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2013 Bertha Armyworm Forecast

 
 
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Bertha armyworm (Mamestra configurata) was monitored in 2012 using a network of pheromone-baited traps placed in 196 locations throughout Alberta. Pheromone traps are used to determine the density and distribution of moths. This network of pheromone traps is organized by AARD and individual traps are managed by a wide range of cooperators. Without dedicated and willing cooperators such a comprehensive monitoring system would not be possible. In the past couple years we have developed the ability for cooperators to send data using their smart phones which has been a popular application (this is a web based function). Overall numbers of BAW moths climbed into warning levels in 50 of the 196 trap locations (mostly in central Alberta). There remains a very real potential for BAW problems again in 2013. The 2013 bertha armyworm survey will be very important in determining the level of risk. The 2013 bertha armyworm survey results will be online in mid June when the new survey season starts. Cumulative moth counts in traps during June and July of 2012 will give us a much better evaluation of the population and therefore the risk in August.

Bertha armyworm populations are normally kept in check by such factors as weather and natural enemies. Generally parasitism rates of 50 - 60 percent in bertha larval populations have indicated the end of a local outbreak in the following year. The results from 2012 properly predicted an outbreak in central Alberta that may continue into 2013.
Potential damage from bertha armyworm may be more or less severe than suggested by the moth count data depending on weather and crop conditions and localized population dynamics. An insecticide application is recommended when the larval numbers meet the economic threshold . For pesticide options visit Alberta Agriculture's Pesticide Selector.


Life cycle information
Diagnostic guide
How to assemble a bertha armyworm trap
Video on how to assemble a bertha armyworm trap

The bertha armyworm forecasting program for Alberta has been conducted since 1995. Provincial government personnel, industry agronomists, Applied Research Associations, Agricultural Fieldmen and cooperating growers maintain the pheromone trap network. The cumulative moth count maps are maintained by Alberta Agriculture and Rural Development.

During the monitoring season and until January the map is a Google map which means you can move around, zoom in and click on the individual balloons. By clicking on a balloon it will show the organization that looked after that trap, what municipality the trap is in, the weekly count and cumulative count (all counts displayed are the average between the two traps at a site). During the trapping season the information is updated as the entries are made into the data collection website. The resolution is not accurate enough to pinpoint the exact location of individual traps.

The objective of the monitoring is to heighten the awareness of canola producers to the damage potential of bertha armyworm. Forecast maps DO NOT replace field scouting. No field should be treated for bertha armyworm control without proper field scouting. Moth catches indicate the potential for damage but the actual populations must be assessed. Experience from 2012 has shown us that adjacent fields or even different parts of the same field can have greatly different bertha armyworm numbers.

Cumulative moth catch Risk LevelInterpretation
0 to 300LowInfestations are unlikely to be widespread, but fields should be inspected for signs of insects or damage.
300 to 900UncertainInfestations may not be widespread, but fields that were particularly attractive to egg-laying females could be infested. Check your fields.
900 to 1200ModerateInfestations likely, canola fields should be sampled regularly for larvae and for evidence of damage.
1200+High Infestations very likely, canola fields should be sampled frequently for larvae and for evidence of damage.

Alberta Insect Pest Monitoring Network 2012 Annual Report

For more information on this insect and its management contact the Ag-Info Centre at 310-FARM (3276) or bugs.r.us@gov.ab.ca
 
 
 
 
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For more information about the content of this document, contact Scott Meers.
This document is maintained by Shelley Barkley.
This information published to the web on January 14, 2013.
Last Reviewed/Revised on June 26, 2013.