PEST MANAGEMENT SUMMARY
Amy J. Dreves and Glenn Fisher; CSS Dept. Entomologists
June 24, 2008
Spring pest presence was evaluated every 7-14 days by Visual Inspections, Sweep Netting,
and Pod Inspections. Pest populations at canola seedling stage included: slugs, cucumber beetles,
and rabbits! However, these pests were very low and not causing economic injury to the plants.
Cucumber beetle numbers were highest in areas where volunteer rye was not controlled. Some new
seedlings close to the bordering shrubs and trees were heavily defoliated. Overwintering cabbage
maggot puparium emergence was delayed by 3 weeks and no evidence of excessive damage (< 5%)
was observed. We have been closely monitoring for the presence of seed pod weevils (SPW) beginning
flowering stage (See table 1). The threshold documented in Canada is two weevils per one 180° sweep.
We observed less than 1 per sweep throughout the season. We will evaluate SPW infestation in mature
pods during the last week in June.
Overall, the canola plants and pod development look good and vigorous at all sites in the Valley
(5 – 6 feet tall). However, some pods are poorly developed, most likely due to the cold weather, lack of
substantial rain and frost in April during flowering. Other pests observed thus far over the season include:
pollen beetles (highest numbers), flea beetles, thrips, and lygus bugs. Pollen adults are commonly seen
on oilseed rape flowers. They are unlikely to cause great damage to winter oilseed canola, but they are
greater threat to backward winter crops and to spring oilseed rape crops. In the spring, adult pollen
beetles fly to winter oilseed rape crops. They initially colonize the field margins before venturing further
into the crop. The beetles feed on pollen. This means they are of no threat to crops in flower, but at green
and yellow bud growth stages, they can damage the flowers. Spring canola tend to be at a greater risk of
damage from pollen beetles, which is why thresholds are different for winter and spring sown crops.
Crops at risk are those still at green-yellow bud where the beetles have to chew their way through the bud
to get at the pollen – this kills the bud leading to blind stalks as no flowers will consequently form. Healthy
well established winter oilseed canola would need 15 beetles per plant to warrant a treatment. Stressed
winter oilseed rape crops cannot cope with the added stress of pollen beetles, so these crops only need 5
beetles per plant at green-yellow bud to justify treatment. The threshold for spring canola when treatment
is required is one beetle per plant. No aphids have been seen on canola terminals this year, unlike last
year. It appeared that birds causing shattering are the biggest danger to canola at the Hyslop Farm. The
Canola Classic newsletter will be produced in July.
Location
2008
Mean no. of weevils
per ten, 180° sweeps
5/6
5/20 5/23 6/9
South of Valley
TILLED Site
2.7
2.3
2.1
1.7
3.2
--
2.8
1.9
3.4
2.5
1.8
0
--
--
--
0.5
PD: 27-Sept
South of Valley
NO-TILL Site
PD: 27-Sept
North of Valley
TILLED Site
PD: 25-Sept
Hyslop Farm
ODA Canola Update 6-24-08.doc
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Date
MAY and AUG
2007
SEPT 17, 2007
SEPT 24, 2007
JAN 9, 2008
May 28, 2008
Presentation/Talk/Newsletters Place
Produced 2 CANOLA
OSU Extension
CLASSIC newsletters
Newsletters; Crop
and Soil Science
Seed Pod Weevil Infestation in BILAT Canola
Cooperation for
R&D on cultural
and biological pest
control in field
vegetables
Canola and Root Crop Pests
IOBC Working
Group 'Integrated
Protection in Field
Crops'
What’s new with Canola grown PNW Insect
as a potential biofuel?
Management
Conference
The latest pest news on Canola Hyslop Field Day
in the Valley
ODA Canola Update 6-24-08.doc
2
Location
Oregon State Univ.
Corvallis OR USA
Oslo, Norway
Porto, Portugal
Portland, OR USA
Corvallis, OR USA
6/9/08 Good and poorly-developed pods.
ODA Canola Update 6-24-08.doc
3