How to Manage Pests

UC Pest Management Guidelines

Olive

Oleander Scale

Scientific Name: Aspidiotus nerii

(Reviewed 3/14, updated 3/14)

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. Control ants in the orchard because they disrupt biological control (for more information, see ANTS).

Biological Control

Several species of Aphytis, including A. melinus, are important parasites of oleander scale. Where insecticides such as carbamates (IRAC Group 1A), organophosphates (1B), and pyrethroids (3) are used, biological control will be disrupted. Be sure to monitor scale populations if disruptive insecticides are used.

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.‡
(example trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
 
POSTBLOOM (LATE MAY THROUGH JUNE WHEN CRAWLERS ARE PRESENT)
 
A. NARROW RANGE OIL#
  (Organic JMS Stylet Oil, etc.) 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. PYRIPROXYFEN
  (Esteem 0.86EC) 13–16 fl oz 12 7
  MODE-OF-ACTION GROUP NUMBER1: 7C
  COMMENTS: Insect growth regulator. Has no activity on adult stage but hatching of eggs laid by treated adults will be suppressed. Most effective when applied against the crawler stage. Use higher rate for high scale numbers.
 
C. 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 SL) 5.0–7.5 qt 12 14
  MODE-OF-ACTION GROUP NUMBER1: 1A
  COMMENTS: Do not exceed 2 applications per year. This material is very destructive to most natural enemies. To protect bees, apply only during late evening, night, or early morning when bees are not present. 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#
  (Organic JMS Stylet Oil, etc.) 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. PYRIPROXYFEN
  (Esteem 0.86EC) 13–16 fl oz 12 7
  MODE-OF-ACTION GROUP NUMBER1: 7C
  COMMENTS: Insect growth regulator. Has no activity on adult stage but hatching of eggs laid by treated adults will be suppressed. Most effective when applied against the crawler stage. Use higher rate for high scale numbers.
 
C. 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 SL) 5.0–7.5 qt 12 14
  MODE-OF-ACTION GROUP NUMBER1: 1A
  COMMENTS: Do not exceed 2 applications per year. This material is very destructive to most natural enemies. To protect bees, apply only during late evening, night, or early morning when bees are not present. 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#
  (Organic JMS Stylet Oil, etc.) 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 per 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. To protect bees, apply only during late evening, night, or early morning when bees are not present.
 
** 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 R.E.I. exceeds the P.H.I. 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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