Usually a pest of canola, however typically a pest of faba bean and different pulses, the bertha armyworm is a big eater of crop yield in Canada.
For this episode of the Pest and Predator podcast, dropped at you by Field Heroes powered by the Western Grains Research Foundation, host Shaun Haney discusses a captivating predator of bertha armyworm with Alberta Pulse Growers’s Nevin Rosaasen.
The bertha’s most frequent predator, Banchus flavescens, is straightforward to differentiate by its distinctive segmented physique and a really lengthy ovipositor that appears like an extended tail. It is often a light-weight yellow, however it could actually come in different colors as properly, with shades of orange on the “tail.”
This parasitoid wasp lays its eggs in the primary to 3rd larvae stage of a bertha armyworms. The mature larvae are then killed previous to getting into the soil to pupate overwinter, so this pure enemy doesn’t destroy the larvae previous to the crop harm occurring, nonetheless, it retains the bertha populations in test. Rosaasen explains this wasp is likely one of the motive we regularly we see bertha armyworm impacts restricted to 2 to a few years at most. (learn extra beneath the podcast)
Rosaasen says that figuring out a dynamic threshold for bertha armyworm — one which accounts for useful insect populations — is a piece in progress. “We haven’t established dynamic thresholds as a result of it will require a PhD challenge and years of research, however we’re shifting in the direction of saying that in case you see this parasitoid insect current that it is best to restrict spraying,” he says. Too typically, an insecticide spray is likely to be financial in the quick time period, however detrimental in the long run to useful insect populations.
“There’s nothing like boots on the bottom,” Rosaasen says in regards to totally scouting for each pests and predators. Maps, like these from the Prairie Pest Monitoring Network, are useful and a very good device for constructing pest populations, however figuring out and quantifying useful bugs in the sector requires in-person scouting. can