SARDA Ag Research News
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Managing Flea Beetles
By Shelleen Gerbig, BSA, P.Ag, SARDA Ag Research and Dr. Maria Angelica Ouellette, Ph.D., NPARA
dult Flea Beetles (Phyllotetra spp.) feed on the cotyledons of newly emerged canola seedlings and cause significant damage to the crop, sometimes requiring costly reseeding operations. Rapidly growing canola seedlings may outgrow the pests as older plants can withstand the feeding pressures. Seed-coated insecticides are the first level of control and often the best, but they require the beetle to feed on the plant to take effect. Large populations of the beetle may damage the crop even if the seed-coated insecticide is effective. If seeding occurs in cold, wet soil and germination is delayed, seedling canola plants may be adversely affected by flea beetles. Seed-applied insecticides are only effective for 2-3 weeks after seeding. Foliar applied insecticides are available, but the time to effectively spray is compressed. Foliar-applied insecticides also have a greater risk of affecting non-target native pollinators such as birds and bees. Relying only on chemical means to control flea beetles could cause problems in the future as the pests may develop resistance to the chemicals, and beneficial insects (flea beetle enemies)
are destroyed. Therefore, it is imperative to combine cultural control methods to reduce the need for chemical insecticide applications. In 2020, SARDA Ag Research, MARA (Makenzie Applied Research Association), and NPARA (North Peace Applied Research Association) started a joint project to evaluate the effectiveness of various cultural methods of control for flea beetles. Increased seeding rate (Dosdall et al. 1999), late seeding date (mid-May to early June) (Cárcamo et al. 2008) and larger seed size (Elliot et al. 2008; Bodnaryk and Lamb 1991) have been some of the agronomic methods used to reduce flea beetle populations. Our trials will also look at the species of flea beetles that affect our crops in the Peace Region. We have three common species; one native species, the crucifer flea beetle and the striped flea beetle. The striped flea beetle is likely the most common in the Peace Region, but it holds the dubious distinction of being the most difficult to control. 13
