Stubby-root nematodes are ectoparasites that live entirely in the soil and feed on root tips.
Damage: They are important pests of potato because they transmit Tobacco rattle virus (TRV), which is the causal agent of corky ringspot disease. Symptoms of corky ringspot include internal brown arcs, rings, or blotches inside the tuber, and arc-shaped lesions on the tuber surface. Stubby-root nematodes rarely damage potatoes without the virus, but they can cause significant stunting of more susceptible plants like onions.
Control: The treatment threshold is upon detection of the nematode when corky ringspot is a concern, but it is often set at 200 or more nematodes per 100 cc soil in fields that are not infested with TRV.
Scientific Name:
Paratrichodorus and Trichodorus species
Type:
Nematodes
Control Options for Stubby Root Nematodes on Potatoes
| Material | Application per Acre | REI | PHI | MOA | Eff. | Notes |
|---|---|---|---|---|---|---|
|
dichloropropene (Telone II) |
20-25 gal | 5 d | - | 11 | E-G | Use 20 gal/A for mineral soil or 25 gal/A for muck. Shank-in at 18-inch depth or more. Soil temperature must be between 40°F and 80°F. |
| Material | Application per Acre | REI | PHI | MOA | Eff. | Notes |
|---|---|---|---|---|---|---|
|
dichloropropene (Telone II) |
20-25 gal | 5 d | - | 11 | E-G | Use 20 gal/A for mineral soil or 25 gal/A for muck. Shank-in at 18-inch depth or more. Soil temperature must be between 40°F and 80°F. |
| Material | Application per Acre | REI | PHI | MOA | Eff. | Notes |
|---|---|---|---|---|---|---|
|
oxamyl (Vydate C-LV) |
2.1-4.25 pt | 48 h | 7 d | 1A | G | Start with an in-furrow application at planting and follow with foliar applications via chemigation. The in-furrow application is optional but is recommended to risk-averse growers and when following alfalfa. Corky ringspot may not be controlled if nematodes are not suppressed prior to tuber initiation. |
| Material | Application per Acre | REI | PHI | MOA | Eff. | Notes |
|---|---|---|---|---|---|---|
|
oxamyl (Vydate C-LV) |
2.1 pt | 48 h | 7 d | 1A | G | Apply the first foliar treatment of 2.1 pints/A via chemigation at crop emergence. Follow with three applications of 2.1 pints/A on 14-day intervals. Stubby root nematodes must be suppressed prior to tuber initiation to control corky ringspot. |