| Crop | Soybean |
|---|---|
| Start Date | 2012 |
| End Date | 2014 |
| Principal Investigator | Costamagna, Alejandro , University of Manitoba |
| MPSG Financial Support | $36,950 |
| Total Project Funding | $80,000 |
| Report | Soybean-Aphid-Control-by-Natural-Enemies |
Research Objectives
- Assessment of effective natural enemies of soybean aphid in Manitoba.
- Determination of sources of effective natural enemies of soybean aphid.
- Assessment of the dispersal of effective natural enemies into soybean fields and their control on soybean aphid.
Project Description
Soybean aphids cause major yield losses in soybean in North America. In Manitoba there were widespread soybean aphid population outbreaks during 2006 and 2008, and less severe populations in 2010 and 2011. Natural enemies have been demonstrated to control soybean aphids very effectively in North America, with millions of dollars saved in insecticide applications in the Midwest USA alone. Previous studies have identified natural vegetation and alfalfa crops as potential sources of natural enemies, but there is no information on how far natural enemies disperse from those sources. This project will study the natural enemies of soybean aphids in Manitoba, establish what their sources are, how far they disperse from them, and how effective they are controlling soybean aphids. This information will allow growers to determine what levels of natural control of aphids they have in their fields and avoid unnecessary insecticide applications, preserving and increasing benefits of biological control by natural enemies.
Studies were conducted in commercial soybean crops from 2012 to 2014. In 2014, environmental conditions were conducive to aphid outbreak populations, resulting in three fields developing aphid populations above the economic threshold when predators were excluded from the experimental plants for two weeks; none of the aphid populations exposed to naturally occurring predators were above economic thresholds suggesting that predators naturally occurring in Manitoba can provide strong suppression of soybean aphids, confirming similar findings observed during 2012 and 2013. In 2013, seven-spotted ladybeetles were released in two neighboring fields of soybean and alfalfa to study ladybeetle movement between crops. It was concluded that ladybeetles are efficient at tracking aphids in different crops and that suggests that alfalfa may act as a good source of natural enemies when the soybean fields are infested. During 2013 and 2014, natural enemy movement between soybean and neighboring fields was monitored using bi-directional Malaise located in the border between contiguous fields. Border fields included canola, alfalfa, natural vegetation, wheat, and other habitats. Data from 2013 suggest significant movement of ladybeetles, and brown and green lacewings from natural vegetation to soybean. Samples from 2014 are currently being sorted.