Optimizing Early Season Pest Management for Maryland Field Corn

Maria Cramer, PhD Candidate and Kelly Hamby, Entomology Extension Specialist
Department of Entomology, University of Maryland

Background

Research Questions

  1. Are the NST Poncho 250® and the in-furrow pyrethroid Capture LFR® effective at controlling pests and increasing yield in high-input (Bt) or low-input (non-Bt) field corn in Maryland?
  2. Do Poncho and Capture hurt slug predators and flare up slug damage?

Study Design

In order to capture the range of pest pressures and growing conditions in Maryland, we replicated our study across 3 UMD research farms (Keedysville, Beltsville, and Queenstown) and over 3 years (2020-2022). At each location we planted one field of a Bt hybrid and one field of a similarly-yielding non-Bt hybrid as early as possible in the growing season (Table 1). In 2020 our Bt hybrid was LC1196 VT2P (Local Seed, Memphis, TN) which expresses Cry1A.105/Cry2Ab2 proteins. In 2021 and 2022 we planted P1197YHR (Pioneer Hi-bred International. Johnston, IA) which contains Cry1Ab and Cry1F proteins. We planted P1197LR (Pioneer Hi-bred International, Inc. Johnston, IA) for our non-Bt hybrid all three years. All hybrids had excellent yield potential and were grown with standard no-till practices. In each field we established 3 replicates of 3 treatments at planting: 1) an untreated control, with bare seed and no in-furrow product, 2) an in-furrow pyrethroid treatment using Capture LFR® (active ingredient: bifenthrin, rate: 13.6 fl oz/acre), and 3) an NST treatment using Poncho® (active ingredient: clothianidin, rate: 0.25 mg/seed). Each replicate consisted of 24 rows of corn at 30 inch row spacing, and was 200 feet long.

Year Location Planting date Sampling dates
2020 Keedysville May 18 June 8
Beltsville May 21 June 10
Queenstown May 13 June 3 and 4
2021 Keedysville May 14 June 1 and 3
Beltsville May 17 June 2
Queenstown May 4 May 25 and 26
2022 Keedysville May 26 June 10
Beltsville June 2 June 21
Queenstown May 12 May 31

Question 1: Are the NST Poncho 250® and the in-furrow pyrethroid Capture LFR® effective at controlling pests and increasing yield in high-input (Bt) or low-input (non-Bt) field corn in Maryland?

Data Collection

In order to evaluate how the treatments affected pest pressure, we visually sampled V2-V3 corn for types of pest damage (Figure 1), recording the number of plants and area damaged. We counted the number of healthy and stunted plants to determine if the treatments impacted stand. Because neonicotinoids can sometimes stimulate plant growth unrelated to pest damage7,8, we measured plant height to determine if plant growth was impacted by either treatment. At the end of the growing season, we measured stand again and harvested the corn to collect yield data.

Figure 1. Diagnostic seedling pest damage: a) soil pest, b) cutworm, c) armyworm, d) slug, e) stinkbug, f) miscellaneous feeding damage from a spotted cucumber beetle.

Results and Takeaways for Question 1

Poncho reduced insect damage more consistently than Capture LFR (in both Bt and non-Bt corn) and increased Bt corn stand. Capture LFR sometimes reduced insect damage (in non-Bt corn), but never improved stand.

We compared the number of seedlings with any type of pest damage between treatments and found that Poncho decreased damage about 62% in Bt corn and about 66% in non-Bt corn (Figure 2a and 2b). Compared to the control, Capture did not reduce damage in the Bt corn, but did reduce damage by about half in the non-Bt. Poncho increased stand about 8% compared to control in the Bt corn (25,731 ± 456 plants per acre and 23,623 ± 714 plants per acre, respectively), but did not improve it for non-Bt. Capture did not impact stand for either Bt or non-Bt corn.

Figure 2. Mean % ± SE of seedling A) Bt and B) non-Bt corn plants damaged by pests. Data were collected across three UMD research farms from 2020-2022. Within each graph, treatment bars with different letter above them are significantly different from each other.

There were no yield benefits from using either insecticide in either corn. This was likely due to a lack of economic pest pressure.

Non-Bt and Bt yields were the same across treatments (Figure 3A and 3B). This was probably because pest pressure was so low. Even though Poncho and Capture decreased pest damage, pests were below treatment thresholds—for example, armyworm damage in the control ranged from 0% to 5.4% of Bt plants, and 0% to 22.9% of non-Bt plants, in both cases below the treatment threshold of 35%9. Cutworm damage was similarly low ranging from 1% to 6.3% in Bt control and 0.5% to 3.8% in non-Bt control, also below the treatment threshold of 10% feeding damage9.

Figure 3. Mean yield ± standard error in bushels per acre corrected to 15.5% moisture of A) Bt corn and B) non-Bt corn. Yield data from 2020-2022 across three UMD research farms. Treatments did not significantly impact yield.

Takeaway: Pest pressure and yield were similar between the Bt and non-Bt varieties, and non-Bt yielded well without any insecticides. In general, without pre-existing pest problems in a given field, at-planting insecticides are unlikely to pay off in Maryland.

Question 2: Do Poncho and Capture hurt slug predators and flare up slug damage?

Data Collection

To assess the effect of treatments on slug biocontrol agents, we measured slug predatory ground beetles and predation. We measured predatory beetles with pitfall traps for three consecutive weeks. Because the predators that eat slugs also attack caterpillars, we used sentinel caterpillars to see how much predation was occurring (Figure 4). We placed sentinel caterpillars in the plots overnight, collected them the following morning, and assessed signs of damage from predators. To determine if slugs were flared up by the treatments, we measured slug abundance once a week for 6 weeks beginning between 14 to 21 days after planting and measured slug-damaged seedlings during V2-V3.

Figure 4. Sentinel caterpillars placed in field overnight and collected in the morning to determine predator activity.

Results and Takeaways for Question 2

Predation on sentinel caterpillars was not decreased by insecticides.

We measured the percent of sentinel prey that were damaged by predators overnight (Figure 5) and saw no relationship between treatment and predation rates (Figure 6). This suggests that the insecticides did not decrease predator activity in treated plots. We did generally see some level of predation all weeks at our locations, indicating that predators are usually present in seedling corn.

Figure 5. Top: predators feeding on sentinel prey. Bottom: examples of damaged prey proportions. Images: M. Cramer, University of Maryland.
Figure 6. Mean ± SE % sentinel prey caterpillars consumed across three UMD research farms from 2020-2022. Control, Capture, and Poncho did not significantly differ.

Predator abundance was not altered by insecticides.

When we measured the weekly counts of ground beetles, we found similar results between treatments. This was true when we looked at all ground beetles (predators, omnivores, and seed-eaters), as well as when we looked only at predatory beetles (Figure 7A and 7B).

Figure 7. Mean ± SE count of A) all ground beetles, and B) specifically predatory ground beetles, caught per week in pitfall traps across three UMD research farms from 2020-2022. No significant differences.

Slug natural enemies did occur throughout the study, suggesting that biocontrol could be more intentionally leveraged.

The two most abundant ground beetle species in our study were both predators. One of these species, Chlaenius tricolor (Figure 8) is a slug predator that consumes slugs in agricultural ecosystems5,10. Although its abundance was not affected by treatments, it was present at all locations in all years, suggesting that it is a particularly important slug natural enemy in Maryland crops.

Figure 8. Chlaenius tricolor, a slug predator that was found throughout the study. Photo credit: ©Molanic 2023: https://www.inaturalist.org/photos/314013175.

Neither insecticide increased slug abundance or slug damage.

If treatments had negatively affected predators, we would expect to see more slugs and damage in the insecticide plots. However, when we compared slug counts between treatments, we found that the insecticide treatments were not different from the control (Figure 9). Slug damage to the seedling corn was also similar across the control and insecticide treatments (Figure 10).

Figure 9. Mean number of slugs per replicate plot ± SE the week closest to seedling sampling across three UMD research farms from 2020-2022. No significant differences.
Figure 10. Mean ± SE % of corn seedlings damaged by slugs across three UMD research farms from 2020-2022. Control. No significant differences.

While slugs can be damaging in many crops, the worst slug damage in our study did not affect corn stand or yield, suggesting that corn is generally tolerant of slug damage at the levels we observed in this study.

Slug damage was scarce across years and locations except in 2021 at Keedysville. Even in that case where a high proportion of seedlings (42% ± 4% on average) were damaged by slugs, we did not see an associated decrease in stand or yield. Corn seedlings were able to outgrow the slug damage as the weather warmed, even when they appeared severely defoliated. The seedling resilience we observed is supported by work on hail damage in corn which shows that as long as the growing point is intact, corn can regrow from complete defoliation11.

Even though we did not see non-target effects in this study, both pyrethroids and neonicotinoids can decrease natural enemies in crop fields6,12–14.

Acknowledgments

We would like to thank the farm managers and staff of WYEREC, WMREC, and CMREC Beltsville for their expertise and assistance. We would also like to thank the Hamby lab’s many undergraduate researchers for helping complete this project with all their hard work.

Sources:

  1. Kullik, S. A., Sears, M. K. & Schaafsma, A. W. Sublethal Effects of Cry 1F Bt Corn and Clothianidin on Black Cutworm (Lepidoptera: Noctuidae) Larval Development. J. Econ. Entomol. 104, 484–493 (2011).
  2. North, J. H. et al. Value of neonicotinoid insecticide seed treatments in mid-south corn (Zea mays) production systems. J. Econ. Entomol. 111, 187–192 (2018).
  3. Reisig, D. & Goldsworthy, E. Efficacy of Insecticidal Seed Treatments and Bifenthrin In-Furrow for Annual White Grub, 2016. Arthropod Manag. Tests 43, 1–2 (2017).
  4. Sappington, T. W., Hesler, L. S., Clint Allen, K., Luttrell, R. G. & Papiernik, S. K. Prevalence of sporadic insect pests of seedling corn and factors affecting risk of infestation. J. Integr. Pest Manag. 9, (2018).
  5. Douglas, M. R., Rohr, J. R. & Tooker, J. F. Neonicotinoid insecticide travels through a soil food chain, disrupting biological control of non-target pests and decreasing soya bean yield. J. Appl. Ecol. 52, 250–260 (2015).
  6. Dubey, A., Lewis, M. T., Dively, G. P. & Hamby, K. A. Ecological impacts of pesticide seed treatments on arthropod communities in a grain crop rotation. J. Appl. Ecol. 57, 936–951 (2020).
  7. Ding, J. et al. Thiamethoxam, clothianidin, and imidacloprid seed treatments effectively control thrips on corn under field conditions. J. Insect Sci. 18, (2018).
  8. Preetha, G. & Stanley, J. Influence of neonicotinoid insecticides on the plant growth attributes of cotton and okra. J. Plant Nutr. 35, 1234–1245 (2012).
  9. Flessner, M. & Taylor, S. V. 2021 Field Crops Pest Management Guide. Virginia Cooperative Extension (2021) doi:10.1016/B978-0-12-394807-6.00031-9.
  10. Eskelson, M. J., Chapman, E. G., Archbold, D. D., Obrycki, J. J. & Harwood, J. D. Molecular identification of predation by carabid beetles on exotic and native slugs in a strawberry agroecosystem. Biol. Control 56, 245–253 (2011).
  11. Thomason, W. & Battaglia, M. Early defoliation effects on corn plant stands and grain yield. Agron. J. 5024–5032 (2020) doi:10.1002/agj2.20402.
  12. Disque, H. H., Hamby, K. A., Dubey, A., Taylor, C. & Dively, G. P. Effects of clothianidin-treated seed on the arthropod community in a mid-Atlantic no-till corn agroecosystem. Pest Manag. Sci. 75, 969–978 (2019).
  13. Bhatti, M. A. et al. Field Evaluation of the Impact of Corn Rootworm (Coleoptera: Chrysomelidae)–Protected <I>Bt</I> Corn on Foliage-Dwelling Arthropods. Environ. Entomol. 34, 1336–1345 (2006).
  14. Taravati, S., Mannion, C., McKenzie, C. & Osborne, L. Lethal and Sublethal Effects of Selected Systemic and Contact Insecticides on Nephaspis oculata (Coleoptera: Coccinellidae), in a Tri-Trophic System. J. Econ. Entomol. 112, 543–548 (2018).

Can Flame Weeding be used for Early-Season Weed Control in Soybean?

Kurt Vollmer, Dwayne Joseph, and Alan Leslie
University of Maryland

Figure 1. A flame treatment is applied to control emerged weeds in soybean.

Starting clean or weed-free is the key to a good weed control program, especially when noxious weeds, such as Palmer amaranth are present. While conventional growers can use soil-active herbicides to manage these weeds, control is more complicated in organic systems. Flame weeding is a non-chemical tactic that has been shown to control several grass and broadleaf weed species. The majority of flame weeding treatments are applied to emerged weeds; however, studies have also shown flame treatments to have detrimental effects on the seeds of certain weed species post-dispersal. Furthermore, seeds from species such as horseweed (marestail) and Palmer amaranth tend to germinate from shallower depths in the soil profile, and may be more readily controlled by flaming on or near the soil surface. Cultivation/tillage is another tactic that can be used to control weeds in both conventional and organic systems. However, cultivation can lead to additional weed emergence and cannot be used when the soil is wet. Flame weeding may help to supplement weed control when cultivation is not an option.

In 2023, a study funded by the Maryland Soybean Board was conducted at sites in Caroline and Kent county Maryland to evaluate flame-weeding as an integrated tactic for early-season weed control in soybean (Table 1). All plots were flamed immediately after planting followed by 1 or 2 additional flame treatments or flame treatments integrated with a cultivation treatment when weeds reached 3” in height. In addition, different walking speeds (1 and 2 mph) were tested to determine if longer flame exposure improved weed control. All flame treatments were made using a propane-powered Inferno Flame Weeder (Neversink Farms, Figure 1), and cultivation was done using a 25cc 2-cycle gas-powered cultivator (Craftsman).

Table 1. Integrated flame-weeding treatments.

Treatment No. Treatment Speed

(mph)

1 Flame at planting 1
2 Flame at planting fb* flame 3” weeds 1
3 Flame at planting fb flame 3” weeds fb flame 3” weeds 1
4 Flame at planting fb cultivation 3” weeds fb flame 3” weeds 1
5 Flame at planting fb cultivation 3” weeds 1
6 Flame at planting 2
7 Flame at planting fb flame 3” weeds 2
8 Flame at planting fb flame 3” weeds fb flame 3” weeds 2
9 Flame at planting fb cultivation 3” weeds fb flame 3” weeds 2
10 Flame at planting fb cultivation 3” weeds 2
*fb= followed by

Results from both studies showed that flame treatments affected overall broadleaf density, but cultivation was needed to attain higher levels of control. Flame treatments alone helped to reduce weed density at the Kent County study relative to the untreated check, with three subsequent flame treatments showing a reduction in broadleaf weed density compared to one or two flame treatments (Figure 2).

Figure 2 (left). Broadleaf weed density at the Kent County site 5 weeks after planting. Figure 3 (right). Palmer amaranth density at the Caroline County site 4 weeks after planting. Values followed by the same letter are not significantly different according to Student’s T-Test (α = 0.05).

While a diversity of species were present at the Kent County site, Palmer amaranth was the dominant species at the Caroline County site. At this site both treatment and walking speed had an effect on Palmer amaranth density 4 weeks after planting. While the majority of flame treatments did not differ from one another, Palmer amaranth density was lower with 3 subsequent flame treatments at 1 mph compared 3 subsequent flame treatments at 2 mph (Figure 3). Similar results were observed with the flame followed by cultivation followed by flame treatment suggesting that longer flame exposure may be needed for effective Palmer amaranth control. It should also be noted that Palmer amaranth varied in height at the time of postemergence applications, with flame treatments having a reduced effect on larger weeds (Figure 4).

Figure 4. Palmer amaranth injury following flame weeding.

While results from both sites showed that flame treatments can reduce weed density, weed control was not maintained at acceptable levels throughout the growing season. In the case of the Caroline County site, the level of the Palmer amaranth infestation was too high to produce a viable crop. These results suggest that preemergence flame treatments are not a viable option for weed management compared to postemergence flame treatments. However, additional research is needed to determine how postemergence flame treatments may be better integrated into a more comprehensive weed control program.

2023 Maryland Corn Hybrid Trial Results

Nicole Fiorellino, Extension Agronomist | nfiorell@umd.edu
University of Maryland, College Park

Please find attached a copy of the 2023 Corn Hybrid Trials results performed annually at multiple UMD Research and Education Centers. The factsheet can also be downloaded from the MD Crops website at https://psla.umd.edu/extension/md-crops. Many thanks to Louis Thorne and Joe Crank for their leadership and management of the trials, from seed organization, to planting, to harvest. These trials could not be completed without them.

We are grateful for the funding provided by Maryland Grain Producers Utilization Board to support these trials. MGPUB provides our program with checkoff funding to support applied agricultural research and generate results that directly benefit Maryland producers.

For more information on how to interpret and utilize hybrid/variety trial data, check out our fact sheet, What do the numbers really mean? Interpreting variety trial results.

Click here to download the 2023 corn hybrid results

Maryland Grain Producers Scholarships

The Maryland Grain Producers are offering a total of $15,000 through seven scholarships for the 2024 to 2025 school year. There are three different scholarship opportunities for Grain Producer Members and non-members. Applications are due online by January 31st.

“The number of strong applications received for the first year of our new program showed our board the value and need to support all of our members and those interested in agriculture.” said Maryland Grain Producer Association President, Justin Brendel. The three different scholarship opportunities are outlined below.

  • Maryland Grain Honoree Scholarship
  • Awarding three scholarships in the amount of $3,000 each.
  • Must be a member of the Maryland Grain Producers Association.
  • Must be attending a secondary education school studying agriculture or working towards a degree to directly benefit the agriculture industry.
  • Maryland Grain Membership Scholarship
  • Awarding two scholarships in the amount of $2,000 each.
  • Must be a member of the Maryland Grain Producers Association.
  • Must be attending a secondary education school, with any area of study.
  • Maryland Grain Production Scholarship
  • Awarding two scholarships in the amount of $1,000 each.
  • Must be attending a secondary education school studying agriculture or working towards a degree to directly benefit the agriculture industry.

For the three different opportunities all applicants are only eligible to receive a scholarship two times and only eligible to apply for one of the three scholarships available. One’s family farm may not have requested Maryland grain checkoff refunds in the last 12 months. Lastly, graduate students are ineligible to apply.

In addition to our scholarship program, those eligible for the Honoree and Membership Scholarship, as well as grad students, would be eligible for the National Corn Growers Scholarships, please visit their website here to learn more and apply online.

For more information and to apply online for our 2024 scholarship program, visit our website at MarylandGrain.org/Scholarship-3/. Please contact our team if you have any questions.

For questions, contact Jenell McHenry – jenell.mdag@gmail.com – 443-262-6969.

October 2023 Grain Market Update

Information from USDA WASDE report

Attached is the summary for the October 2023 WASDE.

Corn

This month’s 2023/24 U.S. corn outlook is for reduced supplies, lower feed and residual use and exports, and smaller ending stocks. Corn production is forecast at 15.064 billion bushels, down 70 million on a cut in yield to 173.0 bushels per acre. Corn supplies are forecast at 16.451 billion bushels, a decline of 160 million bushels from last month, with lower production and beginning stocks. Exports are reduced by 25 million bushels reflecting smaller supplies and slow early-season demand. Feed and residual use is down 25 million bushels based on lower supply. With supply falling more than use, corn ending stocks for 2023/24 are lowered 110 million bushels. The season-average corn price received by producers is raised 5 cents to $4.95 per bushel.

Soybean

Soybean production is forecast at 4.1 billion bushels, down 42 million on lower yields. Harvested area is unchanged at 82.8 million acres. The soybean yield is projected at 49.6 bushels per acre, down 0.5 bushels from the September forecast. The largest production changes are for Kansas, Michigan, and Nebraska. With lower production partly offset by higher beginning stocks, supplies are reduced 24 million bushels. Soybean exports are reduced 35 million bushels to 1.76 billion with increased competition from South America. Soybean crush is projected at 2.3 billion bushels, up 10 million, driven by higher soybean meal exports and soybean oil domestic demand. Soybean oil domestic use is raised in line with an increase for 2022/23. With lower exports partly offset by increased crush, ending stocks are unchanged from last month at 220 million bushels. 

Wheat

The outlook for 2023/24 U.S. wheat this month is for higher supplies, increased domestic use, unchanged exports, and higher ending stocks. Supplies are raised 85 million bushels, primarily on higher production as reported in the NASS Small Grains Annual Summary, released September 29. Domestic use is raised 30 million bushels, all on higher feed and residual use. The NASS Grain Stocks report released September 29 indicated a higher year-to-year increase for first quarter (June-August) domestic disappearance than previously expected. Exports remain at 700 million bushels with several offsetting by-class changes. Projected ending stocks are raised by 55 million bushels to 670 million, up 15 percent from last year. The season average farm price is reduced $0.20 per bushel to $7.30 on higher projected stocks and expectations for futures and cash prices for the remainder of the marketing year.

Tar Spot Confirmed in Additional Counties in Maryland

Andrew Kness, Senior Agriculture Agent | akness@umd.edu
University of Maryland Extension, Harford County

During the month of September we have confirmed the presence of tar spot of corn in four additional counties in Maryland. Fields with tar spot in Queen Anne’s and Kent County were found on September 19, Baltimore County on September 22, and Caroline County on September 25, and Dorchester County on October 6. This brings the confirmed distribution from Carroll County east to Cecil and south on the shore to Dorchester County (Figure 1). In my scouting travels a few weeks ago on the eastern shore, I was able to find tar spot in two out of a dozen fields that I visited.

Figure 1. Tar spot confirmed distribution as of October 9, 2023. Map downloaded from https://corn.ipmpipe.org/tarspot/.

Note that this is the confirmed distribution—this is not to say that you will not find it outside of these reported counties; as a matter of fact, I’d be surprised if it’s not out there in several other areas across the state. As you harvest corn this fall, it might not be a bad idea to hop out of the cab and check around. Tar spot can still be visible on dry, senesced tissue. The signs of tar spot are dark black, raised spots that resemble spattered black paint (Figure 2). These spots are the reproductive structures of the fungus, Phyllachora maydis. These structures, called stromata, are embedded in the leaf tissue, are slightly raised (visible under a hand lens), and cannot be rubbed or scratched off the leaf.

Figure 2. Signs of tar spot on corn.

When you are scouting you may notice several look-alikes that can fool you. Insect frass (poop) is one that looks very similar but you can wipe the spots off the leaf. You may also notice other fungi present on senesced tissue, giving the leaves a black appearance. These fungi are not tar spot but are instead secondary decomposers—i.e. they colonize dead plant tissue. You can distinguish these fungi from tar spot by looking closely at the spots. Tar spot will be strikingly dark black against the dead tissue and slightly raised, whereas these secondary fungi are less distinct and not raised (Figure 3). Also, tar spot infections start on green tissue that is still alive, so check the few green leaves that are still present for signs.

Figure 3. Tar spot on a senesced corn leaf vs. look-a-likes. Stromata are still easily visible on dead leaves. Dull, faded/blurred spots are not tar spot.

As far as management considerations for this year and moving into 2024: tillage has varied success and generally has very little effect on tar spot. While tar spot does overwinter on old crop residue and tillage can help accelerate residue decomposition, research from the Midwest has shown highly inconsistent responses to tillage for managing tar spot. A couple of reasons for this is because tar spot can be wind-blown short distances; and with the concentration of corn fields present in many areas of the state, inoculum can blow into “clean” fields from nearby infected fields. Another reason that tillage doesn’t have a major effect is because most tillage equipment (besides a moldboard plow) leaves at least some residue on the soil surface. Those exposed crop residues can be enough to get an infection started the following year.

A more effective management tactic to consider is hybrid genetics. While there is no complete resistance to tar spot, there are hybrids that tolerate it much better than others. Using more resistant hybrids next year can help manage this disease, especially in fields where you suspect that tar spot could be an issue. In addition, you can use planting date and hybrid maturity to your advantage. The combination of early planting and a early-maturing hybrids can be used to “avoid” tar spot infections by having corn beyond its critical growth stages (VT-R2) before cooler weather sets in later in the season, which is favorable to tar spot infection.

If you find tar spot in your fields, please report it by emailing akness@umd.edu or submitting a report at https://corn.ipmpipe.org/reporting-form/.

Scout for Aphids in Small Grains

Kelly Hamby, Associate Professor and Extension Specialist, University of Maryland and
David Owens, Extension Entomologist, University of Delaware

Figure 1. Barley Yellow Dwarf patch in a field of malting barley, March 2023. Photo: David Owens, Univ. of Delaware.

Last season, aphids transmitted an unusual amount of barley yellow dwarf virus (BYDV) to wheat and barley across the Delmarva Peninsula. BYDV is particularly important when it infects plants in the fall. Fall BYDV infections can stunt plants (noticed as early as green-up, Figure 1) and cause more serious yield loss than spring infections. Our most common small grain aphid species are bird cherry oat aphid (Figure 2) and English grain aphid, although bird cherry oat aphid are associated with greater and more severe incidence of BYDV.

Figure 2. Bird cherry-oat aphids.

Historically, planting after the Hessian fly-free date (Table 1) reduced the likelihood of fall BYDV infection. However, fly-free dates were calculated more than 100 years ago, and it is now not uncommon for our first killing frosts to occur in late October or even November. Long falls with milder weather allow more time for aphids to colonize fields and potentially transmit the virus. Small grains varieties vary in their susceptibility to BYDV, and planting varieties with at least some tolerance can help. Unfortunately, resistant varieties are not available in barley. Finally, monitoring and managing the aphid vectors may be necessary.

Identifying bird cherry-oat aphid: A magnifying hand lens is required to identify aphids. Bird cherry-oat aphid ranges from orange green to olive green to greenish black. Wingless individuals typically have a reddish orange patch around the base of the cornicles (tail pipes). Winged individuals tend to be very dark. Their legs, cornicles, and antennae are similar in color to their bodies and medium in size.

Monitoring and thresholds: Typically, monitoring aphids in the fall and at green-up provides the best chance of identifying and mitigating BYDV risk. Scout ten locations per field avoiding field margins and look at 1 ft of row in each, making sure to look at the crown (at or below ground level), at the stem, and on the undersides of leaves. English grain aphids tend to feed on the uppermost portions of the plants while bird cherry oat aphids tend to cluster on the lower portions, especially in barley.

University extension threshold recommendations vary by region. In southern states, 6 aphids/row-ft is considered justification for a treatment in the fall. North Carolina uses a threshold of 20 aphids/row-ft where BYDV has been a problem and cold weather is not in the 7 day forecast. For other small grains, consider increasing the threshold to 25-50 aphids per foot of row.

In 2022, one of the malting barley fields sampled averaged 17 aphids per row-ft in early November. Because of unusually warm winter weather in which average temperatures were greater than 38 degrees, aphid populations peaked in one field at 235 aphids per row-ft that had averaged 1.8 per row-ft in November. This highlights the need to regularly monitor aphid populations during periods of mild weather.

Natural enemies: A number of natural enemies feed upon or parasitize aphids and they often do a good job keeping aphid populations down. One natural enemy per 50-100 aphids should be sufficient to control aphid populations. In addition, they are good at finding aphids even when their populations are low. Small wasps that develop within aphids leaving behind “mummy” aphids (Figure 3A), lady beetles, lacewing larvae (Figure 3B), and flower fly larvae (Figure 3C) are especially common aphid natural enemies. Insecticides will also kill these natural enemies.

Figure 3. Aphid natural enemies A) parasitoid wasp and golden or tan colored “mummy” aphids, B) lacewing larva eating aphids, C) flower fly larva eating aphids. Images: David Cappaert, Bugwood.org.

Insecticides: Seed treatments (e.g., Cruiser, Gaucho) provide some protection from fall aphids, but do not continue to provide protection into the spring and are not economic in years where aphids do not occur. Due to the differences in economics and BYDV susceptibility of malting barley varieties, seed treatments may be more useful than in feed barley or wheat. We generally recommend a foliar insecticide when aphid populations reach threshold. Small grain aphids are generally quite susceptible to insecticides. Pyrethroid products (e.g., Warrior) or a pyrethroid-neonicotinoid mix (e.g., Endigo, labeled for barley only) work well for aphid control.

 

Table 1. Hessian fly-free dates for Maryland and Delaware counties

State County Date
Maryland Allegany Sept. 27
Anne Arundel Oct. 7
Baltimore Oct. 2
Calvert Oct. 8
Caroline Oct. 7
Carroll Sept. 28
Cecil Oct. 3
Charles Oct. 8
Dorchester Oct. 9
Frederick Oct. 2
Garrett Sept. 20
Harford Oct. 1
Howard Oct. 2
Kent Oct. 6
Montgomery Oct. 4
Prince George’s Oct. 7
Queen Anne’s Oct. 7
Somerset Oct. 10
St. Mary’s Oct. 9
Talbot Oct. 8
Washington Oct. 1
Wicomico Oct. 10
Worcester Oct. 11
Delaware Kent Oct. 8
New Castle Oct. 3
Sussex Oct. 10

More information:

Kleczewski, N., Cissel, B., Whalen, J. 2016. Barley Yellow Dwarf Management in Small Grains. http://cdn.extension.udel.edu/wp-content/uploads/2015/10/14051904/BYDV-Final-Draft-9-12-16.pdf.

Flanders, K., Herbert, A., Buntin, D., Johnson, D., Bowen, K., Murphy, J. F., Chapin, J., Hagan, A. 2006. Barley Yellow Dwarf in Small Grains in the Southeast. https://entomology.ca.uky.edu/files/efpdf1/ef150.pdf.

Owens, D. and B. Cissel. Insect Control in Small Grains (for Grain only) – 2020. https://www.udel.edu/content/dam/udelImages/canr/pdfs/extension/sustainable-agriculture/pest-management/Insect_Control_in_Small_Grains_2020.pdf.

 

Don’t Forget to Register for Crop School

crop management school logo

November 14-16, 2023 | Princess Royale Oceanfront Resort, Ocean City, MD

About the School

The school offers a 2 ½-day in person format with a variety of breakout sessions. Individuals needing training in soil and water, nutrient management, crop management, and pest management can create their own schedule by choosing from 5 program options offered each hour. Emphasis is placed on new and advanced information with group discussion and interaction encouraged.

Who Should Attend

This school is designed for anyone interested in crop management issues, including:

  • agronomists
  • crop consultants
  • extension educators
  • farmers and farm managers
  • pesticide dealers, distributors, and applicators
    seed and agrichemical company representatives
    soil conservationists
  • state department of agriculture personnel

Continuing Education Credits

The 2023 Mid-Atlantic Crop Management School will offer CCA continuing education units (CEUs) approved by the Certified Crop Adviser Program in the following categories:

  • Crop Management
  • Professional Development
  • Pest Management
  • Sustainability
  • Soil & Water Management
  • Nutrient Management

Total CEUs earned will depend on course selection. This school also provides Pesticide Recertification Credits for DE, MD, NJ, PA, WV, and VA and continuing education for Nutrient Management Consultants in DE, MD, PA, VA, and WV.

Registration Information
The early-bird registration fee (recommended to ensure a place in the sessions of your choice) is $325 if received by October 13th; $375 if received by November 6th. Registration will close on Monday, November 6th at 11:59 p.m. ET or when enrollment reaches capacity. Payment of registration fee entitles you to participation in 2½ days of sessions, materials, 3 continental breakfasts, 2 lunches, and refreshment breaks.

*New for 2023: The Mid-Atlantic CCA Board will be hosting an off-site reception on Wednesday November 15th, with transportation and refreshments sponsored by the Board. Please RSVP for the reception when you register for the event as seating at the reception is limited.

Please Register for the 2023 Crop School Program at: https://bit.ly/CropSchool23

The 2023 event booklet and description of courses can be found here. Please read over the classes prior to registration as you will be required to select all of your courses during the registration process.

Feel free to contact Taylor Garrett, tgarret1@umd.edu or Dr. Nicole Fiorellino, nfiorell@umd.edu with any questions.

We look forward to an exciting and educational filled 2023 Mid-Atlantic Crop School with you!

2023/2024 UME Pesticide & Nutrient Management Trainings

Upcoming training opportunities through UMD Extension. Please register in advance.

Private Pesticide Applicator Recertification
Date Time Location Registration
October 26, 2023 6-8 PM St. Mary’s Extension office 301-475-4482
November 1, 2023 1-3 PM Baltimore County Extension office 410-887-8090
November 7, 2023 1-3 PM Harford County Extension office 410-638-3255
November 29, 2023 6-8 PM Barns of New Market Charlotte Hall 301-475-4482
November 29, 2023 6-8 PM Carroll County Extension office 410-386-2760
November 30, 2023 6-8 PM Wicomico County Extension office 410-749-6141
December 13, 2023 6-8 PM Mt. Airy Volunteer Fire Company 301-600-1594
December 14, 2023 6-9 PM Anne Arundel County Extension office 410-222-3900
December 20, 2023 8-10 AM Somerset County Extension office 410-651-1350

 

Pesticide Private Applicator Recertification
Date Time Location Registration
February 5, 2024 5:30-7:30 PM Carroll County Extension Office 410-386-2760
February 8, 2024* All Day Frederick 4-H Camp 301-600-1594
February 15, 2024 7-9 PM Washington County Extension office 301-791-1304
March 5 2024 6-9 PM Talbot County Ag Center 410-822-1244
March 12, 2024 6-9 PM Anne Arundel County Extension office 410-222-3900
March 26, 2024 1-3 PM Harford County Extension office 410-638-3255
April 2, 2024 6-8 PM Live online training 410-222-3900

*February 8, 2024 meeting is commercial agriculture pesticide meeting

Pesticide Private Applicator Optional Prep Class and Exam
Date Time Location Registration
Class: November 1, 2023

Exam: November 8, 2023

9-11 AM Baltimore County Extension office 410-887-8090
Class: November 1, 2023

Exam: November 8, 2023

8-10 AM

6-8 PM

St. Mary’s County Extension office 301-475-4482
Class: November 2, 2023

Exam: November 9, 2023

6-8 PM Carroll County Extension office 410-386-2760
Class: November 6, 2023

Exam: November 13, 2023

6-8 PM Frederick County Extension office 301-600-1594
Class: November 8, 2023

Exam: November 15, 2023

1-3 PM Washington County Extension office 301-791-1304
Class: November 28, 2023 6-8 PM Kent County Extension office 443-480-8369
Class: January 9, 2024

Exam: January 23, 2024

6-8 PM Anne Arundel County Extension office 410-222-3900
Class: January 23, 2024

Exam: February 6, 2024

6-8:30 PM Talbot County Ag Center 410-822-1244
Class: February 22, 2024

Exam: February 29, 2024

6-8 PM Carroll County Extension office 410-386-2760
Class: March 7, 2024

Exam: March 14, 2024

1-3 PM Washington County Extension office 301-791-1304
Class: March 19, 2024

Exam: March 26, 2024

9-11 AM Harford County Extension office 410-638-3255
Class: March 19, 2024 8-12 PM Wicomico County Extension office 410-749-6141
Self-paced online Register for the course at: https://umeagfs.teachable.com/p/private-pesticide-applicators-optional-training

 

Nutrient Management Voucher Training
Date Time Location Registration
December 6, 2023 6-8 PM Mt. Airy Volunteer Fire Company 301-600-1594
December 14, 2024 6-9 PM Anne Arundel County Extension office 410-222-3900
February 22, 2024 1-3 PM Harford County Extension office 410-638-3255
February 22, 2024 7-9 PM Washington County Extension office 301-791-1304
March 4, 2024 5:30-7:30 PM Carroll County Extension office 410-386-2760
March 5, 2024 6-9 PM Talbot County Ag Center 410-822-1244
March 12, 2024 6-9 PM Anne Arundel County Extension office 410-222-3900
April 16, 2024 6-8 PM Live training online 410-222-3900

September 2023 Grain Market Update

Dale Johnson, Farm Management Specialist
University of Maryland

Information from USDA WASDE report

Attached is the summary for the September 2023 WASDE.

Corn

This month’s 2023/24 U.S. corn outlook is for slightly larger supplies and ending stocks. Projected beginning stocks for 2023/24 are 5 million bushels lower based on mostly offsetting trade and corn used for ethanol changes for 2022/23. Corn production for 2023/24 is forecast at 15.1 billion bushels, up 23 million from last month as greater harvested area more than offsets a reduction in yield. The national average yield is forecast at 173.8 bushels per acre, down 1.3 bushels. Harvested area for grain is forecast at 87.1 million acres, up 0.8 million. Total U.S. corn use is unchanged at 14.4 billion. With supply rising slightly and use unchanged, ending stocks are up 19 million bushels to 2.2 billion. The season-average corn price received by producers is unchanged at $4.90 per bushel.

Soybeans

U.S. soybean supply and use changes for 2023/24 include lower beginning stocks, production, crush, exports, and ending stocks. Lower beginning stocks reflect an increase for exports in 2022/23. Soybean production is projected at 4.1 billion bushels, down 59 million with higher harvested area offset by a lower yield. Harvested area is raised 0.1 million acres from the August forecast. The soybean yield of 50.1 bushels per acre is down 0.8 bushels from last month. The soybean crush forecast is reduced 10 million bushels and the export forecast is reduced 35 million bushels on lower supplies. Ending stocks are projected at 220 million bushels, down 25 million from last month. The U.S. season-average soybean price is forecast at $12.90 per bushel, up $0.20 from last month. The soybean meal price is unchanged at $380 per short ton and the soybean oil price is raised 1.0 cent to 63.0 cents per pound. Other changes this month include higher peanut and lower cottonseed production.

Wheat

The 2023/24 U.S. all wheat outlook for supply and use is unchanged this month with offsetting by-class changes on exports. The projected 2023/24 season-average farm price is also unchanged at $7.50 per bushel.