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UC Pest Management Guidelines


Oleander scales on ivy.

Olive

Oleander Scale

Scientific Name: Aspidiotus nerii

(Reviewed 1/08, updated 1/09)

In this Guideline:


DESCRIPTION OF THE PEST

The adult female oleander scale is an armored scale that is about 0.1 inch (2.5 mm) long and oval. It has a waxy covering that is whiter than olive scale with a yellow or light brown spot near the center. The adult male scale is elongate. If the coverings are removed, the female body is yellow, while the male scale is brownish yellow. This scale is most common on leaves in the lower part of the tree. There are several generations a year.

DAMAGE

The oleander scale infests olive fruit and delays maturity at the spot where it feeds. Thus, damage is seen as prominent green spots on purple fruit, in direct contrast to the dark spots caused by olive scale. Heavy infestations seriously deform fruit, and fruit spotting renders the olive worthless. Extremely heavy infestations reduce oil content by as much as 25%. Leaf and twig damage also result in lost production.

MANAGEMENT

Oleander scale can be effectively controlled by natural enemies and does not usually cause economic damage. Preserve these natural enemies by selecting insecticides for other pests that do not kill beneficial insects. Chemical treatment is rarely needed for oleander scale unless biological control is disrupted by treatments applied for other pests.

Biological Control
Several species of Aphytis, including A. melinus, are important parasites of oleander scale.

Organically Acceptable Methods
Biological control and certain oil sprays are acceptable methods in an organically certified crop.

Treatment Decisions
If treatments are necessary, treat the first brood in late May and June or the second brood in late July and August. Apply the first brood treatment when young scales are observed moving onto fruit. Treating scales in early July, between broods, is not recommended. Although efficacy data are not available, postharvest treatments should also be effective.

Common name Amount to Use** R.E.I.+ P.H.I.+
(trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
When choosing a pesticide, consider information relating to the impact on natural enemies and honey bees and environmental impact. Not all registered pesticides are listed. Always read label of product being used.
 
POSTBLOOM (Late May through June when crawlers are present)
A. NARROW RANGE OIL# Label rates 4 0
  MODE OF ACTION: Contact including smothering and barrier effects.
  COMMENTS: Effective against light to moderate infestations, especially when used in conjunction with pruning to open the orchard canopy. Most effective when applied against the crawler stage. Spray at night or early morning if temperatures are expected to exceed 90°F during the day. Check with certifier to determine which products are organically acceptable.
 
B. NARROW RANGE OIL 1.5 gal 4 0
  MODE OF ACTION: Contact including smothering and barrier effects.
  COMMENTS: For heavy to severe infestations, add the following insecticide to the oil spray. Spray at night or early morning if temperatures are expected to exceed 90°F during the day.
  . . . PLUS . . .
  CARBARYL*
  (Sevin) 80S 1–1.25 lb 12 14
  MODE OF ACTION GROUP NUMBER1: 1A
  COMMENTS: Do not exceed 2 applications/year. This material is very destructive to most natural enemies. For tank mixes, observe all directions for use on all labels, and employ the most restrictive limits and precautions. Never exceed the maximum a.i. on any label when tank mixing products that contain the same a.i.
 
SUMMER (July 15–August)
A. NARROW RANGE OIL# Label rates 4 0
  MODE OF ACTION: Contact including smothering and barrier effects.
  COMMENTS: Effective against light to moderate infestations, especially when used in conjunction with pruning to open the orchard canopy. Do not apply any oil between August 20 and harvest to olives used for Spanish or green-ripe processing because of the risk of fruit spotting. Most effective when applied against the crawler stage. Spray at night or early morning if temperatures are expected to exceed 90°F during the day. Check with certifier to determine which products are organically acceptable.
 
B. NARROW RANGE OIL 1.5 gal 4 0
  MODE OF ACTION: Contact including smothering and barrier effects.
  COMMENTS: For heavy to severe infestations, add the following insecticide to the oil spray. Do not apply any oil between August 20 and harvest to olives used for Spanish or green-ripe processing due to fruit spotting. Spray at night or early morning if temperatures are expected to exceed 90°F during the day.
  . . . PLUS . . .
  CARBARYL*
  (Sevin) 80S 1–1.25 lb 12 14
  MODE OF ACTION GROUP NUMBER1: 1A
  COMMENTS: Do not exceed 2 applications/year. This material is very destructive to most natural enemies. For tank mixes, observe all directions for use on all labels, and employ the most restrictive limits and precautions. Never exceed the maximum a.i. on any label when tank mixing products that contain the same a.i.
 
POSTHARVEST (October–November)
A. NARROW RANGE OIL# Label rates 4 0
  MODE OF ACTION: Contact including smothering and barrier effects.
  COMMENTS: Effective against light to moderate infestations, especially when used in conjunction with pruning to open the orchard canopy. Most effective when applied against the crawler stage. Spray at night or early morning if temperatures are expected to exceed 90°F during the day. Check with certifier to determine which products are organically acceptable.
 
B. NARROW RANGE OIL 1.5 gal 4 0
  MODE OF ACTION: Contact including smothering and barrier effects.
  COMMENTS: For heavy to severe infestations, add the following insecticide to the oil spray. Spray at night or early morning if temperatures are expected to exceed 90°F during the day.
  . . . PLUS . . .
  METHIDATHION*
  (Supracide) 25WP 2 lb 48 0
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Use with or without oil. Application of methidathion with, or closely following, a fungicide containing lime will negate the insecticide's effectiveness. The application of this material should precede the application of fungicides containing lime. Do not apply more than 12 lb/acre/year. For tank mixes, observe all directions for use on all labels, and employ the most restrictive limits and precautions. Never exceed the maximum a.i. on any label when tank mixing products that contain the same a.i.
 
** Amounts per 100 gal water (except where otherwise stated), using 400-500 gal solution per acre.
+ 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.
# Acceptable for use on organically grown crops.
1 Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Olive
UC ANR Publication 3452
Insects and Mites
F. G. Zalom, Entomology, UC Davis
P. M. Vossen, UC Cooperative Extension, Sonoma County
R. A. Van Steenwyk, Insect Biology, UC Berkeley
M. W. Johnson, Kearney Agricultural Center, Parlier
Acknowledgment for contributions to Insects and Mites:
G. S. Sibbett, UC Cooperative Extension, Tulare County
L. Ferguson, Pomology, UC Davis

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