Seasonal Pest Occurrence for Fruit and Vegetable Pests

 
 
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 Insect Pest Occurrence - Fruit | Insect Pest Occurrence - Vegetables | Seasonal Disease Occurrence - Fruit | Seasonal Disease Occurrence - Vegetables

There are a number of insect pests and plant diseases that may attack fruit and vegetable crops each season. Not all of them occur every year and the severity will also vary, depending on a number of factors. Understanding when an insect pest is at a vulnerable stage of development or when a disease is more likely to occur will allow management practices to be most effective, and will reduce ineffective and wasteful applications. Preventative and protective practices can be implemented, minimizing crop losses.

The following charts and tables represent general ranges of when pests (and their respective stages) may occur. It is important to recognize the depending on the region, the earliest, latest and average dates that stages occur may shift. In general, these dates are reasonable estimates for pests on the Canadian Prairies.

Seasonal Insect Pest Occurrence - Fruit Crops

For a PDF version of the following table - click here
For a PDF version of a graphic representation of the following table - click here

Pest Name
Host Crops
EGGS
LARVAE
NYMPHS
PUPAE
ADULTS
ALL STAGES
Aphids
Many
Apr to Sept
Apple Curculio
Saskatoon berry, chokecherry, crabapple, hawthorn & pear
June-July
mid-Apr to end-May / mid-July to end-Sept
Apple Maggot
Apple, crabapple, sweet/tart cherry, etc.
July
mid-July to Sept
Sept (overwinter)
late-June-early-July to end-Oct
Brown Marmorated Stink Bug
Wide range – over 300 different hosts – berries, grapes, stone & pome fruit
Early June until late July or early August
5 stages – throughout summer
Emerge May to June; stick around throughout season
Single generation per season
Note – most stages likely occur elsewhere than Alberta, at present – typically arrive as hitchhikers
Cherry Shoot Borer
Chokecherry, Saskatoon berry, hawthorn
mid-Apr to mid-May
mid-May to end-June
end-May to start-Aug
Chokecherry Fruit Gall Midge
Chokecherry, Saskatoon berry
mid-May to mid-July
Apr to mid-May
May to end-June
Currant Fruit Fly
Currants and gooseberries
late-May to early-July
early-June to July
Aug to overwinter
mid-May-early-June to late-June
Cyclamen Mite
Strawberry
ALL
(Mult gen)
Hawthorn Lace Bug
Saskatoon berry & other Rose family plants
May; mid-July to mid-Aug
mid-May to late-June / late-July to mid-Sept
Apr to mid-May / July to mid-Aug / mid-Sept+
Leafhoppers
chokecherry, Saskatoon berry, raspberry, strawberry
start-June to mid-June
May / mid-June to end-Sept
McDaniel’s Spider Mite
Saskatoon berry
ALL
(Mult gen)
Meadow Spittle Bugs
Strawberry, other non-fruit species
April to mid-May
late-May to mid-July
mid-late-June to mid-Aug
Pear Slug
Saskatoon berry, pin cherry, cotoneaster, hawthorn, chokecherry
late-June to end-Aug
Apr to early-June / mid-Aug to end-Sept
early-June to mid-July
Raspberry Crown Borer (2-YR LIFECYCLE)
Caneberries
Sept to Oct
Sept to Oct
early-Aug to end-Sept
All stages present in any one year
2ND YEAR
Apr to Sept
July
Raspberry Sawfly
Caneberries, gooseberry, etc.
June to early July (above ground); Late June to end-Sept (in soil)
April
Root weevils
Strawberry, raspberry, range of other crops
April; Mid-July to end-Sept
May to end-June
late-June to end-Aug
Saskatoon Bud Moth
Saskatoon berry
early-May to late-Aug
early-mid-April to early May; Sept
April to early-mid-May
Saskatoon / Chokecherry Sawfly
Saskatoon berry, chokecherry
early-June to early-Aug
April to mid-May
Mid-May to late June
Slugs
Strawberry + range of hosts
early-May to early-mid-July
mid-May to end-July
late-June to end-Sept
Spotted Wing Drosophila
Strawberry, caneberry, bushberries (blueberry, Saskatoon berry, etc.)
June to Sept
late-June to Sept
July to Sept
June to Sept (in some areas)
June to Sept
Strawberry Bud/Clipper Weevil
Strawberry; caneberries, other
mid-May to late-June
Apr to late-May / late-June to end-Sept
Tarnished Plant Bug / Lygus Bug
Strawberry
early-May to late-Aug
May; late-June to end-Sept
Raspberry
May to Aug
April to late-May; late-June to end-Sept
Thrips
Strawberry, caneberry, tree fruit, etc.
Overwinter in USA
mid-May to mid-Aug
Two-Spotted Spider Mites
Strawberry, raspberry, etc.
ALL
(Mult gen)
Ugly Nest Caterpillar
Chokecherry, pin cherry, etc.
April
May to Aug
late-June to end-Sept
Woolly Elm Aphid / Wooly Apple Aphid
Saskatoon berry, elm (alternate host)
April (on elm)
late-Apr to Sept (on Saskatoon); Aug to Sept (migrates to Elm)
May to Sept (some winged migratory stages)
* Note – occurrence timelines are estimates only and can vary according to seasonal conditions and other factors – use a general guideline
** See below for graphic representation of seasonal pest occurrence
*** Adapted and expanded from MAFRI Fruit Crop Insect Guide

Seasonal Insect Pest Occurrence - Vegetables

For a PDF version of the following table - click here
For a PDF version of a graphic representation of the following table - click here

Pest Name
Host Crops
Eggs
Larvae
Nymphs
Pupae
Adults
All Stages
Aphids
Many vegetable crops
May to Sept - Multiple generations
Aster Leafhopper
Many vegetable crops
early Spring or other crops in other regions; Multiple generations
Multiple generations per season - late July to end-Sept
Multiple generations - 1st generations late-May to early-June; June-Sept
May have 1-4 generations per season
Beet Webworm
Many vegetable crops
mid-May to July; mid-July to Sept
late-June to early July; late-Aug to Sept (overwinter)
late-May; Sept to overwinter
mid-May to July; mid-July to Sept
Brown Marmorated Stink Bug
Wide range – over 300 different hosts – peppers, tomatoes, corn, etc.
Early June until late July or early August
5 stages – throughout summer
Emerge May to June; stick around throughout season
Single generation per season
Note – most stages likely occur elsewhere than Alberta, at present – typically arrive as hitchhikers
Cabbage Looper
Cole crops + other cruciferous crops
July
mid-July onward
late-July to Aug
June-Sept
One generation per year
Cabbage Maggots
Cole crops + other cruciferous crops
mid-May to June; mid-July to Aug; late-Aug to Sept
June to July; Aug to Sept
mid-July; late Sept overwinter
May to Aug-Sept
1-3 generations per season
Colorado Potato Beetle
Plants in Solanaceous family
late-May to July
early-June to Aug
July to Aug
late-May-early-June to Sept; Overwinter as adult
All season; typically 1 complete generation per season
Crucifer Flea Beetles
Cruciferous crops
mid-May to June
late-May to July
mid-May to June; late-July to overwinter
Typically 1 generation per season
Cutworms
Range of host crops
Aug to mid-Sept
late-Apr to June; late-Sept to overwinter; most overwinter as larvae
May to early June; some overwinter as pupae
June-July (hibernate); late-Aug to Sept
Timing and duration of stages depends on the species
Diamondback moth
Cole crops + other cruciferous crops
mid-May to Sept
mid-May to Sept
June to Sept
early-May to Sept
Multiple generations per season
European Corn Borer
Corn, snap bean, potato, eggplant, pepper
late-July
late-July to overwinter pupation
May to June
late-June to early Aug
1 generation on Prairies
Imported Cabbageworm
Cole crops + other cruciferous crops
late-May to Sept
June to Sept
late-June to Sept; overwinter as pupae elsewhere
mid-May to Sept
2-3 generations per year
Onion Maggots
Bulb vegetables
June to early-July
June to early-Aug
Overwinter; late-July
late-May to June; repeats later in season
May be more than 1 generation per season
Pea Leaf Weevil
Peas
May to June
June to July
July
May to June; late-July to Aug (then overwinter)
1 complete generation per season
Swede Midge
Cole crops
mid-May to Sept
late-May to Sept
June to Sept
mid-May-early-June to Sept (multiple generations)
Multiple generations per season (in some areas)
Tarnished Plant Bug / Lygus Bug
Many vegetable crops
May to July
end-May to Aug
late-Apr to Sept; overwinter
Multiple generations per season
Tuber Flea Beetles
Potatoes
mid-May to June
June to July
mid-May to June; late-July to overwinter
Typically 1 generation per season
Two-Spotted Spider Mites
Bean, cucurbits, eggplant
April to late-Sept
Overwinter to Sept
Multiple generations per season
Wireworms
Range of host crops
May
all season - several years
May
Life cycle spans several years
* Note – occurrence timelines are estimates only and can vary according to seasonal conditions and other factors – use a general guideline
** See below for graphic representation of seasonal pest occurrence
*** Prepared with contributions from Dr. Ken Fry, Olds College

Seasonal Disease Occurrence - Fruit

For a PDF version of the following table - click here

Pest Name
Host Crops
Causal Organism
Mode of Carryover
Mode of Transfer
Seedlings
Roots
Branches / Canes
Foliage
Flowers
Fruit
Entomosporium Leaf & Berry Spot
Saskatoon berry
Entomosporium mespili
Unknown - lesions on infected plant parts; in debris
Spores
-
-
Y - insignif
Y
Y
Y
Mummyberry
Saskatoon berry
Monilinia amelanchiaris
mummified fruit
spores
-
-
-
sometime
Y
Y
Saskatoon berry / Juniper Rust
Saskatoon berry (juniper = secondary host)
Gymnosporangium mespili
spore stages on alternate host (juniper)
spores from junipers; spores on saskatoon berry
-
-
-
Y
-
Y
Blackleaf / Witches’ Broom
Saskatoon berry
Apiosporina collinsii
Infected plant material (wild, etc)
Spores
-
-
Y
Y
-
indirect-Y
Fireblight
All plants within Rosaceae (saskatoon berry, apple, etc.), caneberries
Erwinia amylovora
branch cankers
insects, rain / water splash, Physical transfer (pruning)
-
-
Y
Y
Y
N - indirect
Botrytis grey mold
Strawberry, raspberry, etc.
Botrytis cinerea
infected plant material; sclerotia; spores
spores
Y
-
Y
Y
Y
Y
Powdery Mildew
Strawberry, Saskatoon berry, raspberry, black currants
Spaerotheca macularis f.sp fragariae; Podosphaera clandestina;
cleistothecia (sexual spores)
windblown spores
-
-
Y
Y
-
Y
Pythium root rots
Strawberry, raspberry, etc.
Pythium spp.
soil borne mycelium, sporangia, oospores
germinating oospores
Y
Y
-
Y - seedlings - indirect
-
-
Cane Blight
Caneberries
Leptosphaeria coniothyrium
lesions on infected canes
spores
-
-
Y
Y
Y-indirect
N-indirect
Spur Blight
Caneberries
Didymella applanta
lesions on infected canes
spores
-
-
Y
Y
Y-indirect
N-indirect
Common Leaf Spot
Strawberry
Mycosporaella fragariae
infected plant material (in field, propagative material)
spores - rain or mechanical transfer
-
-
-
Y
-
Y- black seed
Black Knot
Prunus spp.
Apiosporina morbosa
Galls
Spores produced on infected wood
-
-
Y
indirect
-
-
Brown Rot / Cherry Blossom Blight
Prunus spp.
Monilinia spp.
mummified fruit; infected plant parts
spores disseminated by wind, rain, insects
-
-
Y - twigs
-
Y
Y
Cytospora canker
Saskatoon berry; other crops (dif spp.)
Cytospora leucostoma
cankers in infected tissues
via wounds
-
-
Y
Y-indirect
-
-
Root rots
Raspberry, etc.
Fusarium, Rhizoctonia, etc
soil borne
soil to plant
Y
Y
-
N- indirect
-
-
Black Root Rot
Strawberry
Rhizoctonia, Pythium, etc.
soil borne; infected plant stock
soil to plant
Y
Y
-
N- indirect
-
-
Verticillium Wilt
Strawberry, raspberry, other fruit
Verticillium albo-atrum; V. dahliae
microsclerotia or mycelium on crop debris or in soil
spores or spores in soil
Y
Y
Y - indirect
Y - indirect
-
-

Pest Name
Timing
Control
Storage
Entomosporium Leaf & Berry Spot
Foliar infection can occur throughout summer; Fruit infection from flowering to harvest
Protective sprays
N
Mummyberry
May to June (during bloom)
Remove inoculum; protective sprays
N
Saskatoon berry / Juniper Rust
June to August
Apply protective sprays; control on junipers
N
Blackleaf / Witches’ Broom
Infection of new growth in spring
Pruning in dormant season
N
Fireblight
Throughout growing season once active growth commences
Prune out diseased material
N
Botrytis grey mold
Can occur at any point in growing season
Remove debris; Protective sprays
Y
Powdery Mildew
Spring or fall
Ensure air movement; fungicide application
N
Pythium root rots
early season or whenever young plants are present
good drainage; seed treatments
N
Cane Blight
mid-late season; depends on environmental conditions
Protective sprays
N
Spur Blight
mid-late season; depends on environmental conditions
Protective sprays
N
Common Leaf Spot
Early season or late summer
Clean plants; adequate air flow; protective sprays
N
Black Knot
infection occurs in early spring
Pruning in dormant season
N
Brown Rot / Cherry Blossom Blight
During bloom & fruiting stages
Remove inoculum; protective sprays
N
Cytospora canker
Can occur at any point in growing season
Remove infected tissues
N
Root rots
Depends on the weather
Clean plants; good drainage
N
Black Root Rot
Depends on the weather
Clean plants; good drainage
N
Verticillium Wilt
Dependant on weather & crop stage
seed, soil treatment; clean plants
N

Seasonal Disease Occurrence - Vegetables

For a PDF version of the following table - click here

Pest Name
Host Crops
Causal Organism
Mode of Carryover
Mode of Transfer
Seedlings
Roots
Stems / Branches
Foliage
Flowers
Fruit
Seeds
Tubers
Aster Yellows
Wide range
mycoplasma-like organism
Infected host plants
Aster Leafhopper
Y
Y
Y
Y
Y
Y
-
-
Bacterial Soft Rot
Wide range
Erwinia carotovora subsp carotovora or atroseptica
soil borne
via wounds/weak points; in storage, wash water;
N
Y
Y
Y
N
Y
N
Y
Botrytis
Wide range
Botrytis cinerea
spores; mycelium; sclerotia
spores; mycelium
Y
-
-
Y
Y
Y
-
-
Clubroot
Cruciferous crops
Plasmodiophora brassicae
resting spore in soil
germinating resting spores; transfer of spores in water, soil, etc.
Y
Y
-
indirect - stunting
-
-
-
-
Common Blight
Beans
Xanthomonas campestris pv phaseoli
infected seed; contaminated soil
rain splash; physical contact; insects, etc
-
-
-
Y
-
Y
Y
-
Common Scab
Potato, beets, carrots, turnips, rutabaga, radish
Streptomyces scabies
Soil borne; infected seed
soil to tuber (via lenticels)
-
-
-
-
-
-
-
Y
Downy Mildew
Beets, spinach, cole crops, radish, rutabaga/turnip, lettuce, rhubarb, onion, garlic, peas
Perenospora spp. (depends on host crop)
oospores in soil, debris, plant parts
spores - water splash, wind
Y
Y - crown infect
-
Y
-
-
-
-
Early Blight
Potato, tomato, pepper, eggplant
Alternaria solani
Soil, crop residues, alternate hosts
spores - soil to tissue transfer; rain splash
-
-
-
Y
-
Y
-
Y
Fusarium dry rot
Potato
Fusarium sambucinum, F. solani, F. coeruleum, F. avenaceum
contaminated soil or infected seed
wounds
-
-
-
-
-
-
-
Y
Halo Blight
Beans
Pseudomonas syringae pv phaseolicola
infected seed; contaminated soil
rain splash; physical contact; insects, etc
-
-
-
Y
-
Y
Y
-
Late Blight
Potato, tomato, pepper, eggplant
Phytophthora infestans
On living tissues (tubers, etc)
sporangia; rain splash; on storm fronts
Y
-
-
Y
-
Y
-
Y
Neck rots
Bulb vegetables
Botrytis aclada, B. byssoidea, B. squamosa
Sclerotia in bulbs, debris, cull piles, volunteers, soil
spores via air; wounding at harvest
-
-
-
Y - bulbs
-
-
-
-
Pink Rot
Potato
Phytophthora erythroseptica
soil borne
infection of stolons, eyes, lenticels; via wounds at harvest
-
-
-
-
-
-
-
Y
Powdery Mildew
cruciferous crops, peas, lettuce, rhubarb, cucurbits
Erysiphe polygoni; E. cichoracearum
cleistothecia (sexual spores)
windblown spores
-
-
Y
Y
-
Y
-
-
Pythium root rots
Wide range
Pythium spp.
soil borne mycelium, sporangia, oospores
germinating oospores
Y
Y
-
Y - seedling - indirect
-
-
-
-
Rhizoctonia / Black Scurf
Potato
Rhizoctonia solani
sclerotia in soil or on seed tubers
soil to plant parts
Y
Y
Y
-
-
-
-
Y
Sclerotinia rot
Carrots, lettuce, beans, cole crops, potatoes, peas, cucurbits, solanaceous crops, etc.
Sclerotinia sclerotiorum
sclerotia in soil or on plant debris
spores; germinating sclerotia
Y
Y
Y
Y
-
-
-
-
Slippery Skin
Bulb vegetables
Pseudomonas gladioli pv. allicola
soil borne
rain splash of soil; via wounds
-
-
Y - neck area
Y - bulbs
-
-
-
-
Silver Scurf
Potato
Helminthosporium solani
in soil or in debris in soil
soil to tuber
-
-
-
-
-
-
-
Y
Verticillium Wilt
Potato, tomato, pepper, eggplant, cucurbit crops
Verticillium albo-atrum; V. dahliae
microsclerotia or mycelium on crop debris or in soil
spores or spores in soil
Y
Y
Y - indirect
Y - indirect
-
-
-
-

Pest Name
Storage
Timing
Control
Aster Yellows
N
June to Sept
Control insect vector
Bacterial Soft Rot
Y – spreads
Typically post-harvest
crop rotation; careful post-harvest handling;
Botrytis
Y
any point in the growing season with suitable conditions
Adequate fertilizer; protective sprays; timely harvests
Clubroot
N
any point in summer - typically in early summer
Rigorous sanitation; Long rotations; Avoid contamination
Common Blight
N
any point in summer
Use clean seed; bury residues
Common Scab
Visible; does not spread or increase
Infection occurs during 5 weeks (flowering onward)
Clean seed; seed treatments; even watering; variety selection
Downy Mildew
N
Dependant on weather
Crop rotation; bury debris; protective sprays
Early Blight
Y - does not spread
mid-late summer
Crop rotation; protective sprays; avoid plant stress
Fusarium dry rot
Y; does not spread
Wounding during harvest or post-harvest
Careful handling during harvest & post-harvest
Halo Blight
N
any point in summer
Use clean seed; bury residues
Late Blight
Y
any point in summer - depends on point of infection
Monitoring/early detection; protective sprays; clean seed potatoes
Neck rots
Y - increases in severity & as symptomless bulbs develop
mid-late summer to harvest
Reduce inoculum; avoid wounding; cure after harvest
Pink Rot
Y - spreads in storage
late summer; at harvest
Crop rotation; Cull after harvest; fungicides applied around planting or tuber set
Powdery Mildew
N
Spring or fall
Good airflow; crop rotation; remove inocululm
Pythium root rots
N
early season or whenever young plants are present
good drainage; seed treatments
Rhizoctonia / Black Scurf
Y - visible - doesn't increase or spread
early spring or late season
seed treatments; good growing conditions
Sclerotinia rot
Y
any point in summer
Remove inoculum; protective sprays; post-harvest management
Slippery Skin
Y - doesn't spread
mid-late summer
careful irrigation; proper post-harvest handling
Silver Scurf
Y
Before or at harvest
Seed treatments; quick harvest; cold storage
Verticillium Wilt
N
Dependant on weather & crop stage
seed, soil treatment; clean plants
Note – occurrence timelines and disease attack points are estimates only and can vary according to seasonal conditions and many other factors – use a general guideline

 
 
 
 
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This information published to the web on June 16, 2017.