IPM Methods: Pest Monitoring Timeline
Timeline of insect degree days/calendar date/plant phenology for key life stages of orchard insects. Dates are estimated for northern Utah, western Colorado, and Idaho; and degree days are provided for a lower temperature threshold of 50, unless otherwise noted.
| Insect or Mite | Life stage | Event/Activity | Degree Days, Date, or Phenology Range |
|---|---|---|---|
| Box Elder Bug | adult | adults find hosts | April |
| adult | 2nd gen. nymphs full grown | Aug - Sept | |
| adult | most migration before overwintering | Oct | |
| Campylomma Bug | eggs | egg hatch | 1st pink of apple |
| nymphs | time to monitor 1st gen. | mid-April - early June | |
| nymphs | summer gen. nymphs active | June - Sept | |
| adults | adults active | late-may - late Sept | |
| Codling Moth | pre-emergence | hang trap | 100 - 150 |
| adult | moth emergence begins; get biofix | 175 - 290 | |
| degree days post biofix: | |||
| larvae | egg hatch begins | 220 - 250 | |
| adult | 1st flight peak | 325 - 581 | |
| larvae | period of greatest egg hatch | 340 - 640 | |
| larvae | egg hatch ends 1st gen. | 920 | |
| eggs | egg laying begins 2nd gen. | 1000 - 1050 | |
| larvae | egg hatch begins 2nd gen. | 1100 | |
| larvae | max hatch period 2nd gen. | 1320 - 1720 | |
| adult | 2nd flight peak | 1337 - 1977 | |
| larvae | egg hatch ends 2nd gen. | 2100 | |
| larvae | egg hatch begins 3rd gen. | 2160 |
| Insect or Mite | Life stage | Event/Activity | Degree Days, Date, or Phenology Range |
|---|---|---|---|
| European Red Mite (base 51) | eggs | 1st egg hatch | 100 - 168 |
| nymphs | summer egg hatch | 424 - 572 | |
| Flatheaded Appletree Borer | adult | adult flight period | June - Aug |
| Greater Peachtree Borer | pre-emergence | hang trap | 400 |
| adult | moth emergence begins | 575 - 650 | |
| adult | moth flight period | mid June - Oct | |
| Green Apple Aphid | eggs | egg hatch | ¼” green |
| nymphs | start scouting | petal-fall - hardened terminals | |
| nymphs | population builds up | late May - early June | |
| Green Fruitworm | adult | moth emergence begins | early spring |
| larvae | hatching | spring | |
| Green Peach Aphid (base 39) |
nymphs | eggs hatch | pink - full bloom |
| Leaf Blister Mites | adults | adults move to new leaf growth | early spring |
| adults | adults enter bud scales to overwinter | Aug - Sept |
| Insect or Mite | Life stage | Event/Activity | Degree Days, Date, or Phenology Range |
|---|---|---|---|
| Lygus Bug (base 54) |
eggs | egg laying | 252 - 300 |
| nymphs | egg hatch | 371 | |
| adult | summer gen. adults begin | 623 | |
| Obliquebanded Leafroller (base 43) |
pre-emergence | hang trap; get biofix | May |
| larvae | peak egg hatch | 600 - 1000 | |
| adult | 2nd gen. moth emergence begins | 1480 - 1683 | |
| adult | 2nd gen. flight peak | 1784 - 2108 | |
| Peach Twig Borer | pre-emergence | hang trap | 300 - 330 |
| adult | moth emergence begins; get biofix | 400 - 450 | |
| degree days post biofix: | |||
| larvae | 5-28% egg hatch; best time to treat | 300 - 400 | |
| adult | 2nd gen. moth flight begins | 900 - 1080 | |
| larvae | 2nd gen. egg hatch; time to treat | 1200 - 1360 | |
| adult | 3rd gen. flight begins | 1760 | |
| larvae | 3rd gen. egg hatch; time to treat | 2140 - 2340 |
| Insect or Mite | Life stage | Event/Activity | Degree Days, Date, or Phenology Range |
|---|---|---|---|
| Pear Psylla | adult | adults active | 0 - 49 |
| egg | 1st gen. egg laying | 1 - 72 | |
| larvae | 1st gen. egg hatch | 60 - 166 | |
| adult | 1st hardshell stage observed | 312 | |
| larvae | 2nd gen. egg hatch | 584 - 750 | |
| Pear Sawfly | eggs | look in terminals | April |
| adults/eggs | adults emerge/ lay eggs | early June | |
| larvae | larvae feed | June | |
| adults | 2nd gen. adults emerge | late July - Aug | |
| Prionus Root Borer | adults | adult emergence | July |
| adults | active in summer months | summer | |
| Root Weevil (base 40) |
pupae | pupal development begins | 564 |
| adult | adult emergence begins | 1056 | |
| eggs | 1st egg laying | 1498 | |
| adult | first leaf feeding observed; apply treatment | early summer | |
| larvae | treat overwintering larvae | late summer - early fall |
| Insect or Mite | Life stage | Event/Activity | Degree Days, Date, or Phenology Range |
|---|---|---|---|
| Rosy Apple Aphid | nymphs | overwintering eggs start hatching | 56 |
| adults | wingless adults active | early bloom - late June | |
| adults | migrate to weed hosts | late June - early July | |
| eggs | adult female lays eggs for overwintering | late summer - early fall | |
| Rust Mite | adults | adults active (decline in hot weather) | 1st bloom - early fall |
| San Jose Scale | pre-emergence | hang trap | 120 - 150 |
| adult | adult male emergence begins; get biofix | 177 - 322 | |
| degree days post biofix: | |||
| crawlers | crawlers begin hatching | 300 - 413 | |
| crawlers | treat crawlers | 600 - 700 | |
| adult | 2nd gen. flight peak | 1426 - 1776 | |
| crawlers | 2nd gen. crawlers emerge | 1916 - 2104 | |
| Spider Mite (McDaniel’s, Two-spotted) | adult | rapid reproduction in high heat | mid to late summer |
| Stink Bugs | adult | adult emergence period | May - June |
| Insect or Mite | Life stage | Event/Activity | Degree Days, Date, or Phenology Range |
|---|---|---|---|
| Walnut Husk Fly (base 41) |
adult | adult emergence begins | 1890 |
| eggs | egg-laying begins | 2480 | |
| larvae | egg hatch begins | 2700 | |
| Western Cherry Fruit Fly (base 41) |
pre-emergence | hang trap | 750 - 800 |
| adult | adult emergence begins; watch trap | 900 - 950 | |
| adult | treat when fruit develops first salmon blush | fruit color salmon blush | |
| adult | 3% of flies emerged | 1060 | |
| adult | last adult catch | 3049 | |
| Western Tentiform Leafminer | adult | adult emergence begins | early spring |
| eggs | egg-laying begins | pink | |
| eggs | egg-laying peaks | bloom | |
| larvae | first mines observed | early - mid May | |
| adult | 1st summer gen., followed by 2 more overlapping generations | early June - late summer | |
| White Apple Leafhopper | nymphs | egg hatch | first pink |
| adult | 2nd gen. egg hatch | late July - early Aug | |
| Woolly Apple Aphid | nymphs & adults | first observation above ground | June - July |
| nymphs & adults | first treatment if population was high last year | early - mid Jul |