Canola Seedlings Research Articles

Canola–Wheat Intercrops for Improved Agronomic Performance and Integrated Pest Management

Intercropping can enhance yields and reduce pest infestations, but investigations of intercropping regimes using crop species common to the large‐scale monoculture production systems of western Canada have not examined these diverse elements. Intercrops of canola (Brassica napus L.) and wheat (Triticum aestivum L.) were established at three sites in Alberta, Canada in 2005 and 2006 to determine interactions between intercropping regimes and crop grain and biomass yield, crop quality characteristics, soil microbial community biomass and diversity, flea beetles (Phyllotreta spp., Coleoptera: Chrysomelidae), and wheat leaf diseases. The study also investigated effects on flea beetles and soil microbial communities of a canola seed treatment containing a neonicotinoid insecticide and fungicides. Crop yields were comparable between intercrops and monocultures of canola and wheat. Crop quality characteristics and flea beetle feeding damage to canola seedlings had variable responses to intercropping. Flea beetle feeding was reduced with the inclusion of the seed treatment by between 1 and 20% damaged leaf area, although only one site‐year had damage levels great enough to overcome plant compensatory abilities in untreated plots. The first true‐leaf stage of canola development experienced the greatest flea beetle damage. Proportions of pathogen‐infected wheat leaf tissue were up to 2.5 times greater in intercrops than wheat monocultures but tended to decrease as the proportion of canola in the intercrops increased. Soil microbial parameters were unaffected by factors investigated. Although intercrop yields approximated those of monocultures, additional benefits of canola–wheat intercrops determined in this study appear insufficient to recommend this system for widespread adoption.

Effect of Crop Rotation on the Soil Pathogen Population Dynamics and Canola Seedling Establishment

Effect of Crop Rotation on the Soil Pathogen Population Dynamics and Canola Seedling Establishment

The presence of a 1-aminocyclopropane-1-carboxylate (ACC) deaminase deletion mutation alters the physiology of the endophytic plant growth-promoting bacteriumBurkholderia phytofirmansPsJN

The structural gene for 1-aminocyclopropane-1-carboxylate (ACC) deaminase (acdS) from the endophytic plant growth-promoting bacterium Burkholderia phytofirmans PsJN was isolated and used to construct a mutant strain B. phytofirmans YS2 (B. phytofirmans PsJN/Delta acdS), in which an internal segment of the acdS gene was deleted. The mutant YS2 lost ACC deaminase activity as well as the ability to promote the elongation of the roots of canola seedlings. Concomitant with the creation of this deletion mutant, a number of physiological changes were observed in the bacterium, including an increase in indole acetic acid synthesis, a decrease in the production of siderophores and an increase in the cellular level of the stationary-phase sigma factor, RpoS. Introduction of the wild-type acdS gene into the mutant YS2 to construct strain B. phytofirmans YS3 (B. phytofirmans YS2/pRK-AcdS) restored both ACC deaminase activity and plant growth-promotion activity in strain YS3. However, the complemented mutant still showed the above-mentioned physiological changes.

Differential sensitivity of canola ( Brassica napus) seedlings to ultraviolet-B radiation, water stress and abscisic acid

Responses of canola ( Brassica napus L.) seedlings to three ultraviolet (UV)-B levels [0 (zero), 5 (ambient) and 10 (enhanced) kJ m −2 d −1], two watering regimes (well-watered and water-stressed), and two abscisic acid (ABA) levels (with and without application) were investigated. Overall, enhanced UVB and water stress negatively affected plant growth and physiology, but ABA had very little effect. Enhanced UVB decreased stem height, leaf area, plant dry matter, water use efficiency and wax content, but increased concentrations of chlorophyll a, carotenoids and flavonoids, and ethylene evolution. Water stress reduced stem height and diameter, leaf area, plant dry matter, leaf weight ratio and shoot:root weight ratio under zero and ambient UVB. Water stress also reduced chlorophyll a and carotenoids in plants exposed to enhanced UVB. ABA with watering regime had significant interactive effects only on leaf dry matter and wax content. We found that enhanced UVB and water stress adversely affected B. napus seedlings. Interaction between these two factors affected plant performance. In this interaction, ABA had little significant role. Also, optimum vegetative growth and biomass were achieved under ambient UVB.

Phyllotreta cruciferae and Phyllotreta striolata responses to insecticidal seed treatments with different modes of action

AbstractThe strategy used most commonly in western North America to protect seedlings of canola (Brassica rapa L. and Brassica napus L.) from attack by adults of the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (Fabricius) (Coleoptera: Chrysomelidae) involves planting seed coated with insecticide for systemic activity. Previous research determined that the two beetle species responded differently to the most commonly used neonicotinoid seed dressings. However, other insecticides that exploit different modes of action have commercial potential for managing infestations of these pests, but no information exists on their efficacies for these flea beetle species. Studies were conducted to compare effects of the neonicotinoid compounds, thiamethoxam and imidacloprid, to spinosyn and fipronil as systemic seed treatments for reducing feeding damage to canola seedlings and increasing mortality of P. cruciferae and P. striolata. Phyllotreta cruciferae experienced greater mortality and caused less feeding damage than P. striolata to seedlings treated with the neonicotinoid compounds. Mortality increased and feeding damage decreased significantly when beetles fed upon seedlings treated with fipronil, indicating its potential usefulness for control of these pests. However, spinosyn seed treatment was relatively ineffective against either beetle species. Higher rates of P. striolata mortality with fipronil than thiamethoxam suggest that fipronil may provide improved flea beetle control over hundreds of thousands of hectares in western North America where flea beetle populations are dominated by P. striolata, and control with thiamethoxam has been suboptimal.

Plant availability of phosphorus from fluid fertiliser is maintained under soil moisture deficit in non-calcareous soils of south-eastern Australia

Low soil moisture and phosphorus (P) deficiencies restrict grain production in south-eastern Australia. The effect of the soil moisture regime on the plant availability of P from fluid mono-ammonium phosphate (MAP) fertiliser was examined during vegetative growth of wheat and canola in P-responsive soils from the Wimmera, Mallee, and high rainfall zone (Glenelg) regions of Victoria. Three plant growth experiments were performed. In Experiment 1, wheat growth and P uptake increased synergistically as soil moisture increased above permanent wilting point (PWP) and as P rate increased. In Experiment 2, the uptake of P from MAP fertiliser of wheat growing under a soil moisture deficit was examined using radioactive (32P) labelling. A factorial design compared uptake from intact soil cores of 3 soil types (Vertosol, Sodosol, Chromosol), 2 depths of fertiliser placement (40 and 80 mm), and either 0 or 25 kg P/ha. Results showed distinct plant responses to both the presence and depth of MAP fertiliser. Banding MAP close to the seed was most efficient in terms of recovery of the fertiliser P, regardless of the soil moisture conditions. Soil moisture regime affected the plant uptake of soil P, rather than fertiliser P, with more soil P taken up by the plants when soil moisture increased. The plant availability of the residual MAP fertiliser in the soil was subsequently examined in Experiment 3. The availability of the residual MAP to canola seedlings was equivalent to 8 kg P/ha of freshly applied MAP. Following both crops (9 months), Colwell P values indicated no further residual MAP availability in soil that had been under the wet regime, and only a small residual value in soil from the dry regime. Banded application of fluid MAP close to the seed and into soil that is above PWP is recommended, even when a relatively dry season is expected, although the residual value to following crops may be limited.

Effects of seeding date and canola species on seedling damage by flea beetles in three ecoregions

AbstractFlea beetles (Phyllotreta striolata (Fabricius), Phyllotreta cruciferae (Goeze) and Psylliodes punctulata Melsheimer) (Coleoptera: Chrysomelidae) are chronic threats to canola seedling establishment throughout the Northern Great Plains of North America. We conducted field studies in AB, Canada, from 2001 to 2004 at Lethbridge, Lacombe and Beaverlodge in the southern, central and northern regions of the province, respectively, to assess the impacts of seeding date (fall, April, May), and canola species (Brassica rapa L., Brassica napus L.) on flea beetle damage to canola. Flea beetle damage was generally low at Lacombe but reached economic threshold levels at other sites. Although our results were not consistent in all years, seeding date had opposite effects on flea beetle damage to canola seedlings at the southern and northern sites. In the south, both canola species planted in April escaped flea beetle damage unlike the May‐seeded plots, which required insecticide spraying in 2003. The numbers of flea beetles on sticky cards sampled during the seedling stage of canola were also lower in early‐planted plots than in those planted in May. In the north, flea beetle damage was lower in the May‐planted plots compared with those planted earlier. To maximize yields, canola growers need to plant as early as possible in all agro‐ecoregions; our study showed that crops in the central and northern regions will be at greater risk of flea beetle damage than in southern regions.

A rapid effect of applied brassinolide on abscisic acid concentrations in Brassica napus leaf tissue subjected to short-term heat stress

Three-week old canola (Brassica napus L.) seedlings grown at 20/16°C (day/night) were subjected to short-term (4 and 8 h) heat stress (45°C) or maintained at a normal temperature of 20°C. Half of the plants under each treatment received a 10−6 M solution of brassinolide (BL) 1 h prior to beginning the temperature treatments. The concentration (ng/g dry weight) of endogenous abscisic acid (ABA) was subsequently determined in young leaves via the stable isotope dilution method. Applied BL had no effect on endogenous ABA for plants maintained at normal temperatures. However, ABA concentration was significantly elevated by heat stress alone and doubled by heat stress + BL. These results suggest that the well-known enhancement of tolerance to high temperature stress that can be obtained by BL or 24-epi-BL applications may be caused by a brassinosteroid-induced elevation in endogenous ABA concentration.

Polymer Seed Coating Effects Winter Canola Seedling Establishment in Different Soil Types

ABSTRACT Increased stand establishment from polymer-coated seed has been reported in some crops, including spring type canola (Brassica napus L.), however, effects of polymers on winter canola have not been evaluated. The objectives of this research were to evaluate effects of three polymers [CelGard (CP), Spectrum 511 (SP), and DiscoClear (DC)], each at three concentrations (0.33%, 0.66%, and 0.99%), alone, with fungicide Helix, and Apron applied to seeds of two winter canola cultivars ‘Jetton’ and ‘Abilene’, which were planted at 1.9 cm and 3.8 cm depth in three soil types (sandy, silt, and clay loam). Treatments were distributed in a randomized complete-block design in each soil. Polymer CelGard application on cv. ‘Abilene’ and DiscoClear on cv. ‘Jetton’ gave highest seedling establishment in all three soil types. Seeds of both the cultivars, when centricoated with Helix, along with polymer coating, gave higher seedling establishment (88.0% in cv. ‘Abilene’ and 85.0% in cv. ‘Jetton’) as compared to oth...

Differences in Phyllotreta cruciferae and Phyllotreta striolata (Coleoptera: Chrysomelidae) Responses to Neonicotinoid Seed Treatments

Insecticidal seed treatments are used commonly throughout the Northern Great Plains of North America to systemically protect seedlings of canola (Brassica napus L. and Brassica rapa L.) from attack by the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae). Here, we investigated differential responses by the two flea beetle species to the neonicotinoid seed treatments thiamethoxam (Helix and Helix XTra) and clothianidin (Prosper 400) in greenhouse experiments. P. cruciferae experienced higher mortality and fed less when exposed to these compounds than did P. striolata. Beetles of the overwintered and the summer generations responded differently when feeding on seedlings that developed with insecticidal seed treatments, with mortality higher for P. cruciferae in May than in August. When the two flea beetle species were held together at equal densities and allowed to feed on seedlings affected by the seed treatments, mortality of P. cruciferae significantly exceeded that of P. striolata. Differences in efficacies of these compounds for these beetles have ramifications for management strategies in regions where these insects occur sympatrically. Competitive release of P. striolata was previously reported to occur when P. cruciferae was excluded from brassicaceous crops; consequently, the consistent use of these seed treatments over millions of hectares of canola cropland may be a factor that contributes to a shift in prevalence of flea beetle pest species from P. cruciferae toward P. striolata.

Differences in <I>Phyllotreta cruciferae</I> and <I>Phyllotreta striolata</I> (Coleoptera: Chrysomelidae) Responses to Neonicotinoid Seed Treatments

Insecticidal seed treatments are used commonly throughout the Northern Great Plains of North America to systemically protect seedlings of canola (Brassica napus L. and Brassica rapa L.) from attack by the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae). Here, we investigated differential responses by the two flea beetle species to the neonicotinoid seed treatments thiamethoxam (Helix and Helix XTra) and clothianidin (Prosper 400) in greenhouse experiments. P. cruciferae experienced higher mortality and fed less when exposed to these compounds than did P. striolata. Beetles of the overwintered and the summer generations responded differently when feeding on seedlings that developed with insecticidal seed treatments, with mortality higher for P. cruciferae in May than in August. When the two flea beetle species were held together at equal densities and allowed to feed on seedlings affected by the seed treatments, mortality of P. cruciferae significantly exceeded that of P. striolata. Differences in efficacies of these compounds for these beetles have ramifications for management strategies in regions where these insects occur sympatrically. Competitive release of P. striolata was previously reported to occur when P. cruciferae was excluded from brassicaceous crops; consequently, the consistent use of these seed treatments over millions of hectares of canola cropland may be a factor that contributes to a shift in prevalence of flea beetle pest species from P. cruciferae toward P. striolata.

A novel role for Trichoderma secondary metabolites in the interactions with plants

Secondary metabolites play a pivotal role in the antagonistic activities of some biocontrol species of Trichoderma resulting in the suppression of plant pathogens, but their involvement in complex interactions with plants has not been specifically studied. In this work the major secondary metabolites produced by biocontrol strains of Trichoderma ( T. harzianum strains T22, T39 and A6, and T. atroviride strain P1) have been investigated for their effect on plant growth promotion. An auxin-like activity was observed on etiolated pea ( Pisum sativum) stems treated with harzianolide and 6- n-pentyl-6 H-pyran-2-one (6PP), which also affected the growth of tomato ( Lycopersicum esculentum) and canola ( Brassica napus) seedlings. The ability of these molecules to induce systemic defence responses in planta was also investigated. Tomato and oil-seed rape seedlings were treated with the metabolites and then inoculated with a spore suspension of Botrytis cinerea or Leptosphaeria maculans, respectively. In both cases, a reduction of disease symptoms was observed, particularly on 6PP-treated plants. Moreover an over-expression of pathogenesis-related (PR) proteins was also detected in treated plants. These results clearly indicate that secondary metabolites of Trichoderma spp. may have a role in both plant growth regulation and activation of plant defence responses.

Effects of seed size and seed weight on seedling establishment, vigour and tolerance of Argentine canola (Brassica napus) to flea beetles, Phyllotreta spp.

A 3-yr study was conducted on four Brassica napus L. cultivars to determine the effects of seed size and seed weight on the performance and tolerance of canola seedlings to feeding damage by flea beetles, Phyllotreta spp. (Coleoptera: Chrysom elidae). Seed lots of a doubled haploid cultivar Cyclone, hybrid cultivar AC H102 and two open-pollinated cultivars Profit and AC Elect were sieved to obtain small, medium, large and very large seeds (1.4–1.6, 1.6–1.8, 1.8–2.0 and 2.0–2.2 mm diameter, respectively). Under controlled environmental conditions, leaf area, shoot weight and biomass of seedlings from large and very large seeds were 1.3–2.0 times greater than those of seedlings from small seeds. Under field conditions without insecticides, seedlings from small seeds of each cultivar had the highest flea beetle damage, poorest establishment, and lowest shoot weight, biomass and yield. Compared with small seeds, large seeds improved seedling establishment, shoot weight, biomass and yield by 1.1, 1.6–2.0, 3.0–3.5 and 1.5 times, respectively. Results indicated that seedlings from large seeds are more vigorous and tolerant to flea beetle damage than seedlings from medium or small seeds. Seedling vigour and tolerance was due to a higher initial shoot biomass and higher growth rate when flea beetle damage was severe. When damage exceeded 50%, large heavy seeds had the best stand establishment, best shoot growth and highest yield in each cultivar. Key words: Canola, flea beetles, seed size, seed weight, seedling vigour, tolerance

The effects of NaCl priming on salt tolerance in canola (Brassica napus) seedlings grown under saline conditions

The effects of NaCl priming on salt tolerance in canola (Brassica napus) seedlings grown under saline conditions

Improvement of Brassica napus growth under cadmium stress by cadmium-resistant rhizobacteria

This study focuses on the characterization of four bacterial isolates from heavy metal-polluted rhizosphere in order to examine their plant growth promoting (PGP) activity. The PGP activity on the canola ( Brassica napus) of the strains which showed cadmium resistance and multiple PGP traits was assessed in the presence and in the absence of Cd 2+. The strains, Pseudomonas tolaasii ACC23, Pseudomonas fluorescens ACC9, Alcaligenes sp. ZN4 and Mycobacterium sp. ACC14 showed 1-aminocyclopropane-1-carboxylate deaminase (ACCD) activity. They also synthesized ACCD enzyme in vitro when 0.4 mM Cd 2+ was added to the growth medium. The presence of the metal, however, reduced the ACCD activity in Alcaligenes sp. ZN4 and Mycobacterium sp. ACC14, while it did not affect the ACCD activity of P. tolaasii ACC23 and P. fluorescens ACC9. ACC9 and ACC23 produced indole acetic acid (IAA) and siderophores, while ACC14 produced only IAA. IAA and siderophores were produced more actively under Cd-stress. Root elongation assays conducted on B. napus under gnotobiotic conditions demonstrated increases (from 34% up to 97%) in root elongation of inoculated canola seedlings compared to the control plants. Subsequently, the effect of inoculation with these strains on growth and uptake of Cd 2+ in roots and shoots of canola was studied in pot experiments using Cd-free and Cd-treated (15 μg Cd 2+ g −1 dw) soil. Inoculation with P. tolaasii ACC23, P. fluorescens ACC9 and Mycobacterium sp. ACC14 promoted the growth of plants at concentrations of 0 and 15 μg Cd 2+ g −1 soil. The maximum growth was observed in the plants inoculated with P. tolaasii ACC23. The strains did not influence the specific accumulation of cadmium in the root and shoot systems, but all increased the plant biomass and consequently the total cadmium accumulation. The present observations showed that the bacterial strains used in this study protect the plants against the inhibitory effects of cadmium, probably due to the production of IAA, siderophores and ACCD activity.

Epidemiology of Blackleg (Leptosphaeria maculans) of Canola (Brassica napus) in Relation to Maturation of Pseudothecia and Discharge of Ascospores in Western Australia

ABSTRACT The timing of maturation of pseudothecia and discharge of ascospores of the blackleg fungus (Leptosphaeria maculans) is critical in relation to infection early in the cropping season of canola. During 1998 to 2000, development of pseudothecia was investigated on residues of the previous year's canola crop collected from four agroclimatically different locations: Mount Barker (southern high rainfall), Wongan Hills (central medium rainfall), Merredin (central low rainfall), and East Chapman (northern low rainfall) in Western Australia. The pseudothecia matured on residues at different times after harvest in various regions. In general, pseudothecia maturity occurred earlier in the high-rainfall areas than in medium- and low-rainfall areas. An ascospore discharge pattern was investigated from residues of crop from the previous year (6-month-old residues) at three locations-Mount Barker, Wongan Hills, and East Chapman in Western Australia-and from 18-month-old residues that were burnt and raked in the previous year at Mount Barker and East Chapman. Ascospore discharge commenced earlier in high-rainfall (>450 mm) areas (Mount Barker) and late in northern low-rainfall (<325 mm) areas (East Chapman). The major ascospore showers took place during May (late autumn) and June (early winter) at Mount Barker and during July and August (mid- to late winter) at East Chapman. The number of ascospores discharged was extremely low at East Chapman compared with Mount Barker. At both locations, the number of ascospores discharged from 18-month-old residues that were raked and burnt in the previous year were only approximately 10% of those discharged from previous year's residues left undisturbed. The discharge of ascospores on any given day was negatively correlated with accumulated temperatures, maximum temperature, evaporation, minimum and maximum soil temperatures, and solar radiation and was positively correlated with the minimum temperature, rain, and minimum relative humidity. This is the first report describing how pseudothecia mature on residues in different rainfall areas in Western Australia, and it potentially can be used in developing a forecasting system to avoid the synchronization of major ascospore showers with the maximum susceptibility period of canola seedlings.

Laboratory studies of the toxicity of spinosad and deltamethrin to Phyllotreta cruciferae (Coleoptera: Chrysomelidae)

AbstractLaboratory experiments were conducted to evaluate the contact and oral toxicity of commercial formulations of spinosad and deltamethrin to adults of the crucifer flea beetle, Phyllotreta cruciferae (Goeze). Method of exposure had a significant effect on flea beetle mortality and feeding damage to canola seedlings. Topical treatment of flea beetles with deltamethrin or different concentrations of spinosad resulted in significantly lower mortality and higher feeding damage than exposure to treated canola cotyledons. Results indicated that spinosad was more toxic by ingestion than by topical contact. Mortality from treated cotyledons was significantly higher with 60 ppm deltamethrin than with 80 or 120 ppm spinosad after 24 h exposure but not after 120 h exposure. Delayed mortality in the spinosad treatments did not result in high feeding damage; damage after 120 h was not significantly different in the spinosad and deltamethrin treatments. Low concentrations of spinosad (40 ppm) strongly inhibited feeding activity within 24 h after exposure. Mortality from spinosad was higher after beetles were exposed to treated cotyledons for 120 h than for 24 h. Mortality from spinosad, but not deltamethrin, was significantly higher at 25 °C than at 15 °C. An ionic surfactant, polyethylenimine, increased the toxicity of 40 ppm spinosad. Our study suggests that spinosad has potential for use as an insecticide against crucifer flea beetles on canola.

Slug control in Australian canola: monitoring, molluscicidal baits and economic thresholds

Exotic slugs have become serious pests of canola, at establishment, in Southern Australian high-rainfall cropping zones. Slugs were monitored using relatively inexpensive 300 mm x 300 mm terracotta tiles acting as refuges. An investigation was made of the effects of the time of application of chelated iron baits on the slug species Deroceras reticulatum Müller and Lehmannia nyctelia Bourguignat. Baits reduced the number of surface-active slug species. A single application at sowing provided greater efficacy than one application before sowing, and efficacy was comparable with that of two applications. Canola seedling densities showed a negative response to D. reticulatum numbers; the presence of even one individual per refuge trap reduced seedling numbers below optimum densities. Thistles and other vegetation were associated with increased numbers of slugs. European guidelines for slug monitoring and damage appear to be at least partly applicable to Australian conditions.

Sublethal effects of imidacloprid and pymetrozine on population growth parameters of cabbage aphid,Brevicoryne brassicaeon rapeseed,Brassica napusL.

AbstractEfficiency of imidacloprid and pymetrozine on population growth parameters of cabbage aphid,Brevicoryne brassicaeL. (Homoptera: Aphididae) was determined using demographic toxicology by leaf dip method. At first, bioassay tests were performed. The LC50value and confidence limit for imidacloprid and pymetrozine were 1.61 × 10−5mol/L (0.74 × 10−5–2.66 × 10−5) and 2.14 × 10−4mol/L (1.24 × 10−4–3.40 × 10−4), respectively. To evaluate the sublethal effect of two insecticides on population growth parameters of cabbage aphid, LC30concentrations of imidacloprid and pymetrozine were used at 5 mol/L and 30 mol/L. The experiments were carried out in a incubator at 20 ± 1°C, 60%± 5% RH and 16: 8 (L: D) photoperiod on canola seedlings,Brassica napusL. var. ‘PF’. Net fecundity rate decreased in both insecticide‐treated populations. Intrinsic rates of increase (rm) were lower in imidacloprid and pymetrozine treatments than in controls. Intrinsic birth rates also decreased in treated populations. There was a relative increase in intrinsic death rates of treated populations. The mean generation times and doubling time were also lower in populations treated with insecticides than in controls. There was a considerable reduction in the average numbers of nymphs reproduced per female as compared with the control. The average longevity of female adults in the control was significantly different from those treated with imidacloprid and pymetrozine. However, there was no significant differences in aphid life‐table parameters between the two insecticide‐treated populations (P&gt; 0.01).

Comparative Evaluation and Economic Potential of Ecorational Versus Chemical Insecticides for Crucifer Flea Beetle (Coleoptera: Chrysomelidae) Management in Canola

From 2001 to 2004, field studies were conducted to evaluate the effect of the ecorational insecticides SpinTor (spinosad), BotaniGard (Beauveria bassiana), Neemix (azadirachtin), and Surround (kaolin) against crucifer flea beetle on canola, Brassica napus L., at the cotyledon stage. The ecorational treatments were compared with a standard foliar chemical insecticide, Capture (bifenthrin), and the chemical seed treatment insecticide Helix XTra (thiamethoxam). This study indicated that flea beetle injury was lower for Helix XTra, Capture, and the ecorational insecticide SpinTor. SpinTor was less effective when flea beetle populations were relatively high (200-300 per trap-week). Yields for chemical insecticide treatments were always greater than SpinTor, with differences being the smallest (68-374 kg/ha) at low levels of flea beetle feeding injury. Differences were greatest when canola seedling injury was high (775-1,364 kg/ha). Yield differences between the conventional insecticides and BotaniGard, Neemix, and Surround were 119-439 and 61-2,248 kg/ha at low and high flea beetle feeding injury, respectively. Although yield differences between SpinTor and chemical insecticides were relatively small at lower levels of flea beetle injury, net losses ranged from $47 to $151/ha when SpinTor was used as an alternative to a standard chemical seed treatment, Helix XTra. This suggests that SpinTor would not be a viable alternative to the chemical insecticide. Net losses ranged from $30 to $266/ha when BotaniGard, Neemix, and Surround were used as alternatives to the seed treatment.