Signs and Symptoms of Damage on Perennials Slides

Nematode Diseases of Perennials Symptoms & Signs Dr. James A. LaMondia Plant Pathologist/Nematologist

The Connecticut Agricultural Experiment Station, Valley Laboratory Windsor, CT

Nematodes Infecting Perennials Meloidogyne hapla - root-knot Aphelenchoides - foliar nematodes Ditylenchus - stem/bulb nematodes Pratylenchus - lesion nematodes

Nematode Diagnostics

30% (99 of 333) samples submitted over 5 years were infected with Meloidogyne hapla

Perennial Ornamentals > 2500 species in >500 genera. Value over $1 billion in US. Propagation by division, seed, and cuttings.

Non-specific Damage Symptoms of poor roots Poor color and vigor Reduce winter hardiness Secondary pathogens/diseases

Nematodes Infecting Perennials Meloidogyne hapla - root-knot Aphelenchoides - foliar nematodes Ditylenchus - stem/bulb nematodes Pratylenchus - lesion nematodes

Nematodes Infecting Perennials Meloidogyne hapla - root-knot Aphelenchoides - foliar nematodes Ditylenchus - stem/bulb nematodes Pratylenchus - lesion nematodes

Nematode Diseases of Tree Fruits

Nematode Damage Reduce tree vigor and yield Reduce winter hardiness Transmit viruses (TmRSV) - apple union necrosis - peach stem pitting Replant Diseases

Nematodes Infecting Tree Fruits Pratylenchus - lesion nematodes Xiphinema - dagger nematodes Criconemella - ring nematodes Meloidogyne hapla - root-knot

Nematode Damage Levels 3 cm

Lesion - 25-150 per 100 soil Ring - 50-200 per 100 cm3 soil 3 Dagger - 1-100 per 100 cm soil (depends on TmRSV)

Apple Replant Trees appear stunted, and growth uneven and slow. Associated with lesion nematodes, soil fungi and bacteria, and poor soil conditions.

Apple or Fruit Replant Disease

Ring Nematode

Apple Union Necrosis

Apple Union Necrosis Problem only on size-controlling rootstocks such as MM106 and scions such as Red Delicious. Shoot growth reduced, heavy set of small fruit, not always lethal.

Tomato RingSpot Virus History

Weed Hosts of TmRSV Common chickweed Lambsquarters White-head aster Oxeye daisy Common thistle Dandelion Wild carrot Swine or Pennycress Leafy/prostrate spurge Red or White clover Common polkweed Buckhorn plantain Common mullein Common plantain Sheep sorrel (red) Curly dock Wild strawberry Broadleaf plantain

Peach Stem Pitting Affected trees appear girdled, lose vigor and eventually die. Trees often yellow early, and set a large number of small fruit. Pits or grooves occur in rootstock.

Cultural Practices • Site preparation • Rotation crops - Brassicas or sorghosudan/sudangrass. • Sod strips - perennial rye or fescue grasses and weed control.

Nematicides • Need determined for each field • Fumigant Nematicides 1,3-dichloropropene metam sodium or dazomet • Non-fumigant Nematicides Fenamiphos or oxamyl

Strawberry Black Root Rot: Plant and Pathogen Interactions James A. LaMondia The Connecticut Agricultural Experiment Station Valley Laboratory Windsor, CT

DISEASE TRIANGLE

DISEASE

Environment

Effect of pathogens on root disease and length %BRR Structural

Feeder

None

10

526

1124

Rf alone

22

491

1440

Rf + Pp

46

411

654

Strawberry Root Types Structural roots – 1° & 2 ° developed cortex. Perennial roots – 2 ° tissues root cortex sloughed off. Feeder roots – 1 ° tissues short-lived, quick cycles.

well

Pratylenchus recovery per g root Root type

1997

1998

Perennial

1.2

23.5

Structural

27.8

118.1

136.6

335.0

1.2

8.4

Feeder

Soil

R. fragariae isolation %2mm roots Root type

Spring

Harvest

Perennial

52

78

Structural

3

40

Feeder

12

27

Pp lesion

17

73

Nematode-Fungus Interactions Split Root Experiments pot 1

pot 2

Pp None None None

Rf Pp+Rf Pp Rf

Nematode-Fungus Split Root pot 1

pot 2

%BRR

Pp

Rf

14 b

None

Pp+Rf

26 a

None

Pp

12 b

None

Rf

8 b

Nematode-Fungus Interactions Rf and Pp associated with BRR. Additive pathogen interaction.

Split root – local interaction. Pp no effect on root exudates or Rf growth in amended media.

Nematode-Fungus Interactions Rf resident on strawberry roots.

Secondary growth > Rf infection. Nematode lesions > Rf infection. Pp, 2° growth cause cell death.

Rf infects dead cells  healthy.

Strawberry health Root growth vs. root loss Tolerance to BRR Insect interactions, white grubs and weevils - breeding

Management Research Nonhost / antagonistic crops. Effect of fertilizer/pH on BRR. Fungicides - Root drench/dip trt Biological control: PGPR; cvs.

IPM – nematode bioassay