Building your soil health comes with the right balance of several different practices. Over the years we have worked to achieve healthier soil and cleaner water; however, one area we have only scratched the surface of is improved pest management. This workshop will focus on how to manage insect and slug populations with beneficial predators. Continue reading
By: Andy Michel and Kelley Tilmon
Note for Paulding County growers: If you suspect soybean aphids in your field, please call ANR Educator Sarah Noggle at 419-399-8225 with field location and soybean variety to have your field scouted and aphid sample taken for research purposes.
Soybean aphids have always been around Ohio, but it has been a while since we have had many fields with high populations. Based on recent scouting, we have noticed increasing populations of soybean aphids. As we go into the critical growth stage of soybean, this is also the most important time to check your fields for soybean aphids and see if you have exceeded the threshold of an increasing population of 250 aphids per plant.
To scout for soybean aphids, walk at least 100 ft from the field edge and count the number of aphids from 5 plants in 10 different locations. If your average is greater than 250 per plant, you’ll need to come back and re-scout 3-4 days later. If the aphid population increased in that time, an insecticide application is recommended. Keep in mind that to accurately determine the threshold, scouting should be performed at least weekly and multiple times a week if aphids are active in fields.
Soybean aphids can cause yield loss up to the late R5 to early R6 growth stage. If an application is necessary, there are several effective insecticides available. Although some soybean aphid populations in the western corn belt are resistant to pyrethroids, we have not seen any evidence of this in Ohio. If you make a pyrethroid application and suspect resistance, contact us, Andy Michel or Kelley Tilmon (email@example.com, firstname.lastname@example.org) or your local extension educator.
Press Release from Chris DiFonzo (Michigan State) and Kelley Tilmon (Ohio State)
The newly completed Michigan State/Ohio State Field Crops Insect Pest Management Guide is available for online use and downloads at https://aginsects.osu.edu/sites/aginsects/files/imce/MSU%20-%20OSU%20Insect%20IPM%20Guide.pdf
This publication contains a series of chapters with information on biology, damage, management recommendations, and insecticides related to insect pests in field crops in Michigan and Ohio. Chapters cover field corn, soybean, wheat, and other small grains, alfalfa and grass forage, and (for Michigan growers) dry beans and sugar beet. Each chapter stands alone, focusing on a particular crop.
In the preparation of this guide, we checked state databases and consulted labels for each of the pesticides listed in the crop chapters; we made every effort to include correct information and to list most of the commonly-used products for Michigan and Ohio. However, labels do change over time. Always read the labels of the products you use to reconfirm application rate, precautions, PPE, pre-harvest intervals, and other key pieces of information prior to spraying.
Users are the best source of feedback on this guide. If you see information that is not correct or complete, please contact us so that we can update the guide accordingly.
Kelley Tilmon, Mark Sulc, Andy Michel, James Morris
We have received an unusual number of reports about fall armyworm outbreaks particularly in forage including alfalfa and sorghum-sudangrass, and in turf. Certain hard-hit fields have been all but stripped bare (Figure 1). Armyworm is not typically a problem in Ohio in late summer, so we encourage farmers to be aware of feeding damage in their fields. Armyworms are much easier to kill when they are smaller, and feeding accelerates rapidly as they grow, so early detection is important. Look for egg masses glued not only to vegetation but to structures like fence posts. Egg masses have a fluffy-looking cover (Figure 2). When the cover is peeled back, eggs are pearly and tan when new, and turn darker as they approach egg-hatch.
Fall armyworm caterpillars vary in color from greenish to tan to dark brown with stripes along the body. They can be easily confused with other species, but a good identifier is an inverted white “Y” shape behind the head. (Figure 3). Another species, true armyworm, feeds at night but fall armyworm will feed during the day.
Insecticides will not penetrate egg masses well; it’s best to spray caterpillars when they are less than ¾ inches long, at which point most armyworm-labeled pyrethroids will kill them reasonably well. For larger caterpillars, products containing chlorantraniliprole will provide longer residual which may help with control of the harder-to-kill caterpillars over ¾ inches.
In forages, a threshold that can be used is 2-3 fall armyworm larvae per sq foot. If larvae are smaller (less than ¾ inch), they can still do a lot of feeding and are worth treating with an insecticide application. An early cut can help limit damage, but check the field for survivors. If survivors are abundant, an insecticide application may be warranted to protect nearby fields. Armyworms get their name from moving in large bodies (marching) to new feeding areas.
In corn, armyworms can randomly feed on leaves, with holes occurring throughout the leaf surface. The more damaging stage is when they feed on developing silks and kernels after entering the ear. Once they enter the ear, control by insecticides is much more difficult. Most Bt corn varieties with above-ground protection is labeled for armyworm control, but resistance to several Bt traits has appeared in the US. While we have not found Bt resistance in armyworms in Ohio, we would recommend growers scout ALL corn (Bt or non-Bt) for any evidence of damage or resistance. If feeding is found, please contact us (email@example.com, or firstname.lastname@example.org) or your local extension educator.
Fall armyworm does not overwinter in Ohio. Moths come up from the South early in the season and temporarily colonize the area, especially in grassy areas. The current caterpillars are second-generation. If we have a warm fall we could possibly see a problem third generation, especially in forage, cover crops, and winter wheat planted before the fly-free date (see Figure 4).
Please visit the Forages chapter in the Michigan State/Ohio State Field Crops Insect Pest Management Guide for management notes and labeled insecticides in forages. https://aginsects.osu.edu/sites/aginsects/files/imce/MSU%20-%20OSU%20Insect%20IPM%20Guide.pdf
Join us Friday, August 7th for our live webinar on the Great Lakes Early Detection Network App. Here is your opportunity to learn more about the app, how it is being used in Ohio, and how you can participate.
Help track invasive species using the Great Lakes Early Detection Network (GLEDN) App. Join Kathy Smith, Amy Stone, Marne Titchenell, and Eugene Braig, specialists in forestry, horticulture, wildlife, and aquatic ecology as they share how to use the app to report invasive species.
Register here: go.osu.edu/glednwebinar
By Kelley Tilmon, Andy Michel
As the summer progresses we are receiving reports of insect problems often encouraged by hot, dry weather. Last week we reported on spider mites and especially if you are in an area of continued dry weather we recommend scouting your soybeans and corn https://agcrops.osu.edu/newsletter/corn-newsletter/2020-22/watch-spider-mites-dry-areas .
Some areas are also reporting increases in young grasshoppers in soybeans, another insect favored by dry weather. Grasshoppers of often start on field edges so early scouting may allow for edge treatment. Japanese beetles are another common defoliator of soybean that are starting to appear. Both of these pests fall into a general defoliation measurement, and we recommend treatment if defoliation is approaching 20% on the majority of plants in post-flowering beans. Download our guide to estimating defoliation in soybean at https://aginsects.osu.edu/sites/aginsects/files/imce/Leaf%20Defoliators%20PDF_0.pdf Continue reading