Bertha armyworm
Bertha armyworm is one of the most economically significant pests of canola, and infestations can cause significant damage when populations are high.
Provincial monitoring programs can give you an early warning that bertha armyworm populations are present in your area and could be a threat to your canola. The monitoring programs rely on a network of pheromone traps that catch adult male moths who are in fields looking for mates.
Begin scouting for bertha armyworm after peak flowering. Start watching provincial scouting programs starting in June, although you need to scout your own fields too because pressure can change from field to field.
Move quickly to identify the cause of early defoliation in canola. Defoliation can be a sign that bertha armyworms are feeding. Bertha armyworm requires control if they are past the size of a full-size diamondback moth larvae, at least ½ inch long. The two insects can be hard to tell apart. Consult the Canola Council of Canada’s economic threshold chart to determine if you need to spray and for help identifying bertha armyworm.
Choose an appropriate rate of Coragen® MaX insecticide based on the situation. If worms are smaller than an inch and numbers are low, the 120 ac/2L jug is the appropriate rate. With larger worms and higher populations, the 60-40 ac/2L jug rates should be considered.
Coragen® MaX insecticide delivers fast-acting and extended control of bertha armyworm with minimal impact on many important pollinators and beneficials*. The population ratio of natural enemies to bertha armyworm takes time to catch up when there is an outbreak. The combination of natural predators consuming bertha armyworm along with the extended control of Coragen® MaX insecticide will provide strong protection of your canola crop.
Diamondback moth
Diamondback moths are another annual occurrence on the Prairies but the severity of infestations can be hard to predict. The insect doesn’t overwinter in Canada and is blown in each year from the southern and western United States and Mexico.
Since diamondback moths arrive on wind currents, Prairie entomologists use wind trajectories to predict when the insect is likely to reach Western Canada. Pheromone traps help confirm the arrival of diamondback moth. There can be up to four generations of moths in a year.1
It’s important to keep scouting all season long, especially when the pest-monitoring warning bells go off that moths have arrived from down south. Remove plants in an area measuring one square foot. Shake the plants onto a clean surface and count the number of dislodged larvae. Refer to sites such as the Canola Council of Canada’s Canola Encyclopedia (www.canolaencyclopedia.ca) for more information on economic thresholds.
Diamondback moths are most active at night but that doesn’t mean you have to be. Since Coragen® MaX insecticide has residual properties and it controls upon ingestion, you have the freedom to spray during the day. Coragen® MaX insecticide delivers extended control** of diamondback moths and other insect pests. It can also be sprayed during hot days or cool nights, giving you maximum flexibility on when to spray. Note, to ensure maximum safety to beneficials and pollinators, applications should be made outside of peak foraging times (i.e. morning or evenings).
Grasshoppers
Grasshoppers overwinter in the soil as eggs and emerge as nymphs in late May when the soil warms. There are over 180 different species of grasshopper but only four cause significant economic damage to crops in Western Canada.
Grasshoppers go through only one generation each year on the Prairies. Some species will feed on a range of plants, sometimes voraciously. Both nymphs and adult grasshoppers cause economic damage to crops.
Entomologists use growing degree days and fall grasshopper surveys to help predict when and where grasshopper pressure will be greatest. Watch the Prairie Pest Monitoring Network (www.prairiepest.ca) to monitor grasshopper egg hatching as the season evolves.
Grasshopper pressure can be different from field to field. Unfortunately, they’re difficult to scout as they jump away with each step you take in a field. Instead, look for feeding damage and identify the species of grasshopper you’re seeing. The grasshopper entry in the Canola Council of Canada’s Canola Encyclopedia has detailed instructions on how to scout for grasshopper.
Spray an insecticide when grasshoppers meet the economic threshold. Coragen® MaX insecticide is the latest highly concentrated formulation of Coragen® insecticide. The highly concentrated formulation comes in a 2L jug that treats 60 to 120 acres at the most common application rates, making handling, transport and storage easier.
Grasshoppers need to consume the plant after the application of Coragen® MaX insecticide. Upon ingestion of the active, the grasshopper ultimately dies due to starvation because the chewing mouthparts are paralyzed.
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*When applied at label rates. In line with integrated pest management and good agricultural practices, insecticide applications should be made when pollinators are not foraging to avoid unnecessary exposure.
**Depending on rate and when weather and temperature are optimal.
1 https://www.canolacouncil.org/research-blog/investigating-diamondback-moth-population-factors/