2012 Peace River Region Annual Canola Survey J.Otani1

1 Research Farm, Agriculture & Agri-Food , P.O. Box 29, Beaverlodge AB, [email protected]. 2 Saskatoon Research Centre, Agriculture & Agri-Food Canada, 107 Science Place, Saskatoon SK. 3 Smoky Applied Research and Demonstration Association, AB.

The 2012 Annual Peace Canola Survey was completed by Agriculture & Agri-Food Canada staff based at Beaverlodge and Saskatoon with additional help from Smoky Applied Research and Demonstration Association3 (SARDA) staff at Falher, . The survey has been performed since 2003 with the main objectives of collecting canola insect pest data throughout the region and to detect introduction of the Cabbage seedpod weevil into the Peace River region. A total of 168 canola fields were surveyed throughout the BC and Alberta Peace during flowering with random sampling performed between July 6-11, 2012. Sweep-net sampling was conducted by performing 50 - 180° sweeps per canola field (N=1 B. rapa + 167 B. napus) on the following dates in these areas:  July 6 near and Beaverlodge.  July 7 near Dawson Creek, Rolla, Clayhurst, Goodlow, Cecil Lake, Fort St. John, Montney, Rose Prairie, Baldonnel, Taylor, and Farmington BC.  July 9 near Valleyview, , Debolt, Bezanson, Beaverlodge, Hythe, Valhalla, LaGlace, Sexsmith, , Wembley.  July 10 near Woking, Spirit River, Bonanza, Silver Valley, Blueberry Mountain, Rycroft, Fairview, , Worsley, Grimshaw, Peace River, Manning, Hotchkiss, Paddle Prairie, , , , Whitemud Crossing, , McLennan, Falher.  July 11 near Beaverlodge, Valhalla, and LaGlace. Sexsmith, , Wanham, Eaglesham, , Tangent, Nampa, Jean Côté, Falher, Girouxville, , Fort Vermilion, LaCrête, Buffalo Head Prairie, Carcajou, Deadwood.

The 2012 summary includes five economically important pests of canola:

1. Lygus bug (Miridae: Lygus spp.) populations of ≥5 lygus bugs per 10 sweeps were observed in 32 fields surveyed (N=168 fields). Early instar nymphs were present in 100 fields surveyed yet ≥5 nymphs per 10 sweeps were observed in only eight fields (i.e., surveyed near Deadwood, LaCrete, Sexsmith, High Level, Fort St. John, Worsley, Taylor, Marie Reine, and Hines Creek). Note that all nymphs collected during surveying will have matured into new adults since July 11, 2012. Refer to the 2012 Lygus Survey Map but remember individual fields must be monitored because Lygus bug populations can vary drastically.

Lygus bugs per 10 sweeps Number of fields Percent of fields sampled ≥15.0 4 2% 10.1-15.0 5 3% 5.1-10.0 23 14% 0.1-5.0 125 74% 0 11 7% Totals 168 100%

Lygus bug stage Number of individuals Percent of lygus bugs sampled Adult 1790 68.9% 4-5 instar 261 10.0% 1-3 instar 547 21.1% Totals 2598 100.0%

The economic threshold for lygus bugs is applicable at the late flower and early pod stages but varies according to current crop value and control costs.

Table 1. Economic thresholds for lygus bugs in canola at late flowering and early pod stages (Wise and Lamb 1998).

Control costs Late flower to early pod (Canola crop stages 4.4-5.11) $/ac $/ha Economic Injury Level2 $8.00 $19.77 8 6 5 4 4 3 3 $10.00 $24.71 10 8 7 6 5 4 4 $12.00 $29.65 12 9 8 7 6 5 5 $14.00 $34.59 14 11 9 8 7 6 5 $16.00 $39.54 16 13 10 9 8 7 6 $18.00 $44.48 18 14 12 10 9 8 7 $20.00 $49.42 20 16 13 11 10 9 8 Canola $/bu $8.00 $10.00 $12.00 $14.00 $16.00 $18.00 $20.00 value $/tonne $352.42 $440.53 $528.63 $616.74 $704.85 $792.95 $881.06 1 Canola crop stage estimated using Harper and Berkenkamp 1975). 2 Economic thresholds are based on an assumed loss of 0.1235 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).

Table 2. Economic thresholds for lygus bugs in canola at pod stage (Wise and Lamb 1998).

Control costs Late pod (Canola crop stages 5.21) $/ac $/ha Economic Injury Level3 $8.00 $19.77 11 9 7 6 5 5 4 $10.00 $24.71 14 11 9 8 7 6 5 $12.00 $29.65 16 13 11 9 8 7 7 $14.00 $34.59 19 15 13 11 10 9 8 $16.00 $39.54 22 18 15 13 11 10 9 $18.00 $44.48 25 20 16 14 12 11 10 $20.00 $49.42 27 22 18 16 14 12 11 Canola $/bu $8.00 $10.00 $12.00 $14.00 $16.00 $18.00 $20.00 value $/tonne $352.42 $440.53 $528.63 $616.74 $704.85 $792.95 $881.06 3 Economic thresholds are based on an assumed loss of 0.0882 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).

2. Diamondback moth (Plutellidae: Plutella xylostella) were present in low densities in 2012. Sweep-net monitoring is NOT advised for this insect pest but DBM larvae were present in 143 of the 168 fields surveyed. Two important surveying notes for this pest include: (i) No surveyed field exhibited economically significant DBM damage, and (ii) parasitoid wasps known to attack DBM were observed at most sites surveyed. Remember, sweep-net sampling provides a general estimate and is not a valid sampling method for this pest in canola. Refer to the 2012 survey map for our sweep-net densities.

Diamondback moth + Number of fields Percent of fields sampled larvae per 10 sweeps ≥15.0 1 1% 10.1-15.0 5 3% 5.1-10.0 14 8% 0.1-5.0 123 73% 0 25 15% Totals 168 100%

Diamondback Number of individuals Percent of Diamondback stage sampled Larvae 1485 90.3% Adults 159 9.7% Totals 2598 100.0%

Diamondback moth larvae will feed on the exterior of canola pods during the early pod stage. Damaged pods are prone to shattering, particularly under dry, hot, windy conditions. The action threshold for DBM larvae is 20-30 larvae per 1/10m2 (approximately 2-3 larvae per plant).

3. Grasshoppers were present in only 17 canola fields during surveying (densities ranged up to 1.0 grasshoppers per 10 sweeps). Two-striped, lesser migratory species were present in the grass ditches at several sites but high densities were present (e.g. >40/m2) in the BC Peace near Goodlow, Cecil Lake, Montney, and Rose Prairie.

4. Bertha armyworm were NOT observed in our sweeps. Pheromone trap counts peaked the same week surveying was performed so larvae were not expected or detected in our sweep-net samples. Producers near areas that experienced high pheromone trap catches should be monitoring now for BAW larvae in their canola fields.

Table 1. Economic thresholds for Bertha armyworm in canola (courtesy Manitoba Agriculture, Food and Rural Initiatives). Expected Seed Value - $ / bushel* Spraying 6 7 8 9 10 11 12 13 14 15 16 cost – Number of Larvae / metre2 * $ / acre 7 20 17 15 13 12 11 10 9 9 8 8 8 23 20 17 15 14 13 11 11 10 9 9 9 26 22 19 17 16 14 13 12 11 10 10 10 29 25 22 19 17 16 14 13 12 11 11 11 32 27 24 21 19 17 16 15 14 13 12 12 34 30 26 23 21 19 17 16 15 14 13 13 37 32 28 25 22 20 19 17 16 15 14 14 40 35 31 27 24 22 20 19 17 16 15 15 43 37 32 29 26 23 22 20 19 17 16 * Economic thresholds for bertha armyworm are based on an assumed yield loss of 0.058 bu/acre for each larva/metre2 (Bracken and Bucher. 1977. Journal of Economic Entomology. 70: 701-705).

5. We are again happy to report that zero cabbage seedpod weevil (Curculionidae: Ceutorhynchus obstrictus) were observed in the 168 fields sampled in the Peace River region in 2012. A single Ceutorhynchus specimen suspected to be C. neglectus has been sent to taxonomists at the Canadian National Collection (AAFC-Ottawa) for species confirmation.

Thank you to our canola producers for allowing us to sample in their fields. Thank you to the following dedicated staff who surveyed†, processed‡, and mapped∞ this data: Holly Spence1†‡, Arlan Benn1†‡, Kayleigh Loberg1†‡, Alice Lee1†‡, Owen Olfert2†∞, Ross Weiss2†∞, David Owens3†, Jennifer Reade 3†, JP Petitjean3†, and David Giffen2∞.