Chicory

Description

Common chicory, Cichorium intybus, is a perennial herb in the family Asteraceae grown for use as a salad green. Generally, chicory plants have an erect growth habit with numerous lanceolate (lance shaped) leaves branching off of the erect stems. The basal leaves can reach 25 cm (9.8 in) in length and are spatulate (spoon-shaped) and may be green or red in color. There are two rows of bracts (modified leaves) on the stems, the inner are longer and erect and the outer are shorter and spreading The foliage is commonly covered in hairs. The plant produces bright blue or sometimes pink or white flowers which are 2–4 cm (0.79–1.6 in) in diameter. Chicory can grow to a height of 0.6–1.2 m (2.0–3.9 ft) and is usually grown as a biennial. Chicory may also be referred to by variety and these include Common chicory, Italian dandelion, Witloof, Belgian endive and radicchio. Chicory likely originates from the Mediterranean.


Uses

Chicory is predominantly grown for its leaves which are used as salad greens or cooked. The witloof variety is also grown for its root which can be ground and used as a coffee substitute.


Propagation


Basic requirements
Many types of chicory are available for the home garden and the chosen variety depends ultimately on its desired use. Radicchio types are grown for their leaves whereas witloof types may be grown for their roots and leaves. Chicory is a cool season crop and radicchio varieties require cool temperatures to produce heads. Plants will grows best in fertile, well draining soils with a pH between 6.5 and 7.2 and should be positioned in full sun.

Planting
Chicory can be direct seeded or started indoors for transplanting. If started indoors, seeds should be sown in a sterile seed starting mix by planting to a depth of 0.6 cm (0.25 in). Thin the seedlings when they have 3 to 4 sets of true leaves. The seedlings are ready for transplanting when they are about 5 to 6 weeks old and have 5 or six mature leaves. Seedlings should be hardened prior to transplanting by gradually increasing their exposure to outdoor conditions. Space seedlings 20 to 23 cm (8-9 in) apart allowing 20 cm (8 in) between rows. Directly seeded plants should be thinned to this spacing.

General care and maintenance
Plants should be protected from frosts with row covers or fabric to prevent damage. The plants will benefit from a layer of organic mulch such as grass clippings or leaves which will help to suppress weeds while conserving moisture in the soil. Plants should be kept moist during growth to prevent the development of bitter tasting leaves. Chicory generally requires 1 to 2 inches of water a week but this will depend on the type of soil and the prevailing climatic conditions.

Harvesting
Radicchio varieties should be harvested when the leaves have reached their full size. Harvesting should not be delayed as it results in the leaves developing a bitter flavor. Cut the head from the plant using a sharp knife to cut through the stem just below the head. Witloof varieties grown for leaves should be harvested while the leaves are young and tender. If the plants are being grown for their roots then they should be pulled from the soil just before the last frost date. The leaves should be trimmed to about 2.5 cm from the crown and the roots should be trimmed to a uniform size. Store the trimmed plants at 0°C (32°F) for 5 to 7 weeks before forcing.

Forcing
Forcing is the term used to describe the process by which witloof chicory varieties are forced to produce new growth in winter. The forcing process is commonly carried out by transplanting the plants into sand filled boxes or buckets which are then stored in a frost free place such as a glasshouse, shed or basement where temperatures are between 10 and 15.55°C (50-60°F).The chicory plants should be planted in the sand, leaving the crown exposed and then either kept in darkness if in a basement or covered if in a glasshouse. It is important that no light is able to reach the plants. The plant will begin to produce a tightly packed head of leaves called a chicon. Chicons are ready for harvest within 3-5 weeks.


References

CABI Crop Protection Compendium. (2010). Cichorium intybus datasheet. Available at: http://www.cabi.org/cpc/datasheet/13409. [Accessed 11 November 14]. Paid subscription required.

Hall, M. H. & Jung, G. A. (2008). Forage Chicory. Penn State Extension. Available at: http://pubs.cas.psu.edu/freepubs/pdfs.... [Accessed 11 November 14]. Free to access.

USDA (2003). Chicory. The U.S. Department of Agriculture (USDA). Available at: ftp://ftp-fc.sc.egov.usda.gov/IL/graz.... [Accessed 11 November 14]. Free to access.


Common Pests and Diseases

Bacteral soft rot
Erwinia spp.

Symptoms
Water-soaked lesions which expand to form a large rotted mass of cream colored tissue which is liquid underneath; surface of lesions usually crack and exude slimy liquid which turns tan, dark brown or black on exposure to air
Cause
Bacteria
Comments
Bacteria are easily spread on tools and by irrigation water; disease emergence favored by warm, moist conditions; bacteria enter plant through wounds
Management
Chemical treatments are not available for bacterial soft rot, control relies on cultural practices; rotate crops; plant cabbage in well-draining soils or raised beds; only harvest heads when they are dry; avoid damaging heads during harvest

Damping-off
Pythium spp.
Rhizoctonia solani

Symptoms
Poor seedling germination and emergence; dark lesions on stems; withered stem; stems collapsing; brown rotting roots
Cause
Fungi
Comments
Disease emergence in seedlings favored by cool temperatures and waterlogged soils
Management
Plant pathogen-free seed or transplants that have been produced in sterilized soil; apply fungicide to seed to kill off any fungi; shallow plant seeds or delay planting until soil warms

Fusarium wilt
Fusarium spp.

Symptoms
Small water soaked lesions on foliage; drooping and yellowing of leaves
Cause
Fungi
Comments
High temperatures and rainfall promote spread

White mold
Sclerotinia sclerotiorum

Symptoms
Abundant white mycelium (thread-like fungal structures) on any part of plant; Wilting of outside leaves which spreads inwards until whole plant is affected; soft watery lesions on leaves; leaves collapse and lie on soil surface; black fungal structures on infected leaf tissue and soil surface
Cause
Fungi
Comments
Common in cool moist regions on a variety of crops; fungus can survive in soil for 8-10 years
Management
Rotate crop to non-hosts (e.g. cereals) for at least 3 years; control weeds; avoid dense growth by planting in adequately spaced rows; disease significantly reduced by application of fungicides immediately after thinning plants; plow soil deeply

Anthracnose
Microdochium panttonianum

Symptoms
Small circular or irregularly shaped dry spots which are gray to straw in color on leaves; a high number of spots may cause the leaf to die; lesions may coalesce to form large necrotic patches causing leaves to turn yellow and wilt; lesions may split or crack in dry centers
Cause
Fungus
Comments
Fungus overwinters on leaf debris and on related weeds; disease emergence is favored by moist, warm conditions
Management
Control of disease depends on sanitary practices; treat seeds with hot water prior to planting; rotate crops; plant in an area with good soil drainage; remove all cruciferous weeds which may act as a reservoir for the fungus

Bottom rot
Rhizoctonia solani

Symptoms
Small red to brown spots on lower leaves, usually on underside of midrib which may expand rapidly causing the leaves to rot; amber colored liquid may ooze from leaf lesions; as stems rot, head of lettuce becomes slimy and brown and collapse; a tan or brown mycelial growth may be visible in infected tissue
Cause
Fungus
Comments
Fungus survives on crop debris in soil; disease emergence favored by warm, wet weather
Management
Disease is most effectively managed by combining cultural control with fungicide application; plow soil before planting; rotate crops regularly; avoid irrigation close to harvest; plant varieties with an erect growth habit to reduce leaf contact with soil; apply appropriate foliar fungicides

Downy mildew
Bremia lactucae

Symptoms
Young leaves drying up and dropping off; older leaves developing a papery texture; white fuzzy mold on the underside of leaves
Cause
Fungus
Comments
Disease favors cool, moist conditions; can be spread via infected seed; fungus survives in plant debris and in wild lettuce plants
Management
Disease is controlled primarily by planting resistant varieties and/or by applying appropriate fungicides

Septoria blight
Septoria lactucae

Symptoms
Small, irregularly shaped chlorotic spots on oldest plant leaves which enlarge and turn brown and dry out; lesiuons may fall out of leaves creating holes; leaf spots may have chlorotic halos; if plant is severely infected, lesions may coalesce forming large necrotic patches, wilting leaves and plant death
Cause
Fungus
Comments
Fungus survives in infected seed and in crop debris; disease spreads in humid or wet conditions; can be spread by splashing water; wild lettuce is an important overwintering site for the fungus
Management
Plant pathogen free seed; plant in areas where Septoria is uncommon; ideal planting sites are in regions with low rainfall; hot water treatment of seeds prior to planting may help reduce levels of disease

Aphids (Green peach aphid, Lettuce aphid, Plum aphid)
Myzus perisicae
Nasonovia ribisnigri
Brachycaudus helichrysi

Symptoms
Small soft bodied insects on underside of leaves and/or stems of plant; usually green or yellow in color, but may be pink, brown, red or black depending on species and host plant; if aphid infestation is heavy it may cause leaves to yellow and/or distorted, necrotic spots on leaves and/or stunted shoots; aphids secrete a sticky, sugary substance called honeydew which encourages the growth of sooty mold on the plants
Cause
Insect
Comments
Aphids will be visible on the leaves; small, rounded green to pink insects; distinguishing features include the presence of cornicles (tubular structures) which project backwards from the body of the aphid; will generally not move very quickly when disturbed
Management
If aphid population is limited to just a few leaves or shoots then the infestation can be pruned out to provide control; check transplants for aphids before planting; use tolerant varieties if available; reflective mulches such as silver colored plastic can deter aphids from feeding on plants; sturdy plants can be sprayed with a strong jet of water to knock aphids from leaves; insecticides are generally only required to treat aphids if the infestation is very high - plants generally tolerate low and medium level infestation; insecticidal soaps or oils such as neem or canola oil are usually the best method of control; always check the labels of the products for specific usage guidelines prior to use

Darkling beetles
Eleodes sp
Blapstinus spp.
Caelus spp.

Symptoms
Feeding damage on stems; death of seedlings; seeds dug up; insect is a dull blue-black or brown beetle about 0.6 cm (0.52 in) long; tips of antennae are often enlarged, resembling a club
Cause
Insect
Comments
Beetles are generally active at night; during the day beetles hide in organic debris
Management
Ditches filled with water can prevent spread of beetle to/from adjacent fields; remove all weeds from garden borders; if beetle is problematic then appropriate insecticides can provide control; insecticides are usually in the form of baits

Flea beetles
Epitrix spp.
Phyllotreta spp.

Symptoms
Small holes or pits in leaves that give the foliage a characteristic “shothole” appearance; young plants and seedlings are particularly susceptible; plant growth may be reduced; if damage is severe the plant may be killed; the pest responsible for the damage is a small (1.5–3.0 mm) dark colored beetle which jumps when disturbed; the beetles are often shiny in appearance
Cause
Insect
Comments
Younger plants are more susceptible to flea beetle damage than older ones; older plants can tolerate infestation; flea beetles may overwinter on nearby weed species, in plant debris or in the soil; insects may go through a second or third generation in one year
Management
In areas where flea beetles are a problem, floating row covers may have to be used prior to the emergence of the beetles to provide a physical barrier to protect young plants; plant seeds early to allow establishment before the beetles become a problem - mature plants are less susceptible to damage; trap crops may provide a measure of control - cruciferous plants are best; application of a thick layer of mulch may help prevent beetles reaching surface; application on diamotecoeus earth or oils such as neem oil are effective control methods for organic growers; application of insecticides containing carbaryl, spinosad, bifenthrin and permethrin can provide adequate control of beetles for up to a week but will need reapplied

Leafminers
Liriomyza spp

Symptoms
Thin, white, winding trails on leaves; heavy mining can result in white blotches on leaves and leaves dropping from the plant prematurely; early infestation can cause fruit yield to be reduced; adult leafminer is a small black and yellow fly which lays its eggs in the leaf; larave hatch and feed on leaf interior
Cause
Insect
Comments
Mature larvae drop from leaves into soil to pupate; entire lifecycle can take as little as 2 weeks in warm weather; insect may go through 7 to 10 generations per year
Management
Check transplants for signs of leafminer damage prior to planting; remove plants from soil immediately after harvest; only use insecticides when leafminer damage has been identified as unnecessary spraying will also reduce populations of their natural enemies

Loopers (Cabbage looper, Alfalfa looper)
Trichoplusia ni
Autographa californica

Symptoms
Large or small holes in leaves; damage often extensive; caterpillars are pale green with a white lines running down either side of their body; caterpillars are easily distinguished by the way they arch their body when moving; eggs are laid singly, usually on the lower leaf surface close to the leaf margin, and are white or pale green in color
Cause
Insect
Comments
Insects overwinter as pupae in crop debris in soil; adult insect id a dark colored moth; caterpillars have a wide host range
Management
Looper populations are usually held in check by natural enemies; if they do become problematic larvae can be hand-picked from the plants; an organically acceptable control method is the application of Bacillus thuringiensis which effectively kills younger larvae; chemical sprays may damage populations of natural enemies and should and should be selected carefully

Thrips (Western flower thrips, Onion thrips)
Frankliniella occidentalis
Thrips tabaci

Symptoms
If population is high leaves may be distorted; leaves are covered in coarse stippling and may appear silvery; leaves speckled with black feces; insect is small (1.5 mm) and slender and best viewed using a hand lens; adult thrips are pale yellow to light brown and the nymphs are smaller and lighter in color
Cause
Insect
Comments
Transmit viruses such as Tomato spotted wilt virus; once acquired, the insect retains the ability to transmit the virus for the remainder of its life
Management
Avoid planting next to onions, garlic or cereals where very large numbers of thrips can build up; use reflective mulches early in growing season to deter thrips; apply appropriate insecticide if thrips become problematic

Slugs & snails (Gray garden slug, Spotted garden slug, Brown garden snail, European garden snail , etc.)
Decoratus reticulatum
Limax maximus
Helix aspersa
Cornu aspersum

Symptoms
Irregularly shaped holes in leaves and stems; flowers and fruit may also be damaged if present; if infestation is severe, leaves may be shredded; slime trails present on rocks, walkways, soil and plant foliage; several slug and snail species are common garden pests; slugs are dark gray to black in color and can range in size from 2.5 to 10 cm (1-4 in); garden snails are generally smaller and possess a rounded or spiral shell
Cause
Mollusc
Comments
Slugs and snails prefer moist, shaded habitats and will shelter in weeds or organic trash; adults may deposit eggs in the soil throughout the season; damage to plants can be extensive
Management
Practice good garden sanitation by removing garden trash, weeds and plant debris to promote good air circulation and reduce moist habitat for slugs and snails; handpick slugs at night to decrease population; spread wood ashes or eggshells around plants; attract molluscs by leaving out organic matter such as lettuce or grapefruit skins, destroy any found feeding on lure; sink shallow dishes filled with beer into the soil to attract and drown the molluscs; chemical controls include ferrous phosphate for organic gardens and metaldehyde (e.g. Buggeta) and carbaryl (e.g Sevin bait) for non-organic growers