First, I would like to introduce myself. I am Tim Bryant, the new assistant professor of entomology and extension specialist at the Tidewater AREC, in Suffolk, VA. I did my master’s degree here at the TAREC under Dr. Sally Taylor, and I am excited and grateful for the opportunity to come back and work with the farming community in Virginia. I am also looking forward to continuing to provide updates on this platform as regularly as we have updates to provide. Now, on to a quick update from my first few weeks on the job…
Soybean aphids have been reported in Mecklenburg and Prince George counties (First reports 8/28). Aphids can reproduce asexually, and are capable of rapid population growth under the right conditions, so close monitoring is important. Our threshold for managing soybean aphids is 250 per plant at R4 (full pod) or prior, and 1000+ at R5 (beginning seed) and beyond. The below image shows 300 aphids on a single leaflet as a point of reference (Photo credit: Roger Schmidt, University of Wisconsin-Madison, Bugwood.org). There is likely to be multiple developmental stages of aphids present at one time, and early stages are very small.
There are a couple key considerations for managing aphids; 1) they are highly susceptible to population crashes from natural enemies or weather events, and 2) broad-spectrum insecticide applications (i.e. pyrethroids) may kill aphids, but also the afore-mentioned beneficial insects. Eliminating beneficials can potentially flare up spider mites or other pests later on. If you think you may have an aphid problem, scout several areas of the field to estimate the number of aphids per plant and pay close attention to the number of beneficial insects present. Where we scouted for aphids, there were also large numbers of lady beetle adults and larvae, which are excellent aphid predators. If you reach the aphid threshold, sample again in 5-7 days to ensure the population has not crashed. Narrower spectrum insecticides (e.g. sivanto) may preserve some beneficial insects if an application for aphids is made. See our pest management guide (beginning on page “4-62”) for more details on labeled products, application rates, etc.
The below image shows a lady beetle larvae, which were found in abundance along with the aphids we are reporting on here, feeding on an aphid (Photo credit: Winston Beck, Iowa State University, Bugwood.org).
Corn earworm (= bollworm) moth catches were exceptionally high this week, continuing to climb in Dinwiddie, Prince George, and Suffolk, VA black light traps. The average number captured per night was 38 in Greensville, 79 in North Dinwiddie, 72 in Prince George/Disputanta, and 124 in Suffolk. Thanks to Sara Rutherford, Scott Reiter, and the Tidewater AREC entomology crew for their reports. Here is the Table.
Corn earworm (= bollworm) moth catches increased greatly this week in southeastern Virginia black light traps. The average number captured per night was 50 in Greensville, 42 in North Dinwiddie, 39 in Prince George/Disputanta, and 67 in Suffolk. Thanks to Sara Rutherford, Scott Reiter, and the Tidewater AREC entomology crew for their reports. Here is the Table.
We have evaluated over 250 moths in our 2024 vial tests, with 57% surviving the 24-hour exposure to the pyrethroid insecticide, cypermethrin, at 5 micrograms per vial.
Corn earworm (= bollworm) moth catches really started to increase this week in southeastern Virginia black light traps. The average number captured per night this week was 4 in Greensville, 11 in North Dinwiddie/Petersburg, 18 in Prince George/Disputanta, and 30 in Suffolk. Thanks to Sara Rutherford, Scott Reiter, and the Tidewater AREC entomology crew for their reports. Here is the Table
We have evaluated over 150 moths in our 2024 vial tests, with 61% surviving a 24-hour exposure to the pyrethroid insecticide, cypermethrin, at 5 micrograms per vial. Even though cypermethrin is no longer widely used, survival rates this high suggest we need to watch for some pyrethroid control failures, and to consider alternative chemistries when an insecticide is needed.
I want to remind everyone that the Virginia Ag Expo, Virginia’s largest field day, is next Thursday, Aug 4. The Expo is an educational, marketing, and social event that farmers and agribusiness look forward to each year. It moves from one location to another each year and strives to showcase the diversity of Virginia Agriculture. Our host this year is Mill Creek Farms and the event will be located at Camden Farm, which is located near Port Royal, right off of Highway 17 in Caroline County.
Precision for Profits is the theme for the 2022 Virginia Agricultural Expo. There will be a wide variety of agribusinesses present (currently over 85 exhibitors) showcasing the latest equipment, technology, goods, and services. Virginia Cooperative Extension will be working with NRCS to highlight the diversity of soils on this farm and the high potential for precision agriculture practices. Field plots are once again a walking, go-at-your-own-pace tour designed to fit your interest and schedule. Breakfast and Lunch will be catered by the vendors shown below.
The Virginia Ag Expo is jointly sponsored by the Virginia Grain Growers and Virginia Soybean Associations, in Cooperation with Virginia Cooperative Extension.
This event is FREE to the public. Click the link below to let us know you are coming!
The upcoming weekend rainfall (our meteorologists seem assured that it’ll be widespread) should greatly help parts of Virginia that are short on or getting short of topsoil moisture and position us perfectly for a good start to the soybean growing season.
However, with the rainfall comes cooler soil temperatures. Below are predictions for 4-inch soil moisture and soil temperature over the next 10 days from Orange (one of the coolest parts of Virginia) and Suffolk (one of the warmest parts). As you see, soil temperatures will plummet from relatively warm (>60o) to nearly 50o or less over the weekend. While soybean seed will germinate and emerge in a reasonable amount of time at 60O, germination and emergence will be very slow when temperatures dip below this.
Therefore, heed my suggestion and make sure that you have a good fungicide seed treatment on anything that you are planting now or early next week.
Below is the fungicide efficacy chart from our Pest Management Guide. The main diseases that we need to concern ourselves with are Rhizoctonia and Fusarium sp. If in wet soils, Pythium and Phytophtora sp. could also be a problem with slow-emerging soybean. Be sure to protect a slow-emerging crop with a fungicide containing the active ingredients that provide good to excellent control of the appropriate disease.
Many may have already planted. Some have stopped planting other crops such and peanut and cotton due to cool soils and started planting soybean instead. Regardless, an advantage of soybean is that it tolerates a wide range of planting dates. I’ve found no advantage to planting soybean before May and have seen little yield penalty from planting as late as the first week of June, under most conditions. There are advantages to planting early and planting late, but that is not the subject of this post. Contact me for more detailed discussion on this matter-it will take more that a few comments.
With that said, I’ve always preferred May planting due to less risk of frost damage and slow emergence that is common with earlier planting. Still there are big differences in management when planting in early- versus late-May. Here I’ll review a few of these.
Plant earliest maturing varieties first, then move to later maturing varieties. This will spread risk and harvest dates. We have however observed that early-planting and/or early-maturing varieties work better under productive soils/fields. If planting on poor soils/unproductive fields, later-maturing varieties will extend the growing season and push the critical pod- and seed-filling stages to less stressful times of the year.
Always plant into moisture. But don’t plant more than 1 inch deep when soils are cool or emergence will be delayed substantially. One-half to 3/4 of an inch is adequate. For later planting dates when soils are warm, one can plant as deep as 1.5 inches and get rapid emergence.
If planting into cool soils (usually before mid-May), use a good fungicide seed treatment. It could take 10 days or more for the soybean to emerge; plenty of time for soil-born seedling diseases to attack.
A final plant population of 70 to 100 thousand plants per acre is usually adequate for full-season plantings. This means that 95 to 130 thousand seed per acre is enough, depending on expected emergence. Our research and in other states have observed that less seed is needed with low-yielding fields and greater seeding rates are needed with high-yielding fields. The problem is knowing how much the field will yield.
As always, contact me for more details regarding these tips or discuss other early-season soybean issues.
Which soybean variety is best suited to my region? State variety testing programs provide critical research to help answer that question by evaluating hundreds of soybean varieties every year across multiple locations within a state. But what if we think beyond the bounds of our state borders when it comes to variety evaluation?
While a single state alone provides valuable data, our growing regions often cross state lines. A location in southeastern Virginia may share more similarities to sites in eastern North Carolina than it does to the Northern Piedmont of Virginia. Furthermore, by combining variety testing data across multiple states, we can create a more robust dataset that allows us to better predict which varieties are best suited to specific regions and growing conditions.
Pulling and combining data from select locations within multiple state variety testing programs can be a daunting task. Over the past year, a team of variety testing coordinators from Tennessee, Arkansas, Kentucky, North Carolina, and Virginia have been working to make that process a lot easier. Through funding from the United Soybean Board and in collaboration with Centrec Consulting Group, LLC, we created a tool that will allow users of variety test data to combine and visualize soybean variety testing data across multiple states in the Mid-South. This new tool is available at https://marketviewdb.centrec.com/?bi=MidSouthVarietyTrials.
In addition to choosing locations, another key component of this database is the ability to filter the results to include only the relative maturities, brands, and herbicide tolerances that you want. It can also let you chose whether to include irrigated and/or non-irrigated, or full-season and/or double-crop sites. You can also chose the soil textures that you are interested in.
I won’t go into the details of how to use the site in this blog. But, try it out. Contact me with questions or comments.
The database currently contains 2018 – 2020 data but will be updated as 2021 soybean variety trial data becomes available. We hope that you find this tool useful. We would value your feedback/suggestions as we continue to refine this product to better meet stakeholder needs. A brief survey can be found at https://utk.co1.qualtrics.com/jfe/form/SV_6u5lHEwEOXnXODA.
The database described in this article was developed with support from the United Soybean Board.
Until these big high-pressure systems sitting in the eastern part of the country move east, it looks as if we are in for another week or so of dry weather. This is not good for soybean planting, any way you look at it. So, what should we do?
There are basically three options:
Plant shallow in dry soil and hope for enough rain to get the seed out of the ground. If you decide to take this approach, you want to ensure you achieve uniform seed depth and that you are not allowing the seed access to moisture below the seed that could lead to variable emergence. This approach would be less risky in clean-tilled situation where you are more confident that you have dried the soil out at shallow depths. Soybean seed will sit in the ground for several weeks and still emerge well when rainfall occurs. Some worry about “cooking” the seed during this period. Although it is true that the seed will continue to respire and its ability to germinate will decline, the bigger risk is that you catch a small rain that allows the soybean seed to imbibe water but not enough to get it out of the ground.
Caution must be exercised in no-till systems. With no-till the soil has not been uniformly dried out with tillage; therefore, there is non-uniform moisture distribution across the field. This leads to uneven access to moisture and ultimately emergence variability. Parts of the field will have adequate moisture to get the soybeans out of the ground, other parts will be completely dry as in tilled conditions, and much of the field will be in between. Those in-between areas are likely to have enough moisture to swell the seed and/or initiate germination but not have enough moisture to allow the seedling to emerge. This is my least favorite option.
Plant deep to the moisture. Under most conditions, soybeans may be planted 0.75 to 1.5 inches deep. But I don’t usually like to go much over 1 inch deep, especially in May. I want soybean to come out of the ground as fast as possible. With that said, we planted some at 1.5 inches last week. Soil temperatures are generally high enough right now for the seed to germinate and plants emerge relatively quickly. Soybeans should not be planted deeper than 2 inches. Many are not finding soil moisture at less than 2 inches. Even if there is moisture 1.5 inches down, exercise caution using this approach, especially your soils are prone to crusting, because a heavy rainfall could seal the soil before the soybeans emerge. In tilled conditions, the planter can push the soil down a little, creating a ridge of fluffy soil on each side. A heavy rain will cause this soil to move into that furrow and possibly add another ½ to 1 inches of soil to your depth. If you are going to go this route, check the emergence score on the variety.
Keep the seed in the bag until the next time we catch rain. This is the safest approach and the one that I am leaning to now. Based on historical data, we have another couple of weeks before we start seeing yield declines from delayed planting. Data from recent research throughout the Mid-Atlantic shows that each day delay in planting past mid-June can result in a ½ bu/A or more yield loss and in general these yield declines begin in the second or third week of June. We still have some time before we get to that point. The optimum planting date range for soybeans is late-April through mid-June, although it will vary from year-to-year and field-to-field based on rainfall, soil water holding capacity, and soybean maturity, but the goal is to get the soybean plants to lap the middles before reproductive growth begins. We still have still have time to do this in most cases.
Waiting to plant
is more of a concern for those who still have early-maturing varieties to plant
(MG 3 and early-4), as these varieties will have less time for vegetative
growth. I do suggest planting your earliest maturity groups first, whichever strategy
you choose to employ. Later maturity
groups have more time for adequate growth when planting is delayed.
What about
fungicide seed treatments? You have likely already decided on this and cannot
change. But fungicidal seed treatments
are less likely needed in this situation where soils are warm. It looks as if
temperatures will be warming all week, so I don’t see cold soils as a problem.
Whatever decision
a grower makes, uniform seed placement in critical to achieve uniform emergence
and ensure each seed has as equal of access to water as possible. I don’t get too concerned if some
plants emerge just a few days apart, but we don’t need them emerging a week
apart. Dr.
Rachel Vann of N.C. State discussed the importance of uneven and delayed emergence
in soybeans – How
Important Is Uniform Emergence in Soybeans? Still, keep
in mind that although earlier emerging plants will usually yield more, the late
emerging plant will still contribute to yield.
Due to soybean’s compensatory ability, the yield on the whole will
differ little from only a few days difference in soybean emergence within the
row. If you know me, you know that I’m
not a fan of planting with drills due to lack of equal spacing within the row. This lack of even spacing will become
increasingly important if plant emergence is not good.
In conclusion,
there are advantages and disadvantages to each planting option discussed, but
we still have time to plant soybeans in our region before we see drastic yield
declines. All options discussed will likely result in delayed emergence due to
environmental conditions.
