Pest | Control threshold | Sampling recommendation | Additional notes |
---|---|---|---|
Mites: Redlegged earthmite (RLEM) Balaustium mite (BOM) Clover mite | If more than 50% of cotyledons are bleached white and the first true leaf is also being damaged apply control. 10 mites per 100cm² | Estimate the number of mites/100cm (10 x 10 cm) around the base of the plant (on weeds, soil and seedlings). Repeat at 5 – 10 sites. Avoid sampling in bright light, sample on cloudy days, early morning or late afternoon. | RLEM and BOM can occur in mixed populations. The two species have different susceptibilities to chemical sprays. Determine the species composition of the population before making spray decisions |
Aphids: More commonly Green peach aphid, Cabbage aphid and Turnip aphid | At least 20 % of plants with 25 mm, or more stem infested. Moisture stresses seedlings not able to compensate for damage | Sample crops twice weekly during flowering and podding. Inspect crops regularly through winter and early spring | Always determine the level of natural enemy activity when making control decisions about aphids. Early aphid infestations are of greater significance on terms of potential damage |
Caterpillars: Cutworm | 2-3 cutworm/m² | Early detection of larvae or plant damage essentail. Examine plants, old litter and soil surface in 0.5 m of row. repeat at 5 - 10 sites | Autumn - winter active |
Caterpillars: Brown pasture looper | 10 - 12 loopers/m² | On crop and weeds especially capeweed | NA |
Caterpillars: Diamondback moth | 1 caterpillar per canola seedling can cause crop damage | On leaves and when touched fall down on silk thread. | NA |
Caterpillars: Cabbage moth | Only count caterpillars longer than 3 - 4 mm | Mid to late flowering: 17 - 23 / 10 plants Pod maturation: 43 - 57 / 10 plants. Walk through the crop in a circular pattern. Start 10 - 15 m in from crop edge. Stop at 20 - 25 m intervals and randomly select a plant. Pull trhe plant up and shake into a sweep net (fold larger plants in half to shake). Count cabbage moth larvae longer than 3 - 4mm | Rainfalls greater than 5 - 8 mm in 24 hours will reduce the number of larve in the crop. If populations are approaching the threshold prior to such rainfall, sample again before making a decision to spray |
Lucerne flea | Ave. 10 holes/leaf at 5-10 sites are observed | Inspect 0.5 m of crop row. Look for characteristic holes in leaves | NA |
Beetles: False wireworms Bronze field beetle | 5 of more adults per m² can produce damaging numbers of larvae | Under crop residues close to soil surface especially around plants | Inspect paddocks in spring into which canola will be sown the following season |
Beetles: Vegetable beetle | 1 beetle per canola seedling | On ground in close proximity to seedling | NA |
Beetles: Weevils: Desiantha weevil Fuller's rose weevil Small lucerne weevil Vegetable weevil | 5 weevils per m² | Adult weevils hide under surface debris during the day. Vegetable weevil larvae can be found in growing points, leaf axils and under leaves | NA |
Rutherglen bug | 5 or more nymphs per canola seedling at the cotyledon or 2 leaf stage | Inspect canola crops regularly from flowering to windrowing. Inspect heads visually, or by shaking into a bucket. Examine 20 heads Repeat at 5 - 10 sites | Rutherglen bugs move into crops as host weeds, e.g. capeweed |
European earwig | 1 earwig per canola seedling can cause extensive crop damage | On plants at night or hidden under clods, trash or objects by day | NA |
Slaters: Various species | Seedlings not able to out-grow damage | Found at base of seedlings at night or under stubble, dead organic matter by day | NA |
Slugs: Black keeled slug Reticulated slug | 1 or more slugs per m² | Detect incidence early in the season using shelter traps e.g. moist hessian bags laid on the soil | NA |
Snails: Pointed snails | Pointed snails = 20 per m² | A management plan for the year starting soon after harvest is needed to avoid damage and contaimination | NA |
Snails: White Italian snails Vineyard snails | White Italian snail and Vineyard snail - 5 per m² | A management plan for the year starting soon after harvest is needed to avoid damage and contaimination | NA |
Canola - Insect threshold levels
See also
Further information
Page last updated: Friday, 17 April 2015 - 11:45am