Flea beetles are a standard insect pest in early rising canola throughout the Prairies. There are two essential species of concern for canola (and mustard) growers: the striped flea beetle and the crucifer flea beetle.
“The feeding is indistinguishable, but the striped flea beetle comes up earlier,” says James Tansey, provincial entomologist with Saskatchewan Ministry of Agriculture. On this episode of the Canola College, Tansey says that within the Saskatoon space, the striped flea beetle is already up and lively, in accordance to some stories.
Northern areas are dominated by striped flea beetles and their vary is increasing, says Tansey — they like cooler, moist situations. Crucifer flea beetles are nonetheless dominant within the southern a part of the province. The completely different distribution has to do with their overwintering durations.
“There are some who feel that striped flea beetle can cause a little bit more damage, and there’s also some anecdotal evidence that they tend to hunker down when things are cool and wet and can feed on the stems, which can cause a fair bit of damage,” says Tansey.
For financial thresholds, 50 per cent defoliation of cotyledons and first true leaves is the purpose at which yield will decline. Nonetheless, the motion threshold, is 25 per cent, with the situation that flea beetles are nonetheless current and feeding. Tansey provides that one of many options of seed therapies that defend in opposition to flea beetles is that they’re systemic — the flea beetle has to ingest it earlier than it’ll work.
When you’re scouting, be sure that it isn’t simply injury you see, but in addition lively flea beetles, says Tansey, as a result of generally a excessive inhabitants can utterly overwhelm a crop.
Populations will also be very localized, so it’s essential to scout a number of areas in a discipline, and to look for that motion threshold of 25 per cent injury to the leaves. The extra crops and areas that you just scout, the higher thought you’ll have of what actions you want to take, and you may catch a state of affairs earlier than it will get uncontrolled. Tansey additionally notes that flea beetles will transfer from the perimeters of fields inwards.
Within the video, Tansey talks about seed deal with and in-crop management choices: