Flea beetles

Flea Beetles (Chrysomelidae: Phyllotreta species) – The Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for "shot-hole" feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.  Link here to review photos and scouting tips for flea beetles in canola (Wk03).

Figure 1.  Flea beetle feeding on leaves canola seedling resulting in "shot-hole" damage plus girdling of stem (left) plus dorsal view of striped flea beetle (right).

Flea beetles

Flea Beetles (Chrysomelidae: Phyllotreta species) – Check the latest Canola Watch May 13, 2020 article describing flea beetles feeding on volunteers which also links to management tips for flea beetles in canola. 

As canola seedlings emerge, scout for flea beetle damage on cotyledons but also on the stem (Fig. 1, left).  Two species, Phyllotreta striolata (Fig. 1, right) and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola seedlings.  

Figure 1.  Flea beetle feeding on leaves canola seedling resulting in "shot-hole" damage plus girdling of stem (left) plus dorsal view of striped flea beetle (right).

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for "shot-hole" feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to 
flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings 
(Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page within the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" (Philip et al. 2018) as an English-enhanced or French-enhanced version.

Flea beetles

Flea Beetles (Chrysomelidae: Phyllotreta species) – As canola seedlings emerge, scout for flea beetle damage on cotyledons but also on the stem (Fig. 1, left).  Two species, Phyllotreta striolata (Fig. 1, right) and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola seedlings.

Figure 1.  Flea beetle feeding on leaves canola seedling resulting in "shot-hole" damage plus girdling of stem (left) plus dorsal view of striped flea beetle (right).

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for "shot-hole" feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to 
flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings 
(Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page within the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" (Philip et al. 2018) as an English-enhanced or French-enhanced version.

Flea beetles (May 16, 2019; Wk 06)

Flea Beetles (Chrysomelidae: Phyllotreta species) – As newly seeded stands begin to emerge, the need for in-field scouting increases.  Review Wk05 for flea beetle information, visual guides to help estimate percent of cotyledon damage, and links to the Insect Field Guide.  

This week we also link to Canola Watch which released flea beetle scouting and management tips for canola.  Provincial entomologists, flea beetle researchers and Canola Council of Canada specialists all provided input into this article.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Flea beetles (May 9, 2019; Wk 05)

Flea Beetles (Chrysomelidae: Phyllotreta species) – Reminder - Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.  Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to 
flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings 
(Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.

Flea beetles (May 2, 2019; Wk 04)

Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.  Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to 
flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings 
(Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.

Flea beetles (Aug 16, 2018; Wk 15)

Flea Beetles (Chrysomelidae: Phyllotreta species) – By early pod stages in canola, newly eclosed adult flea beetles begin to emerge from the soil.  These individuals typically feed then move away from canola fields to locate overwintering habitats.  

Normally, it can be difficult to locate these newly emerged adults but every few years they are easily observed among canola pods.  These adults can feed on upper leaves and nip at the exterior of canola pods but are typically observed in low densities - too low to cause economic damage.  Even so, be watchful - areas with high numbers of flea beetles late in the growing season are worthwhile to scout early in 2019.  

Remember - the Action Threshold for flea beetles on canola is 25% of COTYLEDON LEAF AREA consumed.  

Normally, it is NOT recommended to apply foliar insecticides for flea beetles in canola during the pod stages for the following reasons:

• Flea beetles are very mobile at this point in the season,
• Canola canopy is very thick,
• Growers must be cautious about pre-harvest intervals,
• PLUS, little is understood about overwintering survival of this pest!

Reminder - Earlier this season, the Insect of the Week featured flea beetles!

Refer to the flea beetle page from the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.

Previous Posts (Aug 02, 2018; Wk 13)

The following is a list of 2018 Posts - click to review:

Abundant parasitoids in canola - Week 10 
Alfalfa weevil - Week 6

Cabbage seedpod weevil - Week 12 
Cabbage root maggot - Week 11 
Cereal aphid manager (CAM) - Week 2
Cereal leaf beetle larvae request - Week 8
Crop protection guides - Week 2
Cutworms - Week 4

Diamondback moth - Week 7
Download the field guide - Week 10

Field heroes - Week 8
Flea beetles - Week 4

Monarch migration - Week 8

PMRA Pesticide Label Mobile App - Week 4

Scouting charts (canola and flax) - Week 3

Ticks and Lyme Disease - Week 4

Weather radar - Week 3
Wheat midge - Week 12

White grubs in fields - Week 8

Wind trajectories - Week 6
Wireworm distribution maps - Week 6

Previous Posts (Jul 26, 2018; Wk 12)

The following is a list of 2018 Posts - click to review:

Abundant parasitoids in canola - Week 10
Alfalfa weevil - Week 6

Cabbage seedpod weevil - Week 8 
Cabbage root maggot - Week 11 
Cereal aphid manager (CAM) - Week 2
Cereal leaf beetle - Week 5
Cereal leaf beetle larvae request - Week 8
Crop protection guides - Week 2
Crop reports - Week 8
Cutworms - Week 4

Diamondback moth - Week 7
Download the field guide - Week 10

Field heroes - Week 8
Flea beetles - Week 4

Monarch migration - Week 8

Pea leaf weevil - Week 8
PMRA Pesticide Label Mobile App - Week 4

Scouting charts (canola and flax) - Week 3

Ticks and Lyme Disease - Week 4

Weather radar - Week 3
White grubs in fields - Week 8
Wind trajectories - Week 6
Wireworm distribution maps - Week 6

Previous Posts (Jul 19, 2018; Wk 11)

The following is a list of 2018 Posts - click to review:

Abundant parasitoids in canola - Week 10Alfalfa weevil - Week 6

Cabbage seedpod weevil - Week 8 
Cereal aphid manager (CAM) - Week 2
Cereal leaf beetle - Week 5
Cereal leaf beetle larvae request - Week 8
Crop protection guides - Week 2
Crop reports - Week 8
Cutworms - Week 4

Diamondback moth - Week 7
Download the field guide - Week 10

Field heroes - Week 8
Flea beetles - Week 4

Monarch migration - Week 8

Pea leaf weevil - Week 8
PMRA Pesticide Label Mobile App - Week 4

Scouting charts (canola and flax) - Week 3

Ticks and Lyme Disease - Week 4

Weather radar - Week 3
Wind trajectories - Week 6
Wireworm distribution maps - Week 6
White grubs in fields - Week 8

Previous Posts (Jul 05, 2018; Wk 09)

The following is a list of 2018 Posts - click to review:

Alfalfa weevil - Week 6

Cabbage seedpod weevil - Week 8 
Cereal aphid manager (CAM) - Week 2
Cereal leaf beetle - Week 5
Cereal leaf beetle larvae request - Week 8
Crop protection guides - Week 2
Crop reports - Week 8
Cutworms - Week 4

Diamondback moth - Week 7

Field heroes - Week 8
Flea beetles - Week 4

Monarch migration - Week 8

Pea leaf weevil - Week 8
PMRA Pesticide Label Mobile App - Week 4

Scouting charts (canola and flax) - Week 3

Ticks and Lyme Disease - Week 4

Weather radar - Week 3
West nile virus - Week 8
Wind trajectories - Week 6
Wireworm distribution maps - Week 6
White grubs in fields - Week 8

Flea beetles (May 31, 2018; Wk 04)

Flea Beetles (Chrysomelidae: Phyllotreta species) – The Insect of the Week features flea beetles!

Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.  Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to 
flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings 
(Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.

Insect of the Week (May 28, 2018) - Flea Beetles

This week's Insect of the Week is the Flea Beetle (Phyllotreta species). This group of beetles is typically oval and 2-3 mm long.  In canola, the most common flea beetles are either bluish black (crucifer flea beetle or Phyllotreta cruciferae) or black with two wavy yellow lines running down the length of its back (striped flea beetle or Phyllotreta striolata). They overwinter as adults under plant material along field margins and females lay eggs in the soil near the host plants. 

Striped and crucifer flea beetles feed on canola, mustard and related cruciferous plants and weeds. Their damage results in a shot-hole appearance in cotyledon leaves. They also feed on stems under windy or damp conditions, causing wilting or breakage. Remember, the Action Threshold for flea beetles on canola is when 25% of cotyledon leaf area is consumed. 

For more information on flea beetles, refer to the Insect of the Week page!

Crucifer flea beetle and damage
Photo: AAFC

Flea beetle damage on cotyledon
Photo: Mike Dolinski, MikeDolinski@hotmail.com



Flea beetles (May 24, 2018; Wk 03)

Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.  Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to 
flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings 
(Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.

Flea beetles (May 17, 2018; Wk 02)

Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.  Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to 
flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings 
(Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.

Flea beetles (May 10, 2018; Wk 01)

Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.  Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to 
flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings 
(Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.

Update from the field....

Canola growers at the far south of Alberta will want to note this preliminary update kindly provided by Dr. H. Carcamo (AAFC-Lethbridge) on July 20, 2017 related to flea beetles in canola.....

"We just collected sticky cards from a canola field just east of Stirling that is part of a collaborative study led by Dr. Alejandro Costamagna. I noticed an unusual dominance by striped flea beetles in this field. 15 years ago only 1 out of a 1000 flea beetles would have been striped and the rest crucifer, however, the two fields we sampled today near Stirling AB were unusual.  Approximately 48% of the flea beetle population trapped on sticky cards in the one field were striped flea beetles and a second canola field had ~71% striped flea beetles."

Dr. Carcamo goes on to caution that the above observation was based on only a single week of sticky card monitoring.  Stay tuned because the entire seasonal data set from these two sites will warrant careful scrutiny!  Even so, this update is an excellent example of the importance of in-field scouting and the value of ongoing data collection!

Review previously posted information about flea beetles in canola here.

Weekly Update (Jun 1, 2017; Wk 05) - Flea beetles

Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.  Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to 
flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings
 (Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the new "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.

Weekly Update (May 25, 2017; Wk 04) - Flea beetles

Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.  Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  - take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the new "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.