Tuesday, 14 August 2018

Flea beetles (Aug 16, 2018; Wk 15)

Flea Beetles (Chrysomelidae: Phyllotreta species) – By early pod stages in canola, newly eclosed adult flea beetles begin to emerge from the soil.  These individuals typically feed then move away from canola fields to locate overwintering habitats.  

Normally, it can be difficult to locate these newly emerged adults but every few years they are easily observed among canola pods.  These adults can feed on upper leaves and nip at the exterior of canola pods but are typically observed in low densities - too low to cause economic damage.  Even so, be watchful - areas with high numbers of flea beetles late in the growing season are worthwhile to scout early in 2019.  

Remember - the Action Threshold for flea beetles on canola is 25% of COTYLEDON LEAF AREA consumed.  

Normally, it is NOT recommended to apply foliar insecticides for flea beetles in canola during the pod stages for the following reasons:
  • Flea beetles are very mobile at this point in the season,
  • Canola canopy is very thick,
  • Growers must be cautious about pre-harvest intervals,
  • PLUS, little is understood about overwintering survival of this pest!

Reminder - Earlier this season, the Insect of the Week featured flea beetles!

Refer to the flea beetle page from the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.