 60-80 cm di profondità;
    • salinità: moderatamente tollerante 3-5 mS/cm.

    Ambiente climatico favorevole
    • temperatura minima: con radice già ingrossata tollera i -3° C in inverno;
    • temperatura ottimale di accrescimento: 13-16° C;
    • temperatura massima: oltre 35° C cessa l'attività vegetativa;
    • umidità del terreno: mantenere valori costanti di umidità ed evitare stress idrici (umidità in eccesso ed in difetto).

    Rotazione
    L’avvicendamento colturale è una pratica necessaria al fine di evitare una ridotta crescita delle piante dovute ad un complesso di cause denominate “stanchezza del terreno”.
    Il ristoppio non è consigliabile, così pure fra due colture successive deve intercorrere un intervallo di due anni nel caso non si siano registrati attacchi di nematodi; oppure occorre osservare un intervallo di tre anni di altre colture.
    Si consiglia di evitare la successione con barbabietola, cipolla e con altre ombrellifere. Buoni risultati si hanno quando la coltura segue cereali, radicchio, melone.

    Preparazione del terreno
    Si consiglia una accurata sistemazione del terreno per facilitare lo sgrondo dell’acqua.
    Si consiglia un’aratura effettuata a 35-40 cm di profondità; che può essere convenientemente sostituita da una vangatura a 30-35 cm qualora l’aratura sia stata effettuata alla coltura precedente.
    In prossimità della semina, il terreno dovrà essere finemente sminuzzato. Si consiglia di effettuare la concimazione organica alla coltura precedente per evitare che l’eccessiva concentrazione di azoto ammoniacale determini malformazioni dei fittoni.
    Una varietà di carota molto speciale è quella del Salento chiamata localmente Pestanaca (anche: Pistanaca o Pastinaca).
    Questo gustoso ortaggio salentino, facilmente riconoscibile per i suoi caratteristici colori, è particolarmente legato a Tiggiano ed in particolare al suo Santo Patrono: S. Ipazzio (vescovo originario dell’Asia Minore); è proprio tra il 18 e il 19 gennaio, quando la pistanaca raggiunge una buona maturazione, che viene festeggiato il santo orientale e tutte le specialità locali, tra le quali le pestanache, le quali vengono vendute sui banchi della fiera mattutina. Da qualche anno, la proloco di Tiggiano, si impegna a promuovere la pestanaca, vero simbolo della gastronomia tiggianese, con concorsi, mostre e dimostrazioni culinarie.
    La Pastanaca si mangia generalmente cruda, ben lavata; ha un sapore particolare che cambia da varietà in varietà e modalità di coltivazione. E’ molto ricca di vitamine e proprietà antinfiammatorie, antiossidanti e altre interessanti caratteristiche nutrizionali.

    Pastinaca del Salento align=
    La pastinaca del Salento, un ecotipo di carota pugliese.


    Scelta della tecnica d’impianto
    Si consiglia la scelta del tipo d’impianto in base al materiale di propagazione e al sesto di impianto. Per quanto riguarda il materiale di propagazione, si consiglia l’impiego di seme conciato e con percentuale di germinabilità dichiarata, in modo tale da calcolare con esattezza un numero di piante ad ettaro.
    Si consiglia di effettuare la semina a bande secondo i parametri seguenti parametri:
    • larghezza della banda (cm): 6-7;
    • distanza fra le bande: 25-35;
    • densità (n. piante/ha): 1,4-1,8 milioni;
    • quantità di seme (kg/ha): 2,0-2,5.

    Per anticipare le semine autunnali (novembre-dicembre) e invernali (gennaio-febbraio) è oggi consigliabile l’utilizzazione di una copertura definita soffice con film di PE incolore dello spessore di 0,06-0,07 mm che consente di precocizzare le raccolte di circa 20 giorni. La copertura verrà rimossa quando il film è sollevato dall’apparato fogliare o quando si notano i primi danni da elevate temperature (scottature).
    Con l’impiego della copertura si consiglia di effettuare la semina entro solchetti, della profondità di circa 10 cm e della larghezza di 15 cm, formati al momento della semina. In questo caso il terreno è sistemato a prose aventi larghezza di 1,8-2 m.

    Fertilizzazione
    I valori di asportazione per la carota sono:
    • N: 4,0 Kg/1 t di prodotto raccolto t.q.;
    • P2O5: 1,7 Kg/1 t di prodotto raccolto t.q.;
    • K2O: 6,6 Kg/1 t di prodotto raccolto t.q.;
    • Mg 0,6 Kg/1 t di prodotto raccolto t.q.;
    • Ca 3,0 Kg/1 t di prodotto raccolto t.q.;

    CONCIMAZIONE FOSFO-POTASSICA
    Gli apporti di P2O5 e K2O devono essere calcolati in base alle asportazioni presunte.
    Per valutare la dotazione del terreno bisogna riferirsi ai sesti d’impianto, alle densità d’investimento consigliati ed ai valori di asportazione nella coltura della carota sopra riportati, considerando che la carota è una coltura mediamente esigente in fosforo.
    Tali quantità non possono comunque superare i limiti massimi fissati in relazione alla dotazione di questi elementi nel terreno e che sono appresso indicati.
    Nella tabella che segue, infatti, sono indicati gli apporti massimi e le epoche di distribuzione consigliate in rapporto all'elemento fertilizzante ed alla sua dotazione nel suolo.

    Dotazione del terreno Elemento fertilizzante Apporti massimi (Kg/ha) Epoca di distribuzione
    Bassa

    P2O5
    K2O
    250
    300
    Pre-semina
    Pre-semina
    Normale

    P2O5
    K2O
    100
    150
    Pre-semina
    Pre-semina
    Elevata

    P2O5
    K2O
    50
    100
    Pre-semina
    Pre-semina


    CONCIMAZIONE AZOTATA
    Le quantità di N da apportare sono pari alle asportazioni della presunta produzione. Tuttavia, è consigliabile non superare il valore di 120 Kg/ha, quantità che deve essere frazionata a partire dalla semina o trapianto.

    COEFFICIENTE TEMPO
    Tale coefficiente indica la quota (su base annua) di elementi nutritivi che si rendono disponibili per la coltura dalla mineralizzazione di matrici organiche (sostanza organica del terreno, ammendanti). Per la carota, coefficiente tempo è uguale a 0,5. Si ricorda che deve essere utilizzato per stimare le disponibilità effettive per la coltura di N, P2O5 e K2O, derivanti dall’impiego di ammendanti organici.

    Composition and energetic value
    (in percent per 100 gr of product - Istituto Nazionale della Nutrizione):
    • Edible part 95%
    • Water 91,6 g
    • Proteins 1,1 g
    • Lipids 0 g
    • Glucids disposables 7,6 g
    • Fiber 3,1 g
    • Energy 33 kcal
    • Sodium 95 mg
    • Potassium 220 mg
    • Iron 0,7 mg
    • Calcium 44 mg
    • Phoohorus 37 mg
    • Niacine 0,7 mg
    • Vitamin C 4 mg
    • Vitamins B1, B2, PP, E, D
    • Vitamin A e provitamina A.


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