Description of the Pest
The mountain leafhopper is a slender, dark brown leafhopper with red eyes and a yellow band behind the head, and a yellow spot in the center of each wing. The leafhopper overwinters on herbaceous vegetation like alfalfa, clovers, and weedy sugarbeet fields. When fields are harvested in spring, the leafhopper disperses to adjacent orchards and can be widely distributed throughout an orchard within a few days. A second peak of leafhoppers may be seen in late July. This leafhopper does not prefer cherry trees, but breeds on weeds (curly dock, California burclover, sweetclovers) on the orchard floor.
Damage
This leafhopper is a concern because it vectors the pathogen that causes X-DISEASE (aka cherry buckskin). It acquires the disease agents by feeding on diseased cherry trees or infected weeds such as clover. It then may infect healthy cherry trees.
Management
Treat immediately after harvest and at 4- to 6-week intervals thereafter. Length of interval depends on residual effectiveness of material used. Remove buckskin-diseased trees immediately after treatment so that the leafhoppers are destroyed before trees are removed.
| 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. | |||||
| POSTHARVEST | |||||
| A. | ESFENVALERATE* | ||||
| (Asana XL) | 4.8–14.5 oz | 2–5.8 fl oz | 12 | 14 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | |||||
| COMMENTS: Provides long-term control. May cause serious outbreaks of spider mites. Do not exceed 0.375 lb a.i./acre per season. At 10 oz/acre has a 4-week residual; at 14 oz/acre has a 6-week residual. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | |||||
| B. | LAMBDA-CYHALOTHRIN* | ||||
| (Warrior II with Zeon) | 1.28–2.56 fl oz/acre | 24 | 14 | ||
| MODE-OF-ACTION GROUP NUMBER1: 3A | |||||
| COMMENTS: Toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | |||||
| C. | THIAMETHOXAM | ||||
| (Actara) | 2–2.75 oz/acre | 12 | 14 | ||
| MODE-OF-ACTION GROUP NUMBER1: 4A | |||||
| COMMENTS: May only be applied once after bloom. Do not apply by air. Has a 4-week residual at the highest label rate. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. Review and follow the California neonicotinoid regulations effective January 1, 2024. Permissible application rates of this insecticide may be lower than label rates if applying more than one neonicotinoid active ingredient or using more than one application method in the same season. |
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| D. | DIAZINON* | ||||
| (Diazinon 50W) | 1 lb/100 gal water | 96 (4 days) | 21 | ||
| MODE-OF-ACTION GROUP NUMBER1: 1B | |||||
| COMMENTS: Provides only immediate control. No control 2 days after application. Avoid drift and tailwater runoff into surface waters. Where cherries are grown adjacent to waterways, do not use this material. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | |||||
| ** | For concentrate applications, use the amount given in 80–100 gal water/acre, or lower if the label allows; for dilute applications, amount is per 100 gal water to be applied in 300–400 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. |
| 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). |