Pear at First Bloom
See General Recommendations for guidelines on table use. Read all product labels carefully.
Avoid killing bees on blooming cover crops. See Hazards to Bees.
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Fire blight: There is a risk of fire blight infection any time there are flowers on the tree, the weather is warm, and wetting occurs. Watch the model.
Delayed dormant (2 to 4 weeks before bloom): Apply fixed copper bactericides for orchard sanitation. This reduces the primary inoculum and delays the pathogen’s colonization of the flowers. A delayed dormant application of a fixed copper is recommended only if fire blight was present in the orchard last season.
Early bloom. Apply biologicals (Blossom Protect) during early bloom two times. The second application should be after lime sulfur when it is applied. In smooth skinned pears in wetter areas russet risk may be unacceptably high. Bloomtime Biological is a fruit safe alternative material.
Full bloom to petal fall. Watch the model. If an infection event occurs, apply an antibiotic as soon as possible, but within 24 hours of infection (usually wetting of flowers). Repeated antibiotic sprays may be necessary during extended high or extreme risk periods. Best results are obtained when applied within 24-hour window before flower wetting during a high infection risk period. Beneficial only for flower infection prevention. Product used must contact the interior of the flowers in sufficient water and approved wetting agent to completely wet the interior. One pound of any 17% oxytetracycline product per 100 gallons gives a 200 ppm solution. Kasugamycin is another effective antibiotic. Some trials have shown that a full rate of Kasumin and a half rate of oxytetracycline provides excellent control. Applications of less than 100 gal/A can be effective on small trees if flower interiors are well covered, but do not drop the ppm below 200 (oxytetracycline). Application by ground equipment on each row is highly recommended. Application of antibiotics by aircraft is not recommended. Many fire blight bacteria in the Pacific Northwest are resistant to streptomycin, another registered antibiotic.
Organic. Prebloom. Fixed copper sanitation if fire blight was in the orchard last year. One to two applications of biologicals (Blossom Protect). Reapply if lime sulfur which is antimicrobial is used. Depending on the cultivar russet risk and the CougarBlight model risk follow with Bacillus subtilis (Serenade Optimum) (most fruit safe) every 2-5 days during flower/petal fall or copper hydroxide/octanoate (Cueva/Previsto) every 5 to 6 days (This option is less fruit safe for russet and risk may be too high for high smooth skinned pears).
Bacillus thuringiensis subsp. kurstaki: Bts are stomach poisons, so complete coverage is very important for control. Two or three applications are usually required. Apply when forecasts predict a warm weather pattern for 3 or more days. This timing is too early for control of obliquebanded leafroller.
CM pheromone dispensers: Many pear growers in Washington use pheromones to help control codling moth. Pheromone dispensers must be in place before the first moth flight, that is prior to bloom. The number of dispenser units per acre will depend on the product used and pest pressure.
Hand-applied dispensers should be placed within the top 2 feet of the tree canopy. It is strongly recommended that full label rate of any hand-applied pheromone dispenser be used. Reducing the rate of hand-applied dispensers per acre can reduce efficacy and result in more damage from codling moth or require the use of more insecticides to achieve acceptable control.
Some pear growers are using aerosol pheromone emitters (CheckMate CM-O Puffer and Isomate CM MIST) to control codling moth. This technology is used at a rate of one pheromone emitter per acre. WSU research has shown that the aerosol emitter technology works as good as a full rate (400 dispensers per acre) of a hand-applied dispenser technology. However, the borders of orchards need to be treated with hand-applied pheromone dispensers to cover gaps resulting from the number of aerosol emitters that are applied per acre.
Actigard 50WG: For bloom applications: Apply 1 - 2 oz/A in a tank mix with a fire blight treatment (generally an antibiotic) that is standard in your area. This is generally 2-3 applications between 20% bloom and petal fall depending on the environmental conditions. Do not apply closer than a 7 day interval.
After removing cankers: Mix 1 oz Actigard in 1 quart of 1% penetrant. Apply to the branch area immediately below the canker after cutting 12-18 inches below the canker. In small trees the application can be made to the central leader below the branch where fire blight was cut.
oxytetracycline: Apply within 24 hours before or after a blight infection event. Use oxytetracycline in ground application as a concentrate spray, 1 pound per 100 gallons per acre, which gives a 200 ppm solution. Acidify alkaline spray water to below pH7.