Insecticide efficacy is a tricky topic for pear psylla and spider mites. Early suppression is necessary, but season-long control is only possible if natural enemies are not disrupted. Therefore, “efficacy” is a combination of pest control and compatibility with natural enemies.
How to get control of psylla that will last? Avoid “disruptive” materials unless pressure is very high. Limit to two per season and prior to bloom.
| Product | Effect on Psylla | Natural Enemies | Recommendation |
| Particle Films | Surround (kaolin)
Celite (diatomaceous earth) |
Adult Repellency – *key product | Safe, but can flare spider mites if more than three sprays after bloom | 50lb/acre 3 times:
1. early as possible, mid-late march 2. popcorn 3. 1000DD (about 14 days after petal fall) |
| Cocoon (kaolin)
Microna (calcium carbonate) |
Less effective than Surround and Celite | Safe, but can flare spider mites if more than three sprays after bloom. Microna flares rust mites. | * don’t use for psylla, doesn’t work as well and is not legal. |
| IPM Insecticides | AzaDirect/Neemix | Nymph suppression | Very Safe | High pressure organic: once per week for 3 weeks when young nymphs are present. Start near bloom (600DD), again early/mid-June (1500DD)
Low pressure organic: same start times with 1 follow up spray |
| Cinnerate | Psylla adult knockdown
Nymph mortality |
Very Safe | Use high rate with 1st and 3rd Surround or Celite sprays to target adults
(see Surround and Celite timings above) |
|
| Esteem | Adult sterilizer | Safe | 2 sprays: 1. Just before Budburst, 2. Popcorn (2 weeks after first spray) | |
| Centaur | Nymph suppression | Safe | Popcorn or 1000 DD (about 14 days after petal fall) | |
| Ultor | Nymph suppression | Safe | 2 sprays: 1. 1000DD (about 14 days after petal fall), 2. 1400DD (about 1 month after petal fall) |
| Disruptive | Malathion | Adult mortality – Good, short residual | Highly disruptive | Do not use unless pressure is very high. Use once at most.
Spray just before budburst. |
| Bexar | All psylla life stages – Good | Disruptive | Do not use unless pressure is high. Limit to one use.
Spray at popcorn. |
|
| Assail | All psylla life stages – Good | Disruptive | Do not use unless pressure is high. If needed, limit to one use.
Spray at popcorn. |
|
| Actara | Psylla Nymphs – Good | Disruptive | Unnecessary | |
| Rimon | Psylla eggs & nymphs – okay | Disruptive | Unnecessary | |
| Warrior (lambda-cy) | Not effective | Highly disruptive | Stop using this, please. |
Other pest IPM plans:
| Codling moth | Gen 1 | Gen 2 | Gen 3 | ||
| Bloom – Mating Disruption | 375 CMDD – Oil | 525 CMDD – Altacor | 1400 CMDD – oil intrepid | 1550 CMDD – Dimilin | Early Aug- Altacor |
| Spider- and Rust Mites: | 1. Lime sulfur at delayed dormant. 2. Follow IPM sprays for psylla and Codling moth. 3. Sample, if mites approach injury level use Nealta or Envidor, (Cinnerate, TetraCURB, or other essential oil based product if organic) |
Contact
Louis Nottingham
Assistant Professor, Entomology
Washington State University
Tree Fruit Research & Extension Center
1100 N Western Ave., Wenatchee, WA 98801
540-798-2044 (cell)
