Description of the Pest
European red mites overwinter as eggs located at the base of buds and spurs on smaller branches or in wounds. Eggs are red with a slender stipe arising from the center. Newly hatched mites are green, but with feeding turn red with a white spot at the base of each hair. These mites have 5 to 10 generations per year.
Damage
European red mites cause leaf stippling. Prolonged feeding causes leaves to pale and appear bronzed and burned at the tips and margins. Leaf drop can occur at high infestation levels (in excess of 100 mites per leaf for extended periods). At low levels, this mite can be beneficial; it serves as an alternative food for predators.
Management
Predators will generally keep European red mite numbers at low levels. Allowing low numbers of European red mites in the orchard during spring enables predator numbers to increase to levels that are more effective in controlling webspinning mites. Hot weather and predators cause European red mite numbers to decline in summer.
Biological Control
Several predaceous species feed on European red mite, including lacewings (Chrysoperla spp., Chrysopa spp., and Hemerobius sp.), damsel bugs (Nabis sp.), lady beetles (Stethorus picipes), and minute pirate bug (Orius tristicolor). Western predatory mites, Galendromus (= Metaseiulus) occidentalis, also feed on European red mite but are less effective predators of European red mite than webspinning mites because of their inability to break through the egg shell of the European red mite.
Organically Acceptable Methods
Use oil sprays that are acceptable for use on organically grown apricots.
Monitoring and Treatment Decisions
Monitor orchards once a week during the growing season when monitoring for other pests. No treatment thresholds have been established, but trees are able to tolerate greater numbers of European red mites than webspinning mites per leaf. A dormant oil spray is the preferred treatment and is intended to control European red mite eggs. However, some apricot cultivars are sensitive to dormant oil sprays.
| Common name | Amount to use** | REI‡ | PHI‡ | ||||||
|---|---|---|---|---|---|---|---|---|---|
| (Example trade name) | (conc.) | (dilute) | (hours) | (days) | |||||
| 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. | |||||||||
| DORMANT | |||||||||
| A. | NARROW RANGE OIL# | 4–8 gal | 1.5–2 gal | 12 | 0 | ||||
| MODE OF ACTION: Contact including smothering and barrier effects. | |||||||||
| COMMENTS: Cover all parts of the tree. Oil alone will control low to moderate infestations. Do not use oil sprays on water-stressed trees. Some of the new lower-chilling varieties, especially Poppycot, can be highly susceptible to oil damage. Use extreme care when applying oil to these varieties. Check with certifier to determine which products are organically acceptable. | |||||||||
| SPRING | |||||||||
| A. | BIFENAZATE | ||||||||
| (Acramite 50WS) | 0.75–1 lb | 0.1875–0.25 lb | 12 | 3 | |||||
| MODE-OF-ACTION GROUP NUMBER1: un | |||||||||
| COMMENTS: Relatively safe for beneficial predaceous mites. Apply with ground equipment. Requires complete coverage of both leaf surfaces for effective control. | |||||||||
| B. | SPIRODICLOFEN | ||||||||
| (Envidor 2SC) | 16–18 fl oz | 4–4.5 fl oz | 12 | 7 | |||||
| MODE-OF-ACTION GROUP NUMBER1: 23 | |||||||||
| COMMENTS: Apply with ground equipment; need complete coverage of both leaf surfaces for good control. | |||||||||
| C. | ABAMECTIN* | ||||||||
| (Agri-Mek 0.15 EC) | 10–20 fl oz | 2.5–5 fl oz | 12 | 21 | |||||
| MODE-OF-ACTION GROUP NUMBER1: 6 | |||||||||
| COMMENTS: May be combined with oil. Do not make more than two applications per growing season and allow at least 21 days between applications. Do not exceed 20 fl oz/acre per application. | |||||||||
| D. | NARROW RANGE OIL# | 4–8 gal | 1.5–2 gal | 12 | 0 | ||||
| MODE OF ACTION: Contact including smothering and barrier effects. | |||||||||
| COMMENTS: Be sure that trees are well watered before sprayinging. Check with certifier to determine which products are organically acceptable. | |||||||||
| E. | CLOFENTEZINE | ||||||||
| (Apollo SC) | 2–8 oz | 0.5–1 oz | 12 | 21 | |||||
| MODE-OF-ACTION GROUP NUMBER1: 10A | |||||||||
| COMMENTS: This material is more effective in the early part of the year; apply after sampling indicates pest mites are increasing but before significant damage or webbing is present. Kills eggs and young larval stages. Good coverage is required; use a minimum of 50 gal water/acre for concentrate and a maximum of 400 gal water/acre for dilute. To delay development of resistance, use only once per season. | |||||||||
| F. | HEXYTHIAZOX | ||||||||
| (Onager) | 12–24 oz | 3–6 oz | 12 | 7 | |||||
| (Savey 50DF) | 3–6 oz | 0.75–1.5 oz | 12 | 28 | |||||
| MODE-OF-ACTION GROUP NUMBER1: 10A | |||||||||
| COMMENTS: Apply after bloom but before adult mite numbers increase. Controls eggs and immatures that are sprayed or move onto treated surfaces; does not kill adult mites but will kill eggs laid on sprayed surfaces. Do not make more than one application per year. | |||||||||
| ** | For concentrate applications, use the amount given in 80 to 100 gal water/acre or lower if the label allows; for dilute application, amount is per 100 gal water to be applied in 300 to 400 gal water/acre, according to label. |
| ‡ | Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) 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 produce. |
| 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 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). |