Plant Clinic

Pest Management Calendar

This calendar provides information about life cycle events for common Missoula County plants, pests, and diseases.

May 2025

This Month

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27	28	29	Apr 30	May 1	2	3
				12:00 am Time to fertilize lawns
				12:00 am Grasshoppers start hatching
				6:00 pm Herbicide Basics Webinar Series (2/4): Aquatic Herbicide Case Studies

4	5	6	7	8	9	10
12:00 am Check for Leafroller larvae on fruit trees			12:00 am Check for aphids on aphid susceptible trees and shrubs
			4:00 pm Pesticide Applicator Spring Training	6:00 pm Herbicide Basics Webinar Series (3/4): Riparian and Terrestrial Herbicides

11	12	13	14	15	16	17
12:00 am Fireblight disease enters "blossom stage"		12:00 am Protect new Apple and Hawthorne leaves from Rust disease			12:00 am Check peach trees for Peach leaf curl
		12:00 am Average week of last frost in Missoula
				6:00 pm Herbicide Basics Webinar Series (4/4): Reducing Unnecessary Herbicides in our Environment

18	19	20	21	22	23	24
12:00 am Check for Fungal Leafspot and Rust disease		12:00 am Treat white leafhopper nymphs		12:00 am Check for Birch Leafminer larvae inside leaves.
				12:00 am Check for Black-knot disease infection in chokecherry and plum trees

25	26	27	28	29	30	May 31
12:00 am Check for Cutworms or Webworms	12:00 am Check for Oyster Shell Scale egg hatch - Treat now		12:00 am Check for Spruce Budworms - Treat Now		12:00 am Treat for adult Western Raspberry Fruitworm
					12:00 am Apply "Nolo Bait" to areas grasshoppers are hatching

Time to fertilize lawns (Day 3 of 3 )

Until 11:00 pm

Check for Leafroller larvae on fruit trees (Day 1 of 3 )

Starts 12:00 am

Check for Leafroller larvae on fruit trees (Day 2 of 3 )

All Day

Check for Leafroller larvae on fruit trees (Day 3 of 3 )

Until 11:00 pm

Check for aphids on aphid susceptible trees and shrubs (Day 2 of 4 )

All Day
Herbicide Basics Webinar Series (3/4): Riparian and Terrestrial Herbicides

6:00 pm - 7:30 pm

Check for aphids on aphid susceptible trees and shrubs (Day 3 of 4 )

All Day

Check for aphids on aphid susceptible trees and shrubs (Day 4 of 4 )

Until 11:00 pm

Fireblight disease enters "blossom stage" (Day 1 of 2 )

Starts 12:00 am

Fireblight disease enters "blossom stage" (Day 2 of 2 )

Until 11:00 pm

Check peach trees for Peach leaf curl (Day 1 of 2 )

Starts 12:00 am

Check peach trees for Peach leaf curl (Day 2 of 2 )

Until 11:00 pm

Check for Fungal Leafspot and Rust disease (Day 1 of 2 )

Starts 12:00 am

Check for Fungal Leafspot and Rust disease (Day 2 of 2 )

Until 11:00 pm

Treat white leafhopper nymphs (Day 1 of 2 )

Starts 12:00 am

Treat white leafhopper nymphs (Day 2 of 2 )

Until 11:00 pm

Check for Cutworms or Webworms

12:00 am - 11:00 pm

Check for Oyster Shell Scale egg hatch - Treat now (Day 1 of 2 )

Starts 12:00 am

Check for Oyster Shell Scale egg hatch - Treat now (Day 2 of 2 )

Until 11:00 pm

Check for Spruce Budworms - Treat Now (Day 1 of 2 )

Starts 12:00 am

Check for Spruce Budworms - Treat Now (Day 2 of 2 )

Until 11:00 pm

Using Integrated Pest Management (IPM) strategies

IPM means getting to know your pests.

When is the pest MOST vulnerable, infective, or invasive?
When is the pest most vulnerable to least-toxic management strategies?
What is the least-toxic management tool that can be used successfully?

IPM optimizes plant health through the following:

Managing garden and landscape soils to promote drainage and aeration
Maximizing soil health by adding organic matter and properly timed fertilizers.
Pruning and irrigating based on the needs of particular plants.
Knowing the plant's level of susceptibility to pest damage.