Plant Disease Caused by

by Asst. Prof. Pornsuk Chaisuk Kingdom : Animalia Plylum : Nematoda - free living - plant/ parasite Types of nematode >100,000,000 but only 20,000 species were named

Animal nematode 15%

Plant nematode 10% Marine nematode 50%

Free-living nematode 25% Animal and human

- Ascaris lumbricoides พยาธิในลําไส้/พยาธิไส้เดือน - Trichinella spiralis พยาธิเนือหมู - Gnathostoma spiningenum พยาธิตัวจิด - Ancylostoma duodenale พยาธิปากขอ (hookworm) - Wuchereria bancrofti สาเหตุโรคเท้าช้าง Important plant nematodes

- Globodera rostochinensis : potato -> stunt - dipsaci : oat, rye, rice, onion, sugar beet and other bulb plants -> bloat/ swollen - Meloidogyne spp. : tomato, chilli, potato, caroot, okra, soybean, grass and other plants -> gall History of nematode discovery A.D.1656 : Nematode was first discovered after the invention of a microscope by P. borellus. First nematode was Turbatrix aceti ( eel) that free living nematode lived in vinegar. A.D. 1743 : First plant nematode was discovered J.T. Needham. It was Anguina trtiici that lived in the swollen wheat seed. History of important plant nematodes

Nematode Plant Discoverer Year wheat J.T. Needham 1743 Meloidogyne spp. cucumber M.J. Berkeley 1855 Ditylenchus dipsaci fuller’s teasel Julius Kuhn 1857 Heterodera schachtii sugar beet H. Schacht 1859 Globodera rostochiensis potato Julius Kuhn 1881 Father of nematology Nathanial A. Cobb (1859-1932) is an important person for the study of nematodes in terms of discovering various types of nematodes. The invention of methods for the study of nematodes And being the creator of various words for use in nematology Morphology of Plant Nematode - Small size cannot be seen with the naked eye (approximately 250- 1,200 micrometres in length, 15 micrometres in width) except in the cyst stage - The appearance is filiform liked eel shaped worms, except some genus in adult females stage - The body is unsegment and without appendages - Bilateral symmetry - Female cyst and some adult female have many shapes Male

Female

1 3 Sedendtary endoparasites : Appearance 1. Globodera sp. : body spherical, forming cyst 2. Heterodera sp. : body lemon- 2 shaped, forming cyst 3. Meloidogyne sp. : body pear- shape, no cyst 4. Rotylenchulus sp. : body kidney- 4 shaped, no cyst Sedentary endoparasites : Appearance 1. Cyst form (Globodera sp., Heterodera sp.) : dead female But there is still eggs inside 2. Root knot nematode (Meloidgyne sp.) : lays eggs on the buttom outside the body, eggs are covered with gelatin “egg mass” Morphology of plant nematodes

anus stylet annules Lateral line median ovary bulb excretory pore ovary intestine spicule esophagus

vulva Feeding of nematode

- free living : intracorporeal digestion - plant parasite : extracorporeal digestion Free living

Plant parasite Nematode life cycle Inside egg outside egg 2nd juvenile 2nd molting 1st molting 3rd juvenile 1st juvenile 3rd molting

egg 4th juvenile

fertilization adult 4th molting of nematodes by Chitwood (1950) Kingdom Animalia Plylum Nematoda : 2 class 1. Class : phasmid present (phasmid is sensory organs at posterior) 2. Class Adenophorea : phasmid absent

Plant nematode - 95% in Class Secernentea Order - 5% in Class Adenophorea Order Dorylaimida Classification of nematodes based on behavior - classification of nematodes by host - classification of nematodes by feeding habits - classification of nematodes by movement Classification of nematodes by host 1. Phytophages : plant 2. Microbivore : bacteria 3. Fungivore : fungi 4. Omnivore : vertebrates, invertebrates 5. Predators : other nematode 6. Animal parasite : vertebrates, invertebrates 7. Saprophyte Classification of nematodes by feeding habits 1. Ectoparasitic nematode 2. Endoparasitic nematode 3. Semi-endoparasitic nematode Classification of nematodes by movement 1. Migratory parasitic nematode 2. Sedentary parasitic nematode Ditylenchus Hoplolaimus

Helicotylenchus

Criconemella

Ectoparasitic nematode Helicotylenchus spp. (Spiral nematode) Hoplolaimus spp. (Lance nematode) Criconemella spp. (Ring nematode) Maize

Xiphinema spp. (Dagger nematode) Endoparasitic nematode

Rotylenchulus Meloidogyne

Heterodera Female

Male

Meloidogyne spp. (Root knot nematode) Female

Egg mass

Meloidogyne spp. (Root knot nematode) Rotylenchulus reniformis (Reniform nematode) Heterodera zeae (Cyst Nematode)

Maize Soybean

cyst

Heterodera glycines (Cyst Nematode) Potato cyst

Globodera rostochiensis (Gloden nematode) Classification of nematodes by feeding habits movement and position - Below ground migratory ectoparasites : Helicotylenchus spp., Hoplolaimus spp., Criconemella spp., Xiphinema spp., Longidorus spp., Trichodorus spp., Paratylenchus spp. - Below ground migratory endoparasites : Pratylenchus spp., Radopholus spp. - Below ground sedmentary semi-endoparasites and endoparasites : Rotylenchulus spp., Tylenchulus spp., Heterodera spp., Globodera spp., Meloidogyne sp., Nacobbus spp. - Above ground endoparasites : Anguina spp., Ditylenchus spp., Aphelenchoides sp. Pratylenchus penetrans

Heterodera spp. Meloidogyne spp.

Trichodorus christici Hemicycliophora arenaria Nematode parasitism 1. Direct - wound - lack water and mineral - change plant physiology 2. Indirect - open the way for other microorganisms - nematode vectors of plant viruses Mechanical for plant cell damage 1. Removal of cell contents 2. Cell lysis 3. Iduction of specialized feeding cells 4. Systemic effects

Mechanisms for host disturbance by nematodes 1.1. No visible destructive effect

Migratory ectoparasites (short stylet) : Root hair - Tylenchorhynchus spp. - Paratylenchus spp. 1.2. Immediate removal of cell contents

Migratory ectoparasites : Epidermis - Aphelenchoides spp. 1.3. Delayed removal of cell contents

Migratory and sedentary ectoparasites. : Cortex & Endodermis - Helicotylenchus spp. - Trichodorus spp. - Paratrichodorus spp. -Hemicycliophora spp. - Belonolaimus spp. - Ditylenchus myceliophagus 2.1. Progressive penetration

Migratory endoparasites : Cortex - Pratylenchus spp. - Radopholus spp. 2.2. Cell lysis

: Root tip & Meristem - Ditylenchus spp. 3.1. Nurse cells of Tylenchulus 3.2. Syncytium of Nacobbus 3.3. Syncytium of Heterodera 3.4. Giant cells of Meloidogyne Sedentary parasites : feeding cells

Nurse cell Syncytium Giant cell synergism = เสริมกัน antagonism = หักล้างกัน Interaction of nematodes with other microorganisms 1. Be vector of the other microorganisms. 2. Make physical wound that the way for the other microorganisms. 3. Make the leakage of attractants or nutrients that attract other plant pathogens to infect the plant. 4. When plant cells die, the other microorganisms attack them repeatedly. 5. Change plant physiology/biochemistry then plant is weak. Interaction of nematodes with virus Virus can be transmitted by nematodes must # be seed borne and pollen borne # transmit by mechanical method Types of nematode transmitted viruss 1. NEPO Viruses = Nematode Transmitted Polyhedral Shaped Viruses => # arabis mosaic virus # strawberry latent ring spot virus transmitted by juvenile+adult of Xiphinema sp. & Longidorus sp. 2. NETU Viruses = Nematode Transmitted Tubular Shaped Virus => # tobacco rattle virus # pea early browning virus transmitted by juvenile+adult of Trichodorus sp. Nematode vectors of plant viruses - Viral transmission occurs after the release of enzymes while the nematodes feed nutrients from plants. - virus don’t transmit to the nematode eggs. - No increase the amount of virus in the nematode. - After the molting, the virus will come out of the cuticle or in the small intestine. Plant nematode diseases 1. Root galls or Root knots : Meloidogyne sp. induces root cells to be giant cells by hypertrophy and hyperplasia. 2. Root lesion : Pratylenchus sp. penetrates and migrates inside root tissue.

3. Stubby roots : Trichodorus sp. penetrates meristematic tissue of corn root then root is necrosis and stubby 4. Spring dwarf or Crimp : Aphelenchoides fragariae makes strawberry has many shoots; make lychee stunts; begonia leaf is brown and necrosis. 5. White tip : Aphelenchoides besseyi infects rice leaf tip. 6. Seed gall : ของข้าวสาลีและข้าว ไรย์ เกิดจากไส้เดือนฝอย Anguina tritici infect wheat and rye seeds and live in infected seed for many year. One seed can have 800-32,400 nematodes. 7. Chrysanthemum leaf blight : Aphelenchoides ritzema-bosi is endoparasitic nematode, infect plant through guard cell. Important plant nematode Disease cycle of root-knot nematode Meloidogyne sp.

Life cycle 25 days

Disease cycle of the lesion nematode Pratylenchus sp. Nematodes in root cortex Lesions on peanut pods, Florida. Disease cycle of the stem and bulb nematode Ditylenchus dipsaci

Life cycle 19-25 days Ditylenchus dipsaci (Stem and bulb nematode) Rice Stem nematode

Ditylenchus angustus Disease cycle of the foliar (chrysanthemum) nematode Aphelenchoides ritzema-bosi

Life cycle 2weeks Disease cycle of the stubby-root nematode Trichodorus christii

Life cycle 20 days Nematode damage to corn roots Plant nematode control 1. Cultural control - release flooding - soil solarization - leave the fields fallow - sanitation - crop rotation - applying manure, compost or green manure - using sterile seeds and seedlings - using resistant or tolerant varieties and rootstocks 2. Biological control - using nematode-toxic plants - using natural predators or pathogens of nematodes • antagonistic fungi : Purpureocillium lilacinum (Paecilomyces lilacinus) • antagonistic bacteria : Pasteuria penetrans 3. Chemical control

Fumigants Non-fumigants Methyl bromide Furadan Dazomet Vydate Mocap Rubby Nemacur