Description of the Pest
Italian pear scale covering is circular, shiny light gray, and has a brown exuvia slightly off center. The body under the scale covering is dark reddish purple. The scale is often found under moss and lichen on old plum trees; it is usually not a problem.
Damage
This scale inflicts its sucking damage on the wood of the tree resulting in reduced tree vigor.
Management
Light populations of Italian pear scale do not harm trees; damaging infestations are rare in California.
Organically Acceptable Methods
Bordeaux treatments, oil sprays, or oil and lime sprays used during the dormant season on organically certified produce.
Treatment Decisions
Insecticide and oil sprays often have little effect on this scale because a large number of them overwinter in the adult stage and are concealed in the tree's moss and lichens. If treatment is necessary, treat during the dormant and delayed dormant period for most effective control. Registered copper and lime sulfur sprays directed at moss and lichens on the tree bark will aid in control of this scale.
| Common name | Amount to use** | REI‡ | ||
|---|---|---|---|---|
| (Example trade name) | (conc.) | (dilute) | (hours) | |
| Not all registered pesticides are listed. 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. Always read the label of the product being used. | ||||
| A. | BORDEAUX# | |||
| 10-10-100 or | Label rates | 24 | ||
| FIXED COPPER# | ||||
| MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M1) | ||||
| COMMENTS: These materials control the growth of lichens, which provide protection to the scale. The removal of the lichens will aid in the control of the scale. This is a slow procedure requiring 1 or more years to be effective. Although the lichens are killed quickly, considerable weathering must occur before they are removed. Thorough coverage including trunks and limbs is essential. Not all copper compounds are approved for use in organic production; be sure to check individual products. For information on making Bordeaux mixtures, see UC IPM Pest Note: Bordeaux Mixture, ANR Publication 7481. | ||||
| B. | DORMANT OIL such as: | |||
| DORMANT FLOWABLE EMULSION | 6 gal | 1.5 gal | 4 | |
| NARROW RANGE OIL# | 4 gal | 1 gal | 4 | |
| MODE OF ACTION GROUP NAME (NUMBER1): A contact fungicide with smothering and barrier effects. | ||||
| COMMENTS: Oil used alone will only provide partial control. Oil applications at this time may cause some young shoots to burn or dieback, especially in years when trees are water-stressed, or have recently been subjected to freezing temperatures or to dry winds. Dormant flowable emulsion is less likely to cause burn. Some varieties, especially those that are weak growers or low in vigor because of soil or other location-related issues, can be especially sensitive to oil. Not all oil products are organically acceptable; be sure to check individual products. | ||||
| ** | For dilute applications, rate is per 100 gal water to be applied in 300–500 gal water/acre, according to label; for concentrate applications, use 80–100 gal water/acre, or lower if the label allows. |
| # | Acceptable for use on organically grown produce. |
| 1 | Rotate insecticides 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; insecticides with a 1B group number should be alternated with insecticides that have a group number other than 1B. Mode-of-action group numbers for insecticides and miticides (un=unknown or uncertain mode of action) are assigned by IRAC (Insecticide Resistance Action Committee). |