The Online Gardener's Handbook 2010
Chapter 1: Causes of Plant Injury
Ontario Development Calendar

Table of Contents

  1. Ontario Development Calendar
  2. Legend
  3. Learn More

Ontario Insect Development Calendar

To effectively control insects, it is important to understand the life cycle of the pest that is attacking the plant(s) in your garden. Management strategies are only effective when applied at the correct time and in the most effective way. It makes no sense to apply management strategies when the controllable stage is no longer present.

The following table outlines when various insects are active and when you should watch for their activity. Keep in mind that small numbers of beetles and caterpillars can be removed by hand, and birds and other beneficial insects often reduce harmful insects to acceptable levels.

Defoliators

PestAprilMay JuneJulyAugustSept.Host Plant
Birch Leaf Miners Adult Larva Larva Adult Larva Adult Larva OW Pupa Birch
Cedar Leaf Miners Larva Larva Pupa Adult Egg Adult Egg Larva OW Larva White Cedar
Dogwood Sawflies OW Larva,Pupa Pupa, Adult Egg Adult Egg Larva Larva OW Larva All Dogwood
Eastern Tent Caterpillars OW Egg Mass Larva Larva Adult Adult OW Egg Mass Hawthorn, Crabapple, Cherry, Plum
European Pine Shoot,Moths Larva Pupa Pupa Adult Adult Adult Larva Larva OW Larva Scot's, Red, Mugo Pine
Fall Webworms Pupa Pupa Adult Egg Larva Larva Pupa Larva Ow Pupa Ash, Flowering Crab, Various Shade Trees
Forest Tent Caterpillars OW Egg Larva Larva Adult Adult OW Egg Mass Hawthorn, Crabapple, Cherry, Plum
Gypsy Moths OW Egg Mass Larva Larva Pupa Pupa Adult Adult OW Egg Mass Oak, Poplar, Birch, Maple & Conifers
Imported Willowleaf Beetles Adult Egg Larva Adult Egg Larva Pupa Adult Egg Larva Pupa Adult Larva Pupa Adult OW Adults Willow, Polar
Japanese Beetles Larva Larva Larva Pupa Adult Egg Egg Larva Adult OW Larva Rose, Linden, Cherry, Other Deciduous Plants
Oak, Birch, Apple Skeletonizers OW Pupa Adult Egg Larva Pupa Adult Egg Larva OW Pupa, Birch, Apple, Oaks
Pear Sawflies OW Larva,Pupa Pupa Adult Larva Pupa Adult Adult Egg OW Larva Hawthorn, Mountain Ash, Serviceberry Cherry, Pears, Quince
Satin Moths OW Larva OW Larva Pupa Adult Adult Egg Larva OW Larva Poplar, Willow, Oak, Aspen
Viburnum Leaf Beetles OW Egg Larva Larva Pupa Adult Adult OW Egg European Highbush, Cranberry, Arrowood Viburnum
White Marked Tussock Moths OW Egg OW Egg Larva Larva, Pupa Larva, Pupa, Adult Adult, OW Egg Many Deciduous Trees
Yellow Headed Spruce Sawflies Pupa Adult, Egg Adult, Egg Larva Larva OW Prepupa All Spruce

 

Sucking Insects

PestAprilMay JuneJulyAugustSeptHost Plant
Cottony Maple Scales Immature Female Adult Adult, Egg Crawler Nymph OW Nymph Maple, Black Locust, Oak, Sycamore
Crimson Erineum Mites Adult Egg Egg Larva Adult Egg Larva Adult Larva Adult Adult OW Adult Silver, Red, Sugar Maple
Euonymus Scales Mature Female Egg Crawler Crawler Nymph OW Nymph Euonymus, English Ivy, Lilac, Pachysandra
European Red Mites OW Egg Nymph Adult Egg Nymph Adult Egg Nymph Adult Egg Nymph Adult OW Egg Crabapple, Mountain Ash
Fletcher Scales Nymph Adult Adult Crawler Crawler Nymph OW Nymph White Cedar, Yew
Juniper Scales OW Adult, With Egg Egg Crawler Crawler Adult Adult OW Adult With Egg Juniper
Lecanium Scales Nymph Adult Crawler Crawler Nymph OW Nymph Ash, Boxwood, Cedar, Honey Locust, Oak, Yew
Magnolia Scales Nymph Nymph Nymph Adult Adult Crawler OW Nymph Saucer, Star Magnolia, Cucumber Tree
Oyster Scales OW Egg Crawler Crawler Nymph Adult Adult OW Egg Lilac, Crabapple, Dogwood, Linden, Cotoneaster
Pearleaf Blister Mites Adult Egg Nymph Adult Egg Nymph Adult Nymph Adult Adult OW Adult Serviceberry, Mountain Ash, Cotoneaster, Pear
Pine Needle Scales OW Egg OW Egg Crawler Nymph Crawler Nymph Adult OW Egg Mugo, Scots, Austrian, Pine, Spruce
Pine Tortoise Scales OW Nymph Adult Egg Adult Egg Crawler Crawler Nymph OW Nymph Scots, Austrian, Red Pine
Spruce Spider Mites OW Egg Egg Nymph Egg Nymph Adult Egg Nymph Adult Nymph Adult OW Egg Spruce, Cedar, Juniper, Hemlock
Two‑Spotted Mites OW Adult Egg Nymph Adult Nymph Adult Nymph Adult Nymph Adult OW Adult Numerous Plants
Cooley Spruce Gall Adelgids Nymph Nymph Nymph Nymph Adult OW Nymph Blue Spruce, Douglas Fir
Eastern Spruce Gall Adelgids Nymph Nymph Nymph Nymph Adult OW Nymph Norway & White Spruce, Englemann Spruce
Honeylocust Pod Gall Midges OW Adult Adult Egg Larva Adult Egg Larva Adult Egg Larva Adult OW Adult Honeylocust
Maple bladder Gall Mites Adult Egg Nymph Adult Egg Nymph Adult Adult Adult OW Adult Silver Maple, Red Maple
Maple Spindle Gall Mites Adult Egg Nymph Adult Egg Nymph Adult Adult Adult OW Adult Red Maple, Sugar Maple, Silver Maple

 

Borers

PestAprilMayJuneJulyAugustSept.Host Plant
Black Vine/ Strawberry Root WeevilsLarvaLarvaPupa AdultAdult Egg LarvaEgg Adult LarvaOW LarvaYew, White Cedar, Pine, Spruce, Hemlock, Euonymus, Rhododendron
Bronze Birch BorersLarvaLarva PupaPupaAdult EggAdult Egg LarvaOW LarvaBirch
Eastern Pine Shoot BorersPupaAdultEgg LarvaLarvaLarva PupaOW PupaPine
Lilac BorersOW LarvaPupaAdult EggAdult Egg LarvaEgg LarvaOW LarvaLilac, Ash
Locust BorersEggLarvaLarvaPupaAdultEgg AdultBlack Locust
Peach Tree BorersOW LarvaPupaAdult EggAdult Egg LarvaLarvaOW LarvaCherry, Purple Sandcherry, Peach, Other Prunus
Pine Root Collar WeevilsOW AdultAdult EggEgg Larva AdultEgg Larva AdultLarva AdultOW AdultScots, Austrian,Pine
Poplar Willow BorersLarvaLarvaLarvaAdultEgg AdultOW Larva AdultWillow, Poplar, Birch
Zimmerman Pine MothsLarvaLarvaLarvaLarva PupaAdult EggOW LarvaPine

Legend

OW = Over Wintering

Learn More

 


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 04 July 2005
Last Reviewed: 25 June 2010