A weekly report prepared by the staff of the Ministry of Agriculture, Food and Rural Affairs (OMAFRA). If you require further information, regarding this report, call the Elora Resource Centre at 519-846-0941. Office hours: 8:30am to 4:30pm. For technical information, call the Agricultural Information Contact Centre at 1-877-424-1300 or visit the OMAFRA website: www.ontario.ca/omafra.
SCOUTING FOR SOIL INSECT PESTS IN FIELD CROPS
Insecticide seed treatments have proven to provide effective and efficient protection for soil insects in field crops. As the level of adoption of this technology has increased, there has been a shift from the prescriptive use of insecticide seed treatments to a more prophylactic use.
The broader use of insecticide seed treatments increases the risk of exposure to non-target organisms.
This shift in approach to the use of insecticide seed treatments increases the need to re-establish an Integrated Pest Management (IPM) approach in field crops, where insecticide seed treatments are targeted for use only in those fields deemed at risk of soil insect pest infestations.
IPM is an approach to pest management that integrates all available practices and technologies to keep pest populations below threshold in an economically viable way while minimizing the impact to the environment.
Some of the first steps to IPM are to better understand each pest, their life cycle and impact to the crop as well as scouting to assess the risk of these pests so that preventative and cultural measures can be timed appropriately.
Factors that increase risk
Certain factors put some fields more at risk of soil insect pests than others. These factors include soil type, crop history/rotation and pre-plant weed and nutrient management practices.
For example, wireworms are strongly attracted and survive best in fields with sandy or silty soil types that have a frequent grass crop rotation (cereals, mixed forages, grassy weeds), or follow canola or vegetable crops including carrots, sugar beets and potatoes.
Fields planted after newly broken sod or pasture in the last two years are also at high risk. Fields that do not fit these conditions are less likely to be at risk.
Similarly, certain conditions place fields at risk of other insect pests including grubs, seedcorn maggot, black cutworm and others. Fields that do not fit these conditions are less likely at risk and do not need an insecticide seed treatment for protection each year.
Scouting for confirmation
Scouting is always the best method to determine if fields are actually at risk. Fall scouting can predict spring infestations of both wireworms and grubs since the same population present in the soil in the fall will also be present in the spring.
This is a recommended practice even for those growers with a known history of wireworm and grub infestations.
Neonicotinoid seed treatments do not control wireworms or grubs but intoxicate the larvae once they have taken a bite of the treated seed or seedling, causing them to stop feeding long enough for the seedling to get established.
The insecticide does not reduce the pest populations and may require the use of the high rate of insecticide if conditions are ideal for pest populations to increase that year.
Additional cultural methods like tillage or adjusting planting times may also be required to help reduce the risk of crop injury if pest populations are high.
Spring time assessments help determine what impact winter and early spring conditions have had on the early season pests.
Harsh winters can have a large impact on bean leaf beetles for example, while grubs are well protected from extreme temperature fluctuations by hibernating below the frost line.
Spring scouting is also the best time to monitor for those pests that overwinter in the U.S. and migrate here in early spring (eg. black cutworm). Scouting prior to planting informs growers of field conditions that have increased their risk to pests.
Some additional cultural control measures could be implemented or decisions made as to where to best target the insecticide seed treatments. Fields found to be at low risk of the major soil insect pests can be targeted for planting fungicide-only treated seed and experience little to no crop loss due to these insects.
The focus of this infosheet is how to use baits to find wireworm populations and how to dig and assess for grubs and some of the key root feeding pests. For full article, visit gfo.ca/Production/Production-ResourcesPests.
The Guide to Early Season Field Crop Pests provides additional information on how to scout for other soil insects.
Coming Events:
July 13 to 16 – Listowel Fair – 5699 Perth Line 86. Visit listowelfair.com or call 519-291-2776 for more information.
July 11; July 18 – Listowel Day 1 and 2 – Growing Forward 2 – Growing Your Farm Profits (GYFP) – Planning for Business Success. Start the business planning process by attending the two-day interactive workshop. You will assess business management practices, determine priorities and key goals, develop realistic action plans and learn about cost sharing funding opportunities. For more information and to register for workshops, visit ontariosoilcrop.org or call (519) 955-3139.
July 12; July 19 – Elora Day 1 and 2 – Growing Forward 2 – Canada-Ontario Environmental Farm Plan (EFP). Producers are invited to attend the EFP (Fourth Edition) two-day workshop to learn about best management practices, develop an action plan for their farm and learn about cost-sharing opportunities. For more information and to register for workshops, visit ontariosoilcrop.org or call 519-955-3139.
July 13 – FarmSmart Expo, Elora Research Station. For more information and to register, visit farmsmartconference.com/farmsmart-expo-2017.
