Heterodera

identification of cyst nematode (Heterodera and Globodera)

1. Heterodera Cyst Nematode Presented by R MOHANAPRIYA M.Sc. Agri (Plant Pathology) JSA College of Agriculture and Technology

2. Systematic position Phylum : Nematoda Class : Secernentea Order : Tylenchida Suborder : Tylenchina Super family : Tylenchoidea Family : Heteroderidae Sub-family : Heteroderinae Genus : Heterodera Species : Sugarbeet cyst nematode – H. schachtii Cereal cyst nematode - H. avenae Rice cyst nematode - H. oryzicola Pigeonpea cyst nematode - H. cajani Soyabean cyst nematode- H. Glycines Maize/Corn cyst nematode – H. Zeae Clover cyst nematode – H. Trifolii Brassica cyst nematode – H. cruciferae Major hosts : Species are host specific Type of parasitism : Sedentary endoparasite

3. History In the early 1800s, "beet fatigue" was used to describe the decreased sugar beet yields which occurred after repeated planting on the same field. At first, this decrease was believed to be the result of nutrient depletion , but in 1859 the botanist H. Schacht discovered nematode cysts on the roots of affected plants. The sugarbeet cyst nematode ( Heterodera schachtii )was first discovered by schacht in 1859 from Germany as the causal organism of “ rubenmudigkiet ” or “beet tiredness”. Later named as Heterodera schachtii by Schmidt in 1871.

4. Economically important nematode in india Gr. heteros - different , deros - skin, body wall Host specific hard brown cyst wall as compared to soft transparent body wall of other nematodes (female turns into a hard brown cyst enclosing eggs inside)

5. Host range It can infect more than 200 plant species, including sugarbeet , raddish , broccoli,cabbage . It can also survive on weeds. Distribution Widely distributed in all sugar beet growing areas of the world. Today , SBCN is present in forty different countries and seventeen states in the United States, including Washington, Oregon, Utah, and Idaho .

6. Spread SBCN is a soilborne pest, so anything that can move soil will move the nematode. Cysts can be spread by machinery, animals, water and tare soil from harvested beets. In the soil profile, cysts can be found from the surface to 24 inches deep , but the highest numbers are found in the root zone (2 to 10 inches soil depth ).

7. Mature female and cyst - Lemon shaped with a short neck and terminal cone( vulvalcone ) turning into a hard wall cyst brown or black in colour (0.5 to 0.8mm) - Vulva terminal - Anus dorsally subterminal - Vulval fenestration present ( ambifenestrate / bifenestrate ) - Eggs in the body some times in gelatinus matrix - Bullae often present

8. Male - V ermiform - 1mm to 2mm length - Stylet - short in males with rounded basal knobs, more than 0.02mm long in juveniles. -Oesophagus : with well developed median bulb and lobe extending back and overlapping the intestine on all sides -Spicules near the posterior end (robust), gubernaculum present, bursa absent, tail end twisted

9. Second juvenile stage - Slender, juveniles 0.3 to 0.6mm length - 400-500µm long - Cephalic sclerotization - Stylet more robust - Oesophagus overlap intestine ventally - Tail hyaline

10. Life Cycle and Survival - Sedentary endoparasite , - The nematode survives in the soil as cysts that contain eggs and juveniles. Under favorable conditions — warm temperatures (70 to 81 degrees F ) and sufficient soil moisture — and the presence of root exudate from hosts, second-stage-juveniles hatch from eggs, enter the root tissue , and move to cortical tissues where they feed . Several generation in one season

11. Symptoms Fields may be uniformly infested or may have localized areas of infestations. Circular to oval spots where poor plant stands and growth are observed. The pathogen can attack plants of any age, and seedlings or young beets may be killed, resulting in reduced stands. Young plants infected by the disease have elongated petioles and remain stunted until harvest. Leaves of severely affected plant additionally wilt and have pronounced yellowing.

12. Management Sanitation : Tare soil should not be dumped back into fields. Plant SBCN tolerant cultivars which are available, but be aware of their susceptibility to other diseases, including Cercospora and Rhizoctonia root rot. Rotation with non-host crops, including wheat, barley, corn, bean, potato and alfalfa. Three- to four-year rotation is needed in heavily infested fields; rotations with non-host may reduce initial SBCN population by 40-60 percent in a year.

13. Plant trap crops which attract SBCN, but do not allow them to develop and reproduce . Some SBCN-tolerant cultivars of oil seed radish (Defender, Image and Colonel ) and mustard are effective Early planting when soil temperatures are not favorable (< 59 degrees F) for infection by SBCN. Control weeds that are hosts for SBCN in sugar beet and rotation crops. Avoid returning tare soil with SBCN to fields in which sugar beet is grown . Some nematicides may be effective, but are typically difficult to apply and may be uneconomical . Biological seed treatment which utilize spores of Pasteuria nishizawae may help to manage SBCN on tolerant sugarbeet varieties.

14. Globodera Potato Cyst Nematode 1 st reported by Jones 1961 in Nilgiri hills

15. Systematic position Same as Heterodera Common Name Golden nematode, golden potato cyst nematode, yellow potato cyst nematode, golden eelworm Potato – cool climate Hills –summer Plains –winter Sedentory endo parasite Morphology Similar to Heterodera but the cyst is globose , vulva and anus are not on a terminal cone, vulval slit is surrounded by a single, circular fenestra

16. Only one generation in a season and requires potato root exudates for hatching eggs

17. Root knot nematode Meloidogyne

18. Systematic position Phylum : Nematoda Class : Secernentea Order : Tylenchida Suborder : Tylenchina Super family : Tylenchoidea Family : Heteroderidae Sub-family : Meloidogyninae Genus : Meloidogyne Species : M. incognita, M. javanica, M. arenaria, M. hapla M. graminicola , Major hosts : Vegetables , papaya, potato, betelvine , groundnut , carrot ad rice

19. Body: elongated in juveniles (0.5mm in length) and males (1.0-2.0mm in length), typically saccate , spheroid, with a distinct neck in females (0.8 mm long and 0.5mm wide), head skeleton weak. Stylet : strong with rounded knobs in males, more slender in females than in males and juveniles but with strong basal knobs. Oesophagus: with very large median bulb followed by a short isthmus.

20. Female: vulva and anus typically opposite to neck and surrounded by a pattern of fine lines resembling human finger prints called ” perineal pattern ‟; ovaries didelphic , convoluted. Male: tail - short, hemispherical; spicules - robust, very near to the tail terminus, bursa absent.

21. Biology: Meloidogyne spp. are sedentary endoparasites . Second stage juveniles are infective and establish a feeding site (syncytium) involving vascular tissues, endodermis and pericycle cells. The feeding site comprises of 8-12 multinucleate „giant cells‟ . The second stage juveniles start swelling and develop to third and fourth stages. After final moult, males acquire vermiform shape and come out into the soil. Females attain saccate shape and lay eggs in a gelatinous matrix (egg mass ) on the root surface. Reproduction is generally by parthenogenesis and nematode completes 7- 8 generations in a year.

22. Management Cover crops crop rotation flooding and solarization of fields Fumigants (such as 1,3-dichloropropene, methyl bromide and dazomet ) are commonly applied as pre-plant treatments broad-spectrum fumigants, nervous system toxins (including oxamyl and fenamiphos )