Apple

Peak first-generation codling moth entry

Malus domestica

Rosaceae · broadleaf deciduous tree · introduced

Last updated

Data Maturity
Structured Multiple sources. Expert review underway.
Watch for this season
Fire BlightHigh

Bloom Infection Window

Codling mothModerate

Pupation

Apples in the Puget Sound lowlands demand more management than most home gardeners expect. Scab thrives in wet springs and is the primary fungal threat; codling moth and apple maggot are the two key insect pests. Codling moth attacks early (May-June first generation, July-August second generation) and bores to the core. Apple maggot is single-generation, peaking July-August with meandering flesh tunneling. Without some form of spray program or physical barriers (bagging, trunk banding), expect damaged fruit most years. Cultivar choice is the first defense: modern disease-resistant varieties (Liberty, Enterprise, Pristine) significantly reduce scab pressure and spray needs. Dwarf rootstocks (M.9, M.26) keep trees manageable for spraying, pruning, and netting. Site in full sun with good air circulation to minimize powdery mildew and reduce overwintering pest populations. Most varieties need a pollinizer; check bloom-time compatibility. Late-maturing cultivars (Fuji, Granny Smith) avoid some early pest pressure. Most lowland soils are adequate if drainage is acceptable; on alluvial clay or over shallow hardpan, raised beds improve results. Summer drought stress opens the door to secondary pests and disease. If you are not willing to spray at all, consider heirloom or cider varieties that tolerate cosmetic damage, or choose dwarf, bagged trees for spotless fruit.

— Chris Welch, ISA Certified Arborist

Malus domestica (Rosaceae) is a deciduous fruit tree originating in Central Asia (primarily Kazakhstan and adjacent regions). It grows 15 to 30 feet tall and wide depending on rootstock, forming a rounded to spreading crown. Pink-white flowers (1 to 1.5 inches across) appear in cymes of 4 to 6, with the central "king bloom" opening first. Thousands of cultivars exist, spanning a vast range of fruit size, color, flavor, and ripening season.

Apple requires full sun to part shade on moist, well-drained soil (pH 6.0 to 8.0). Most cultivars are not self-fertile and require a compatible pollination partner blooming at the same time. Maintenance is high: the species is subject to extensive disease pressure (scab, fire blight, powdery mildew, cedar-apple rust among others) and insect damage (codling moth, apple maggot, aphids). Dwarfing rootstocks control tree size and often improve precocity. Hardy in Zones 4a to 9b.

Field Observations

Malus domestica - fruit initial development
Field Observation
Malus domestica · Apple
fruit initial development
May 11, 2026 · Issaquah · 2,035 GDD₃₂ · BBCH 71
Malus domestica - flower
Field Observation
Malus domestica · Apple
flower
April 23, 2026 · Issaquah · 1,596 GDD₃₂ · BBCH 61
Malus ×domestica 'Jonagold' - bud swell
Field Observation
Malus ×domestica 'Jonagold' · Apple
bud swell
March 22, 2026 · Kent · 930 GDD₃₂ · BBCH 51

Quick Facts

Height
15-30 ft (highly variable by rootstock: M9 ~8 ft, M26 ~12 ft, M7 ~18 ft, MM111 ~25 ft, seedling ~30 ft)
Spread
15-30 ft (parallels mature height; varies by rootstock and pruning system)
Growth Rate
Medium
Light
Sun to Part Shade
Soil
Moist, Well Drained
Water
Low to moderate
Hardiness
Zone Zones 4a–9b
Bloom Time
Mid- to late April in Puget Sound; commercial cultivars span early/mid/late bloom (~10 day spread); WSU bloom-timing charts distinguish cultivar groups for pollinizer planning
Fall Color
Null
Origin
Central Asia (Tian Shan mountain range

Phenological Calendar

As of May 11, 2026, Puget Sound stations range from 1851.2 to 2039.5 GDD₃₂. Apple has reached peak first-generation codling moth entry (1800 GDD₃₂) and is approaching fruit diameter increase / late development, predicted around May 22.

Regional Season Tracker

GDD₃₂ accumulation across 7 Puget Sound stations · as of May 11, 2026
Station GDD₃₂ Current Stage Next To Go
Issaquah / East King 2,040 Peak first-generation codling moth entry Fruit diameter increase / Late development 241
Kent / Auburn 2,030 Peak first-generation codling moth entry Fruit diameter increase / Late development 250
Seattle / UW 2,006 Peak first-generation codling moth entry Fruit diameter increase / Late development 274
Olympia / Tumwater 1,968 Peak first-generation codling moth entry Fruit diameter increase / Late development 312
Tacoma / Puyallup 1,935 Peak first-generation codling moth entry Fruit diameter increase / Late development 345
Bellingham / Whatcom 1,917 Peak first-generation codling moth entry Fruit diameter increase / Late development 363
Sequim / Rain Shadow 1,851 Peak first-generation codling moth entry Fruit diameter increase / Late development 429
Stage GDD32 Typical Window
Dormancy break / Bud swell BBCH 01 — Late February to mid-March (Kent, WA)
Green tip BBCH 03 375 Mid-March (Kent, WA)
Tight cluster BBCH 05 548 Late March to early April (Kent, WA)
Pink bud BBCH 57 730 Mid-April (Kent, WA)
Bloom start / First bloom BBCH 61 — —
Full bloom BBCH 65 754 Mid-April (Kent, WA)
Petal fall BBCH 67-69 841 Late April (Kent, WA)
Fruit set / Young fruit development BBCH 71-75 1160 Mid to late May (Kent, WA)
Fruit bagging window BBCH 75-79 1125 Late May through early June (Kent, WA)
● Peak first-generation codling moth entry BBCH 79-81 NOW 1800 June through early July (Kent, WA)
○ Fruit diameter increase / Late development BBCH 81-87 NEXT 2280 Late June through July (Kent, WA) est. May 22 (forecast)
Maturity / Pre-harvest BBCH 87-89 3400 August through October depending on cultivar (Kent, WA) est. Jul 2 (avg)
blooming BBCH 61 — —

Sources: PNW Insect Management Handbook ; WSU Tree Fruit Extension (codling moth indicator) ; field observation, Issaquah WA 2026-05-11 (GDD₃₂ estimated from May 10: 2009.6 + ~25/day trend) ; Codling Moth Phenology Model (656 GDD50 peak larval entry) ; USDA phenology models About GDD₃₂ →

Season tracker for Kent / Auburn as of May 11, 2026. Predicted dates use 16-day weather forecast through May 27, 2026, then climate normals.

Diseases — Regionally Documented (2)

Pests — Regionally Documented (2)

Cultivars (6)

'Gravenstein'
Early, large fruit. Distinctive irregular round shape with ribbing. Yellow with red stripes. Aromatic, balanced sweet-tart flavor. Excellent for cider and fresh eating. Vigorous tree, somewhat spreading habit.
Performs well in Puget Sound lowlands. Prefers full sun. Requires adequate space; vigorous growth habit. Biennial bearing tendency in commercial orchards; thinning helps reduce alternate bearing in home orchards.
'Liberty'
Medium to large fruit. Red color on yellow-green ground. Crisp, juicy, moderately tart flavor. Disease-resistant pedigree: parentage includes resistant genes from Malus floribunda and other sources. Tree is semi-dwarf.
Excellent choice for home orchards in the Puget Sound region where scab is chronic. Requires less spraying than traditional cultivars. Semi-dwarf rootstock keeps trees manageable. Good for espalier or intensive planting.
'Enterprise'
Large fruit. Dark red color. Crisp, tart flavor with excellent storage capability. Resistant parentage from Malus floribunda. Tree moderate vigor, somewhat upright habit.
Good for the Puget Sound lowlands where scab pressure is high. Fruit stores exceptionally well (4-6 months cold storage). Adequate chill hour availability (800-1,000 hours available in PNW lowlands, 700 required).
'Fuji'
Large to very large fruit. Red-striped on yellow ground. Very crisp, sweet flavor with slow browning (high sugar content preserves color when cut). Excellent fresh eating and storage. Vigorous, somewhat spreading tree habit.
Popular in home orchards but requires more disease management in Puget Sound lowlands than modern resistant varieties. Excellent for fresh eating and long-term storage. Tree's vigor can create management challenges in small spaces. Biennial bearing tendency common without thinning.
'Chehalis'
Medium to large golden-yellow fruit. Mild, sweet flavor. Somewhat similar to 'Golden Delicious' but better adapted to Puget Sound conditions. Moderate vigor tree with spreading habit. Bred in Washington State.
WSU-bred variety selected for Puget Sound performance. Scab resistance makes it a strong choice for low-input orchards in western WA. Adequate chill hours available in PNW lowlands. Good pollinator compatibility with 'Jonagold' and 'Liberty'.
'Red Jonagold'
Red sport of 'Jonagold'. Large fruit with heavily red-blushed skin over yellow-green ground. Crisp, sweet-tart flavor with characteristic aromatic quality. Vigorous tree, partially self-fertile but produces better with pollinizer.
More widely red coloring than standard 'Jonagold'; color advantage over parent. Requires disease management program in Puget Sound lowlands due to scab susceptibility. Partially triploid — produces limited viable pollen; 'Chehalis', 'Liberty', or 'Fuji' as pollinators recommended.