 Cyst are thought to have evolved the sedentary lifestyle independently.  They spend most of their active lives within plant roots, feeding on greatly modified host cells.  Cyst nematodes represent a large group of plant parasites comprising 75 or more species.  Etymology  Globodera  Punctodera Heterodera  Cactodera heteros = other, different  Dolichodera deras = skin, body wall  Afenestra Globodera  Brevicephalodera globus = round deras = skin, body wall  Cereal cyst Heterodera avenae  Soybean cyst nematode H. glycines  Pigeon pea cyst nematode H. cajani  Maize cyst nematode H. zeae  Clover cyst nematode H. trifolii  Brassica cyst nematode H. cruciferae

 Potato cyst nematode . Globodera rostechiensis  1859 – First report of a cyst nematode from Germany, as causal organism of “Rubenmuditkeit” (Beet tiredness)  1871 – Schmidt named it Heterodera schachtii . Other forms of cyst nematodes discovered on pea, potato, cereals - mostly in Germany  1940 – Franklin separated five species . H. schachtii, H. goettingiana, H. rostochiensis, H. major, H. punctata  Round cysts transferred to Globodera  Heterodera . Mature female and Cyst ▪ Lemon-shaped with short neck and terminal cone (vulval cone), turning into a hard wall, brown or black in colour, vulva terminal, anus dorsally sub-terminal, vulval fenestration present, ambifenestrate or bifenestrate, underbridge and bullae often present, most eggs retained inside the body, some may be laid in gelatinous matrix . Male ▪ About 1 mm, vermiform, stylet and oesophagus well-developed, tail end twisted, without bursa, spicules robust, gubernaculum simple. . Second-stage juvenile ▪ Body slender, about 400-500 µm long, cephalic sclerotisation and stylet robust than in root-knot nematode, oesophageal glands overlap intestine ventrally, tail with a prominent hyaline portion

Signs Lemon Bodies

Cysts on Roots More Cysts

Domain: Eukaryota Kingdom: Metazoa Phylum: Nematoda Class: Order: Family: Genus: Heterodera spp.  Sedentary endoparasite  Cyst containing eggs remain in soil during off-season  Mostly hatching occurs in response to host root exudates  Infective stage – Second-stage juvenile  Prefer meristematic zone for penetration  Establish special feeding areas (Syncytia) in vascular tissues  Further grow to adults, body changes from vermiform to lemon-shaped gradually, posterior part emerges out of root  Adult males become vermiform, are coiled inside J4 cuticle, and finally come out into soil after rupturing cuticle.  Females lay eggs inside their body, turn brown (cyst) and fall into the soil  Major differences from Root- knot nematode No spike tailed stages Stylet present in J3 and J4 Posterior portions of J4 and females protrude out of roots Reproduction usually sexual Egg laying inside the body of female Female forms cyst after egg laying

 J2 become sedentary after penetration, head located near vascular tissues  Enzymatic secretions lead to the formation of syncytia  Syncytium involves xylem, phloem, pericycle, endodermis  Partial cell wall dissolution takes place to result in a big multicellular cytoplasmic mass (syncytium)  First report from Germany by Kuhn in 1874  Nomenclature changed from Heterodera schachtii – . H. schachtii subsp. major – H. major – H. avenae (Wollenweber, 1924)  First report from India by Vasudeva in 1958 from Rajasthan  Distribution • Europe, Australia, Russian states, India, Pakistan . India ▪ • Rajasthan, Haryana, Delhi, Himachal Pradesh, Jammu & Kashmir, Madhya Pradesh, Punjab, Uttar Pradesh

 Hosts . Wheat, Barley (Molya disease) . Oats  Lemon-shaped cyst, each containing ca. 400 eggs formed during march/April, remain dormant in soil till November/December Hatching coincides with wheat sowing (Nov/Dec) at 16-18 C Root exudates do not play any role in hatching Only 50% eggs hatch in first year White females can be seen on roots during Jan/Feb  Stunted growth in patches  Chlorosis when crop is 1-2 months old  Reduced tillering  Culms become thinner and weaker  Earheads fewer and bear fewer grains  Roots become bushy, having swellings at the sites of penetration  White glistening females appear during Jan/Feb on the swellings  Maize cyst Nematode, Heterodera zeae . 1st reoprted from India in 1971. . Prevelent through the country in maiz producing areas.  Rice Cyst Nematode , . 1st reported from India in 1978. . Restricted in the area of Goa and Kerala.  Sugarbeet Cyst Nematode : Heterodera hachachetii  Alfalfa cyst nematode : Heterodera medicaginis  Tobacco Cyst Nematode : Heterodera tabacum  Barley Cyst Nematode : Heterodera filipjevi  Pearl cyst Nematode : Heterodera gambiensis  Pea Cyst Nematode : Heterodera goettingiana  Chick Pea Cyst Nematode : Heterodera rosii  Cyst Nematode : Heterodera ciceri  Sugarcane Cyst Nematode :  Cacti Cyst Nematode: Heterodera cacti  Pegion Pea Cyst Nematode : Heterodera cajani  Preferred Scientific Name . Globodera rostochiensis (Wollenweber, 1923) Skarbilovich, 1959

 Preferred Common Name . yellow potato cyst nematode  Denmark: kartoffelal; kartottelcystenematod  Finland: peruna-ankeroinen  Germany: Aelchen, Goldfarbenes Kartoffelzysten-; Aelchen, Kartoffel-; Nematode, Kartoffel-  Iran: nematode sibsamini  Italy: Anguillula della patata  Netherlands: Aardappel cystenaaltje  Norway: potetcystenematode  Sweden: potatiscystnematod Domain: Eukaryota Kingdom: Metazoa Phylum: Nematoda Class: Secernentea Order: Tylenchida Family: Heteroderidae Genus: Globodera Species: rostochiensis  Globodera . Mature female & Cyst ▪ Spherical with a short neck, terminal portion not forming a cone, vulva terminal, vulval fenestra circumfenestrate, underbridge, bullae rarely present, anus dorsally sub- terminal, no anal fenestra . Male & Second stage juvenile ▪ As in Heterodera 1.They are 1mm long roundworm belonging to genus Globodera, comprising around 12 species. • They live on plants of Solanaceae family(e.g., Potato, Tomato). Potato Cyst Nematode(Eel Worms)

 They are 1mm long roundworm belonging to genus Globodera, comprising around 12 species.   The major hosts of G. rostochiensis are restricted to the Solanaceae, in particular potato, tomato and aubergine.

 A number of weeds in the Solanaceae are also hosts. . Datura tatula, Physochlaina orientalis, Saracha jaltomata etc.  Eggs of Eel nematode hatch in presence of Solanoeclepine-A. . This is secreted by roots of solanaceous plants and hence the larva establishes a feeding site  G. rostochiensis is a world wide pest of temperate areas, including both temperate countries and temperate regions of tropical countries, . for example India’s Nigrilis region.  PCN is considered to have originated from the Andes region of South America, from where it spread to Europe with potatoes.  The cyst which adheres to host roots, tubers and to soil particles during transportation gives rise to new infestations.  Cysts are also successfully spread by wind dispersal, sand storms too.  Rain which causes flooding and water to run off fields into trenches or irrigation channels also redistributes cysts into adjoining areas.  Eggs: . Eggs of G. rostochiensis are always retained within the cyst body and no egg sacs are produced. . The eggshell surface is smooth and no microvilli are present.  Females: . Females emerge from the root cortex about one month to six weeks after invasion by the second-stage juveniles. . They are pure white initially, turning golden yellow on maturation. . Mature females are approximately 500 µm in circumference without a cone. . The cuticle of the female sometimes has a thin subcrystalline layer. . Head bears one to two annules and the neck region has numerous tubercules and head skeleton is hexaradiate and weak. . Stylet is divided equally in length between the conus and the shaft. . Important diagnostic feature is the backward slope of the stylet knobs.  Cyst: . Cysts contain the eggs, the progeny for the next generation, and are formed from the hardened dead cuticle of the female. . Newly produced cysts may still show an intact vulval basin but older cysts, particularly those which have been in the soil for many seasons, lost all signs of their genitalia with only a hole in the cuticle to show the position of the fenestral basin.  Males: . The male is vermiform in shape with a short tail and no bursa. . On fixation, the body assumes a curved shape with the posterior region twisted at a 90 degree angle to the remainder of the body. . There are four incisures in the mid-body i.e. three bands which terminate on the tail. . The rounded head is offset and bears 6-7 annules. . The head is strongly developed having a hexaradiate skeleton. The cephalids are located at body annules 2-4 and 6-9, respectively. . The single testis fills half the body cavity. The paired spicules are arcuate and end with single tips. . The gubernaculum is around 10 µm in length and 2 µm in thickness and lies in a position dorsal to the spicules.  Juveniles: . 2nd-stage juvenile hatches from the egg, the first moult taking place within the egg. . Juvenile, like the male, is vermiform with a rounded head and finely tapered tail. . Hyaline portion of the tail represents about two thirds of its length. . Lateral field has four incisures in the mid-body region reducing to three at the tail terminus and anterior end. . Head is slightly offset and bears four to six annules and head skeleton is well developed and hexaradiate in form. . Cephalids are located at body annules 2-3 and 6-8, respectively. . Stylet is strong, the conus being about 45% of the total length.

 For both susceptible and resistant varieties . . Female individual swell up and appear as cyst on the surface of the roots, each containing upto 400 eggs. . The eggs can survive for up to 20 years inside these cysts. Mechanical damage to root system Low and medium Growth retardation population density For both Susceptible and Resistant Very high population Mechanical damage varieties density to root system

Female individual swell up and appear as cyst on the surface of the roots, each containing up to 400 eggs. The eggs can survive for upto 20 years inside these cysts. Leaves : abnormal colours Leaves : wilting Roots : cysts on root surface Roots : reduced root system Vegetative organs : surface cracking Whole plant : dwarfing Whole plant : early senescence  Eggs contained within cysts are the persistent stage of the life cycle; new cysts contain around 500 eggs.   Some eggs are able to survive within the cyst for as long as 30 years, although by this time very few are viable.

 Hatching in water is normal, especially within the 'hatching season' when most of the environmental factors are stable.

 Hatching increased by the stimulus of a hatching factor, found in host root diffusate. . This appears to affect the permeability of the eggshell lipoprotein membrane.

 Many workers have studied the hydration of second-stage juveniles.  Other factors affecting hatching are . soil moisture . aeration and pH . soil temperature or the rate of heat accumulation ▪ optimum temperature for the hatch of G. rostochiensis is about 15°C.  The infective juveniles, penetrate the host root just behind the root tip.  From this point the juveniles move up or down the root until they receive a specific signal, probably of a chemical nature, to set up a feeding site in the form of a syncytium.  Infective second-stage juveniles that- . penetrate the pericycle cells of the plant are more likely to become males, whereas . those that penetrate the procambial cells tend to become females.  Within a few hours of settling, the juvenile probes the selected cell, inserts its stylet into it while remaining motionless for several hours; the stylet is then withdrawn and re-inserted into the same cell.  A secretory product from the oesophageal glands is injected via the stylet into the selected cell.

 The initial syncytial cell (ISC) is now altered to provide large amounts of nutrients to the developing nematode.

 The syncytium undergoes major changes e.g. . lysis of inner cell walls . formation of cell wall ingrowths next to plant conductive tissue . appearance of numerous lipid bodies and . enlargement of now amoeboid nuclei  The life cycle takes approximately 45 days, during which time . Males moult and become vermiform, leave the host root and fertilize as many females as possible before dying about 10 days or so after first leaving the root. . Females during this time become saccate and their posterior ends have protruded through the root cortex, ready for mating.

 Globodera spp. do not produce egg sacs or form a gelatinous mass into which eggs are deposited. However, it is known that pheromones are secreted which attract males.  Natural Dispersal (Non-Biotic) . Wind lifting and spreading cysts in dry soil and plant debris from one area to another. . Run-off flood water from infested areas can pose a threat as dry cysts float and can be carried some distance from the original source to start new infestations in local situations.

 Vector Transmission (Biotic) . Cyst nematodes are capable of passing through the digestive tract of farm and are excreted intact in a viable condition ready to begin a new infestation. . Soil debris transported on hoofs can move cysts from one area to another.

 Accidental Introduction . Probably the most likely cause of new introductions to different countries has been unintentional and has come with the advent of trade and travel.  Potato cyst nematodes cause extensive damage depends on the presence of eggs/g of soil. For example- . Yield losses of 20, 50 and 90% were obtained with population densities of 9, 28 and 128 eggs/g soil, respectively. . Yield losses of 6.25 t/ha per 20 eggs/g soil are recorded.  To prevent further spread of PCN, several methods are used. . legislation on the movement of seed potatoes, . nursery stock, . flower bulbs and . soil 1. Check that machinery is thoroughly clean and free from plant debris.

2. Do not return soil to fields as it may cause infestation of potato cyst nematode to spread.

3. Clean soil from potato tubers and have the soil tested to be sure of non-transference of potato cyst nematode.

4. Make sure that laboratories that test soil for potato cyst nematode are properly.

5. Grow susceptible and resistant varieties of potato alternately, thus reducing the possibility of selecting a highly virulent or new pathotypes.  Crop rotation  Host resistance  Trap cropping  Soil solarization  Biological control  Chemical control . Fumigant nematicides apply several weeks before planting to avoid phytotoxicity. . Non-fumigant nematicides are most effective when used in granular form and at 15 cm. below the soil surface Thanks