UC IPM: UC Management Guidelines for Nematodes on Olive

UC Pest Management Guidelines

Nematodes are true roundworms that are microscopic and must be identified by a nematologist. Root galling is associated with root knot nematodes only.

Root knot or citrus nematodes may be damaging to the root system if relatively high soil populations are present. Trees become slightly weaker, especially in sandy areas, and fruit size on infected trees is reduced.

Management of nematodes with soil fumigation must be done before planting. Proper water and cover crop management can help to avoid damage from these nematodes in established plantings.

Cultural Control
Irrigate infested, weakened trees with greater frequency to avoid plant stress. Most cover crops will host root knot nematode and root lesion nematode.

Common name

Amount /Acre

R.E.I.+

P.H.I.+

(trade name)

(hours)

(days)

1,3–DICHLOROPROPENE*

(Telone II or Telone C35)

Label rates

5 days

N.A.

COMMENTS: Dry the soil by withholding water during summer and using cover crops such as sudangrass or safflower in finer-textured soils. This will usually require one year of field preparation time when following a nematode-infected perennial crop. The drier the soil, the better for deep penetration. Deep-tilling the area can aid the drying process. Surface moisture is required at the field surface before application. Apply no more than 1.5-acre-inches of surface moisture; this can be accomplished by waiting for a fall rain or by sprinkler application. Apply before mid-November. Inject 18-30 inches deep with chisels. Increasing the dose or depth will increase the depth of penetration but 47 gal/acre for Telone C35 and 33.7 gal/acre for Telone II is currently the maximum California rate (i.e., 332 lb a.i./acre). This treatment rate applied broadcast will provide adequate control unless the soil exceeds 12% soil moisture content within the surface 5 feet of depth. In clay loam soils with moisture contents up to 19%, increase the application rate and apply only in 8- to 12-foot-wide planting strips rather than as a broadcast application. Strip applications will only enable 1 year of nematode relief, whereas broadcast applications can provide 6 years of nematode relief. Fumigants such as 1,3-dichloropropene are a source of volatile organic compounds (VOCs) but are minimally reactive with other air contaminants that form ozone. Fumigate only as a last resort when other management strategies have not been successful or are not available.

METAM SODIUM*

(Vapam, Sectagon, etc.)

Label rates

N.A.

. . . or . . .

METAM POTASSIUM*

(K-Pam, etc.)

Label rates

N.A.

COMMENTS: For adequate results, apply sufficient quantities of water to saturate the soil, and be sure all the water applied to the field during treatment has some of the product mixed into it. It is important to add product to the water at a point in the irrigation system where turbulence allows mixing. Apply to soils during springtime when soil moisture is at field capacity but not saturated. After application, wait 14–21 days before planting if soil is coarse to medium in texture, well drained, and warm. When soil is cold (below 60°F), wet, fine textured, or high in organic matter, a waiting period of 30–60 days may be necessary. Water-mediated applications can be effective as deep as the water penetrates into the soil. These treatments will not kill old roots below 3 ft of depth whereas 1,3-D can kill roots at 4-foot depth. In fields where soil is commonly too moist for a 1,3-D application, metam sodium or metam-potassium can be used. In finer textured soils, apply in 6- to 8-acre-inches of water across the field surface. Top label rate is 75 gal/acre for Vapam, Sectagon, etc. and 60 gal/acre for K-Pam. Fumigants such as metam sodium are a source of volatile organic compounds (VOCs) but are minimally reactive with other air contaminants that form ozone. Fumigate only as a last resort when other management strategies have not been successful or are not available.

+	Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
*	Permit required from county agricultural commissioner for purchase or use.
N.A. Not applicable.

UC IPM Pest Management Guidelines: Olive
UC ANR Publication 3452
Nematodes
M. V. McKenry, Kearney Agricultural Center, Parlier

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How to Manage Pests

UC Pest Management Guidelines

Olive

Nematodes

DESCRIPTION OF THE PESTS

DAMAGE

MANAGEMENT

PUBLICATION