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The crucifer flea beetle, Phyllotreta cruciferae (Goeze), is a key pest of canola (Brassica napus L.) in the northern Great Plains of North America. The efficacies of entomopathogenic nematodes (Steinernema spp. and Heterorhabditis spp.), a sprayable polymer gel, and a combination of both were assessed on canola for flea beetle management. Plots were treated soon after colonization by adult flea beetles, when canola was in the cotyledon to one-leaf stage. Ten plants along a 3.6-m section of row were selected and rated at pre-treatment and 7 and 14 d post treatment using the damage-rating scheme advanced by the European Plant Protection Organization, where 1=0%, 2=2%, 3=5%, 4=10%, and 5=25% leaf area injury. Under moderate flea beetle feeding pressure (1-3.3% leaf area damaged), seeds treated with Gaucho 600 (Bayer CropScience LP Raleigh, NC) (imidacloprid) produced the highest yield (843.2 kg/ha). Meanwhile, Barricade (Barricade International, Inc. Hobe Sound, FL) (polymer gel; 1%) + Scanmask (BioLogic Company Inc, Willow Hill, PA) (Steinernema feltiae) resulted in the highest yields: 1020.8 kg/ha under high (2.0-5.3% leaf area damaged), and 670.2 kg/ha at extremely high (4.3-8.6 % leaf area damaged) feeding pressure. Our results suggest that Barricade (1%) + Scanmask (S. feltiae) can serve as an alternative to the conventional chemical seed treatment. Moreover, Scanmask (S. feltiae) can be used to complement the effects of seed treatment after its protection has run out. [ABSTRACT FROM AUTHOR]

The crucifer flea beetle, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae), has recently emerged as a serious pest of canola ( Brassica napus L.) in Montana. The adult beetles feed on canola leaves, causing many small holes that stunt growth and reduce yield. In 2013, damage to canola seedlings was high (≈80%) in many parts of Montana, evidence that when flea beetles emerge in large numbers, they can quickly destroy a young canola crop. In the current study, the effectiveness of several biopesticides was evaluated and compared with two insecticides (deltamethrin and bifenthrin) commonly used as foliar sprays as well as seed treatment with an imidacloprid insecticide for the control of P. cruciferae under field conditions in 2013. The biopesticides used included an entomopathogenic nematode ( Steinernema carpocapsae), two entomopathogenic fungi ( Beauveria bassiana and Metarhizium brunneum), neem, and petroleum spray oils. The control agents were delivered in combination or alone in a single or repeated applications at different times. The plant-derived compound neem (azadirachtin), petroleum spray oil, and fatty acids (M-Pede) only showed moderate effect, although they significantly reduced leaf injuries caused by P. cruciferae and resulted in higher canola yield than the untreated control. Combined use of B. bassiana and M. brunneum in two repeated applications and bifenthrin in five applications were most effective in reducing feeding injuries and improving yield levels at both trial locations. This indicates that entomopathogenic fungi are effective against P. cruciferae, and may serve as alternatives to conventional insecticides or seed treatments in managing this pest. [ABSTRACT FROM AUTHOR]

The flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae: Alticinae) are significant pests of crops in the Brassicaceae family. From 2001 to 2003, the efficacy of both new and commonly used treatments for the control of flea beetles in brassicas, Brassica rapa L., were evaluated in three small plot, randomized complete block design trials. Row cover and carbaryl (applied as a weekly foliar spray) were found to be the most consistent at reducing damage in comparison with untreated controls in all trials. Two new products that may provide adequate flea beetle control are spinosad (in either conventional or organic formulations) and thiamethoxam. The plant-derived compounds azidiractin and pyrethrin did not protect treated plants from flea beetle feeding. Treatment of plants with kaolin, or removal of the beetles with a vacuum, also did not reduce the level of crop damage. The level of damage at harvest was found to be correlated with population size of flea beetles in each plot, as measured by captures on yellow sticky traps and direct visual counts. Removal of the outer two leaves of individual B. rapa plants reduced the total number of holes per plant by 40%, while only removing 15% of the leaf area. [ABSTRACT FROM AUTHOR]