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Lecture 5 Classification of Nematodes on the basis of Phytoparasitism 6/14/2014Walia CCSHAU1.

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Presentation on theme: "Lecture 5 Classification of Nematodes on the basis of Phytoparasitism 6/14/2014Walia CCSHAU1."— Presentation transcript:

1 Lecture 5 Classification of Nematodes on the basis of Phytoparasitism 6/14/2014Walia CCSHAU1

2 Habitat Majority (90%) of PPNs attack roots or other below ground plant parts such as tubers, rhizomes, suckers, bulbs etc. – Ectoparasites60% – Endoparasites30% Only a few forms (10%) attack above ground parts such as leaves, stems, buds, inflorescence etc. – Ectoparasites2% – Endoparasites8% 6/14/2014Walia CCSHAU2

3 Parasites of below ground part parts Parasite of below ground plant parts EctoparasitesMigratorySedentary Semi- endoparasites MigratorySedentaryEndoparsitesSedentaryMigratory 6/14/2014Walia CCSHAU3

4 Ectoparasites Spend entire life cycle in soil, all life cycle stages, including eggs in soil Only stylet is inserted into roots, body remains outside A vast majority of ectoparasites feed on root hairs and epidermal cells Not considered very damaging, except for some groups 6/14/2014Walia CCSHAU4

5 Ectoparasites Migratory (Vagrant ectoparsites) – Feed at a particular site very briefly and then move to another site – Remain vermiform, eggs scattered in soil – Examples Awl nematode, Dolichodorus Sting nematode, Belonolaimus Dagger nematode, Xiphinema Needle nematode, Longidorus Stubby root nematode, Trichodorus, Paratrichodorus 6/14/2014Walia CCSHAU5

6 Ectoparasites Sedentary (Sessile) ectoparasites – Feed at a site for long period – Very sluggish in movement – Have coarse striation or annulations on cuticle – Criconematid group having small bodies and long stylets relative to their body fall in this category – May secrete an adhesive plug to fix the stylet into the root – Examples Sheath nematode, Hemicycliophora arenaria Sessile nematode, Cacopaurus pestis 6/14/2014Walia CCSHAU6

7 Semi-endoparsites The anterior portion of the body is embedded into the plant tissues Migratory semi-endoparasites – Remain vermiform – Do not establish a permanent feeding site in plant tissues – Rarely the entire body may be inside the plant tissues – Examples Spiral nematode, Helicotylenchus Lance nematode, Hoplolaimus Stunt or Stylet nematode, Tylenchorhynchus group 6/14/2014Walia CCSHAU7

8 Semi-endoparasites Sedentary semi-endoparasites – Establish a permanent feeding site inside plant tissues – Do not move after infection – Eggs are deposited in masses around the body of females; fecundity is more - about eggs per female – The posterior part of females outside the root becomes swollen to varying degrees Citrus nematode, Tylenchulus semipenetrans Reniform nematode, Rotylenchulus reniformis 6/14/2014Walia CCSHAU8

9 Sedentary Semi-endoparasites Examples – Reniform nematode, Rotylenchulus reniformis – Citrus nematode, Tylenchulus semipenetrans 6/14/2014Walia CCSHAU9

10 Endoparasites Migratory endoparasites – All stages (except egg) can cause infection, and are present in soil initially – Complete the entire life cycle in side plant tissues – Feeding, migration, growth, reproduction, and oviposition take place in plant tissues – Biological activities confined to cortex only; eggs are laid scattered, fecundity around 25 eggs per female – Do not induce any special feeding area – Any stage can leave the roots and come out into the soil due crop senescence of tissue destruction Lesion or Meadow nematode, Pratylenchus Rice root nematode, Hirschmanniella Burrowing nematode, Radopholus 6/14/2014Walia CCSHAU10

11 Migratory Endoparasites 6/14/2014Walia CCSHAU11

12 Endoparasites Sedentary endoparasites – Evolutionary most advanced and most damaging among all PPNs – Only a particular stage (J2) of life cycle infective – Induce special feeding areas, involving vascular tissues – Females become swollen to varying degrees after infection and do not move – Eggs laid in masses either inside the female body or outside in an eggmass – Fecundity is high ( eggs per female) Root-knot nematode, Meloidogyne Cyst nematode, Heterodera, Globodera 6/14/2014Walia CCSHAU12

13 Sedentary Endoparasites 6/14/2014Walia CCSHAU13

14 Parasites of above ground plant parts Specially adapted to feed on leaves, stems, buds, inflorescence etc. May feed ecto- or endoparasitically Do not produce any special feeding area Can crawl up the plant in a thin film of water Eggs are deposited in plant tissues Usually undergo anhydrobiosis at crop maturity or under moisture stress; a particular stage of life cycle only undergoes quiescence Can remain dormant for varying periods, revive upon availability of moisture 6/14/2014Walia CCSHAU14

15 Anhydrobiosis 6/14/2014Walia CCSHAU15

16 Parasites of above ground plant parts Gall forming – Wheat seed gall nematode, Anguina tritici – Leaf gall nematode, Anguina balsamophila Non-gall forming – Stem nematode, Ditylenchus dipsaci, D. angustus – Foliar nematode, Aphelenchoides fragariae, A. ritzemabosi Associates of insects – Pine wood nematode, Bursaphelenchus xylophilus – Red ring nematode, Bursaphelenchus cocophilus 6/14/2014Walia CCSHAU16

17 6/14/2014Walia CCSHAU17

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