February WASDE

Dale Johnson, Farm Management Specialist
University of Maryland

Information from USDA WASDE report

Attached is a summary for the February WASDE published Tuesday. There was a 50 million bushel increase in the estimate of corn use for ethanol but this increase was offset by a 50 million decrease in the estimate of corn exports and so there was no change in supply, demand or ending stocks.

There was a significant 50 million bushel increase in the estimate for soybean exports. With all other supply and demand factors unchanged this decreased the stocks to use ratio from 11.9% to 10.5%. However, this was anticipated so there was no significant increase in Soybean futures on Tuesday.

There was a 25 million bushel increase in the estimates for wheat exports with all other supply and demand factors unchanged. However with the large ending stocks of wheat, this change was relatively insignificant.

2020 February WASDE

 

Call for Farmer participants in organic grain transitions project

Researchers at the University of Maryland are looking for farmers interested in partnering with them on a project to help develop strategies for transitioning to organic grain production. Please see the attached flier for details. Contact Dr. Ray Weil for additional information (rweil@umd.edu).

Organic Transitions1page announcement Jan2019

At-planting treatments for controlling early-season insect pests in corn

Maria Cramer, Edwin Afful, Galen Dively, and Kelly Hamby
Department of Entomology, University of Maryland

Slug feeding damage: characteristic long, thin holes made by a rasping mouthpart.

Background: Multiple insecticide options are available for early-season corn pest management, including neonicotinoid seed treatments (NSTs) and in-furrow pyrethroids such as Capture LFR®. In addition, many Bt corn hybrids provide protection against seedling foliar pests such as cutworm and armyworm. Given that almost all corn seed is treated with neonicotinoid seed treatments (NSTs), Capture LFR® may not provide any additional protection.

Methods: In this study we compared four treatments: fungicide seed treatments alone; Capture LFR® (active ingredient: bifenthrin) applied in the planting furrow with the fungicide seed treatment; Cruiser Maxx® 250, an NST (active ingredient: thiamethoxam), which includes a fungicide; and Capture LFR® + Cruiser Maxx® 250 together. We evaluated the amount of soil and foliar pest damage after emergence. Yield was measured at harvest.

Preliminary results: Our results suggest that when wireworm pressure is high, Capture LFR® and Cruiser Maxx® 250 protect against damage and significantly increase yields. Neither treatment is superior, so we recommend using only one, and only in fields where pest pressure is known to be high. As most corn seed already contains NSTs, use of Capture LFR® at planting is unlikely to be warranted.

Sampling for soil and foliar pests

Background: Capture LFR®, an in-furrow pyrethroid product, is marketed for control of early-season corn pests, including soil pests such as white grub and wireworm and above-ground pests such as cutworm and armyworm. However, the insect pest management systems already adopted in corn may provide sufficient protection. Most corn seeds are treated with NSTs, which provide seedlings with systemic protection from many soil and above-ground pests. Additionally, most Bt corn hybrids express proteins with efficacy against cutworm and armyworm in the seedling stage, although they do not affect soil pests. Unlike NSTs and Bt traits, pyrethroids are not systemic and do not provide protection beyond the soil area to which they are applied.

While in-furrow applications of bifenthrin (the active ingredient in Capture LFR®) can effectively reduce wireworm damage in potatoes1 and provides white grub control in field corn2,3, it does not consistently increase yield in corn3 or soybeans4. Yield benefits are likely to be seen only where there is known soil pest pressure. Meanwhile, preventative applications of pyrethroids have been linked to declines in natural enemies 5,6, including carabid beetles, which are important predators of slugs.

Objectives: Our objectives were to determine whether in-furrow applications of Capture LFR® (bifenthrin) provided 1) protection against soil pests, 2) protection against seedling pests, and 3) yield benefits compared with fungicide alone, Cruiser Maxx® 250, or combined with Cruiser Maxx® 250.

Methods: This study was conducted in 2018 and 2019 at the University of Maryland research farm in Beltsville, MD. We planted 4 replicate plots of a standard Bt field corn hybrid, TA 758-22DP (VT Double Pro insect control) in 2018 and LC1488 VT2P (SmartStax RIB complete insect control) in 2019 at 29,999 seeds per acre. Plots were planted late in 2018 (June 18) but on time in 2019 (May 20). Standard agronomic growing practices for the region were used. We compared the following four treatments, applied at planting:

  No in-furrow application In-furrow Capture LFR®

Applied at 13.6 fl oz/ac

Fungicide seed treatment Fungicide (F) seed treatment alone

2018: Maxim Quattro®

2019: Vibrance Cinco®

Fungicide +

Capture LFR® (F + Cap)

 

Cruiser Maxx® 250 Cruiser Maxx® 250

(Cru)

Cruiser Maxx® 250 + Capture LFR® (Cru +Cap)

We sampled plants 24 days after planting in 2018, and 18 days after planting in 2019. In 2018, we recorded the number of stunted plants (indicating potential soil pest damage), and in 2019, we dug up stunted plants and recorded those for which soil pest damage could be confirmed. In both years, we assessed rates of above-ground feeding by pests such as cutworm and armyworm.

Wireworm (left) and characteristic above-ground symptoms of wireworm feeding (right). Note wilted center leaf.Results: Soil Pests. In 2018 there was no difference in the percent stunted plants between treatments (Figure 1), with less than 5% stunting in all treatments. This low level of pest damage may have been due to the late planting date, which could have avoided peak soil pest pressure. In 2019, all of the insecticide treatments had significantly lower soil pest damage than the fungicide control (Figure 1). Combining Capture LFR® with Cruiser Maxx® 250 was not more effective than Cruiser Maxx® 250 alone, but was more effective than Capture LFR® alone, suggesting that treatments involving Cruiser Maxx® 250 are somewhat more effective against the soil pests at this farm. In both years, plots were located in a field with a history of wireworms; however, damage was only observed in 2019. In a field without pest pressure, such as we saw in 2018, these treatments did not improve plant stand.

Foliar pests. In both 2018 and 2019, rates of foliar damage were extremely low (below 5% of plants) in all treatments and there were no differences between treatments.

Yield. In 2018, there were no yield differences between the treatments (Figure 2). Overall, we had low yields in 2018, likely a result of the late planting date. In 2019, all of the insecticide treatments had significantly higher yields than the fungicide control, with no differences between any of the insecticide treatments (Figure 2). Combining Capture LFR® with Cruiser Maxx® 250 did not increase yield.

Figure 1. 2018 and 2019 soil pest pressure, Beltsville, MD. Mean percent plants damaged for four treatments: F=Fungicide, F+Cap= Fungicide + Capture LFR®, Cru=Cruiser Maxx® 250, Cru+Cap= Cruiser Maxx® 250 + Capture LFR®. In 2018, treatments did not impact stunted plants (N.S.) In 2019, all insecticide treatments significantly reduced soil pest damage (columns with different letters have significantly different mean damage).
Figure 2. 2018 and 2019 yields, Beltsville, MD. Mean yield for four treatments: F=Fungicide, F+Cap= Fungicide + Capture LFR®, Cru=Cruiser Maxx® 250, Cru+Cap= Cruiser Maxx® 250 + Capture LFR®. Yields were not significantly different in 2018 (N.S). In 2019, all insecticide treatments had significantly higher yield than the fungicide only treatment (columns with different letters have significantly different mean yield).

Conclusions: In 2018 and 2019 we did not see sufficient foliar pest pressure to justify an insecticide application. This may be due to effective control by Bt proteins in the corn hybrids and/or low foliar pest pressure.

In a field with established wireworm pressure, all three insecticide treatments reduced soil pest damage and improved yield relative to a fungicide only control in the 2019 field season. While there were differences in pest damage levels between the different insecticide treatments, no one treatment provided superior yield benefits. Because nearly all corn seed is treated with NSTs like Cruiser Maxx® 250, additional applications of Capture LFR® may not be necessary. Preventative applications increase costs and present risks to beneficial insects without providing yield benefits. Additionally, soil pest pressure tends to be low throughout Maryland. We sampled untreated corn at five locations across Maryland in 2019 and found on average less than 3% soil pest damage. Unless a field has a known history of wireworms or white grubs, we do not recommend using at-planting insecticides.

Acknowledgements and Funding. This project was funded in both years by the Maryland Grain Producers Utilization Board. We appreciate the help provided by Rachel Sanford, Madison Tewey, Eric Crandell, Gabriel Aborisade, and Kevin Conover.

Sources

  1. Langdon, K. W., Colee, J. & Abney, M. R. Observing the effect of soil-applied insecticides on wireworm (coleoptera: Elateridae) behavior and mortality using radiographic imaging. J. Econ. Entomol. 111, 1724–1731 (2018).
  2. Afful, E., Illahi, N. & Hamby, K. Agronomy News. 10, 2–4 (2019).
  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. Koch, R. L., Rich, W. A., Potter, B. D. & Hammond, R. B. Effects on soybean of prophylactic in-furrow application of insecticide and fertilizer in Minnesota and Ohio. Plant Heal. Prog. 17, 59–63 (2016).
  5. Douglas, M. R. & Tooker, J. F. Meta-analysis reveals that seed-applied neonicotinoids and pyrethroids have similar negative effects on abundance of arthropod natural enemies. PeerJ 1–26 (2016). doi:10.7717/peerj.2776
  6. Funayama, K. Influence of pest control pressure on occurrence of ground beetles (Coleoptera: Carabidae) in apple orchards. Appl. Entomol. Zool. 46, 103–110 (2011).

 

Evaluation of the performance of a soy protein seed lubricant

Dr. Nicole Fiorellino, Extension Agronomist
University of Maryland, College Park

With the arrival of a new seed lubricant product (DUST, Low Mu Tech, Calamus, IA), we evaluated its performance against two common seed lubricants, Graphite and Fluency (Bayer Crop Science, USA), and untreated check (UTC) plots in both corn and soybeans in 2019 at Wye Research and Education Center in Queenstown, MD. DUST is a soy protein lubricant and is reported to contribute to early plant vigor as well as be a cleaner alternative to commonly available seed lubricants such as graphite, which can create a mess for users of the product. As such, we utilized a completely randomized design with five replicates and evaluated emergence and early season vigor at 7, 14, and 21 days after planting (DAP). Stand counts were reported as number of 1,000 plants per acre, with plants counted in a 30 ft length of one corn row and plants counted in an area the size of 1/1000 of an acre in soybean plots. Early season vigor was assessed through collection of normalized difference vegetation index (NDVI) readings using a handheld Greenseeker sensor held approximately 1 m from the surface of the ground as the operator walked down the length of one corn or soybean row per plot. Corn was harvested when moisture approached 15% and yields are reported in bushels per acre corrected to 15% moisture.

Differences among seed lubricant treatments for plant population, early season vigor, and crop yield were analyzed using a mixed model analysis of variance using replication as a random variable using SAS 9.4 software. Coefficient of variation (CV%) are reported as a measure of variability at a test site and values less than 10% indicate enough precision existed to determine a significant difference.

Corn

 

Soybeans

 

 

Results

Based on the measurements observed in 2019, the DUST soy protein seed lubricant is comparable to other seed lubricants commonly used in Maryland for corn and soybean planting. There were no differences in emergence or yield among the treatments for either corn, indicating all seed lubricants perform as well as each other and a control plot with no seed lubricant used. Additionally, there was no effect of seed lubricant on early season vigor, as indicated by the company. Additional extension reports will include soybean yield data and economic analysis of the products, as there is a difference in price and amount of product recommended for use and if product performance is similar, as indicated by these results, then product cost will be a deciding factor for use.

2019 Corn Variety Trials Results

Dr. Nicole Fiorellino, Extension Agronomist
University of Maryland, College Park

The University of Maryland offers a fee-based, corn hybrid performance testing program to local and national seed companies. The results from these replicated trials provide agronomic performance information about corn hybrids tested at five locations in Maryland considered representative of the state’s geography and weather conditions. During 2019, 56 hybrids were tested using three maturity groups: early season (17 hybrids), mid-season (14 hybrids), and full season (25 hybrids). Check hybrids were included in each of the five tests.

This year’s weather was welcomed compared to last year’s extreme precipitation. As reported in the results document, there was much less rainfall in 2019, with precipitation at all locations very similar to the long term average for each location. We experienced some drought at the end of summer (August through September in some locations), but yields did not seem to be impacted by this. Averaged over the five locations, yield for early (17), mid (14), and full (25) season hybrids was 196 bu/ac, 199 bu/ac, and 206 bu/ac, respectively. Compared to 2018, these yields were +11%, -1%, and +5%, respectively, to those observed for early, mid, and full season hybrids this season. Average yield for all hybrids tested at all five locations was 201 bu/ac or 10 bushels shy of the record yield of 211 bu/ac in 2011. Two locations had average yield greater than 210 bu/ac (Keedysville – 220 bu/ac and Clarksville – 236 bu/ac) with Clarksville average yield surpassing the record best location yield of 232 bu/ac at attained at Wye in 2016.

A list of hybrids and their performance across the state and at each individual location is presented in the results document, which can be downloaded from the MD Crops website at psla.umd.edu/extension/md-crops. You may also request a printed copy from your local Extension office.

Download the full report here: 2019 Corn Hybrid Trials Results.

 

November WASDE

Dale Johnson, Farm Management Specialist
University of Maryland

Information from USDA November WASDE report

Attached is the summary for the November WASDE published on November 8. After months of volatile WASDE estimates caused by weather and political events, the changes in estimates for the November WASDE are fairly small. Corn yield/acre estimate was down 1.4 bushels/acre to 167 bushels/acre. But the estimates for all areas of demand were also down slightly. The net effect is ending stocks down 19 million bushel to 1,910 million bushel and a stocks to use ratio of 13.7%.

Production and supply estimates for Soybeans were unchanged. Crushings  were down slightly which increase the ending stocks 15 million bushel and a modest increase in the stocks to use ratio to 11.9%.

There were only slight changes in Wheat estimates.

Pyrethroid insecticide effects on pests and beneficials in field corn

Maria Cramer, Edwin Afful, Galen Dively, and Kelly Hamby
Department of Entomology, University of Maryland

Overview

Background: Due to their low cost, pyrethroid insecticides are often applied when other chemical applications are made. For example, they may be included in tank mixes with herbicides in early whorl corn and with fungicides during tasseling. These pyrethroid sprays often target stink bugs; however, the timing of these treatments is not ideal for stink bug management. Pyrethoid insecticides may harm beneficial insects that help keep pest populations in check and repeated use of pyrethroids can contribute to insecticide resistance.

Methods: In this study, we examined the effect of Bifenture EC® (pyrethroid active ingredient: bifenthrin) applied with herbicides in V6 corn and with fungicides in tasseling corn. We evaluated impacts on pests and beneficials at both application timings. Yield was measured at harvest.

Preliminary Results:  At both application timings, Bifenture EC® did not improve insect pest management because pests were not present at economic levels. We did not find evidence for flare-ups of aphids or spider mites, but a rainy late summer made it unlikely that we would see many of these pests. There were no yield differences between the treatments.

Background

As a result of the low cost of pyrethroid insecticides, preventative applications are common, especially in tank mixes with other routine chemical inputs, such as herbicides and fungicides. However, lower grain prices and low insect pest pressure make it less likely that pyrethroid applications will provide economic returns. Bt hybrids1 and neonicotinoid seed treatments control many of the pests targeted by pyrethroid insecticides. Because they have broad spectrum activity, pyrethroids can negatively impact natural enemies2 which can result in flare-ups of secondary pests3. Tank mix timings may be less effective than applying when insect populations reach threshold. For example, when pyrethroids are combined with herbicide applications, they are too late to control early-season stink bugs and other seedling pests. When pyrethroids are combined with fungicide sprays at tasseling, few insect pests are present at damaging levels. Stink bugs may feed on the developing ear at this time, causing deformed “cowhorned” ears; however, this is rarely a problem in Maryland and stink bug damage is generally not economic throughout a field because feeding is primarily concentrated at the field edge4. Insecticide applications at tasseling have a high potential to affect beneficial insects, especially pollinators and natural enemies that are attracted to corn pollen.

Objectives: Our objectives were to determine the effect of pyrethroids applied preventatively in tank-mixes on corn pests, beneficials, and yield.

Methods: This study was conducted in 2018 and 2019 at the University of Maryland research farm in Beltsville, MD. For each application timing, we planted four replicate plots of a standard Bt field corn hybrid, DeKalb 55-84 RIB (SmartStax RIB complete Bt insect control in addition to fungicide and insecticide seed treatments) at 29,999 seeds per acre. Standard agronomic practices for the region were used.

The herbicide timing compared two treatments:

  1. Herbicide alone (22 oz/acre Roundup WeatherMAX®, 0.5 oz/acre Cadet®, 3 lb/acre ammonium sulfate
  2. Herbicide (same as above) + Insecticide (Bifenture EC® 6.4 oz/acre)

Treatments were applied at V6/V7. We visually surveyed corn plants for pest and beneficial insects before and after application. We also placed sentinel European corn borer (ECB) egg masses in the field to assess predation rates before and after treatment.

The fungicide timing compared two treatments:

  1. Fungicide alone (Trivapro® 13.7 oz/acre)
  2. Fungicide (same as above) + Insecticide (Bifenture EC® 6.4 oz/acre)

Treatments were applied at green silk. We inspected the ear zone and silks for pests and beneficial insects before application. After application, we recorded the number of ears with pest damage and the kernel area damaged. We also counted stink bug adults and cowhorned ears. Six weeks after application, we visually assessed plants for spider mite and aphid colonies.

Sampling for pests and beneficials (left) and; sentinel European corn borer egg mass (right).
Sampling for pests and beneficials (left) and; sentinel European corn borer egg mass (right).

Results

In the herbicide-timing study in 2019 we observed no effect on beneficial insects from the treatments (Figure 1). The most abundant beneficial species were minute pirate bugs and pink spotted lady beetles, which are very mobile and may have recolonized treated plots after treatment. Similarly, treatments did not affect predation on the sentinel egg masses, suggesting that the pyrethroid application may not have affected predators’ ability to locate and consume eggs. Across the treatments, 30-50% of egg masses were consumed by predators.

Minute pirate bug on European corn borer egg mass.
Minute pirate bug on European corn borer egg mass.

The treatments did not impact the number of beneficials at the herbicide timing (N.S.). The pyrethroid insecticide significantly reduced the number of plant hoppers and plant bugs from less than 4 per plant on average to less than 2 per plant (significantly different p<0.05, *), though these insects are not economic pests at this stage. There were never more than 2 stink bugs per 90 plants, well below the treatment threshold of 13 per 100 plants4.

In the fungicide-timing study in 2019, beneficials, especially minute pirate bugs, were abundant at the time of application (3 in every 10 plants), while stink bugs, the presumed target pest, were very rare (1 stink bug in every 68 plants). In 2018, stink bugs were similarly scarce. Overall pest abundance was low (1 in every 35 plants). After application, there was no difference in the incidence or amount of the corn ear damaged by worms, stink bugs, or sap beetles between treatments. Average stink bug and earworm incidence was roughly 1 in 10 ears, while sap beetle was even less frequent. Cowhorned ears and adult stink bugs were almost non-existent in both treatments.

Six weeks after application we found no differences in aphid or spider mite populations between the treatments, suggesting that pyrethroid applications at tasseling did not cause secondary pest outbreaks. We sampled after a period of dry weather; however, the late summer was rainy at Beltsville, which likely suppressed spider mite and aphid populations. Under drought-stress, reductions in the natural enemy population from pyrethroid use might contribute to flare-ups of aphids and spider mites.

Figure 1. Herbicide timing. July 3, 2019, Beltsville MD. Mean number of insects per 10 plants in V7 corn after treatment. N.S.=not significant. H=herbicide; P=pyrethroid.

Yield

For the herbicide timing and fungicide-timing (Figure 2) studies, treatments did not affect yields in either 2018 or 2019.

Conclusions

Figure 2. Herbicide timing (left) and fungicide timing (right), 2018 and 2019, Beltsville MD. Mean yield per acre under two treatments. Yields were not significantly different by treatment in either study. For the fungicide-timing study, 2019 yields were significantly higher than in 2018. N.S.=Not Significant. H=Herbicide; F=Fungicide; P=Pyrethroid.

Results from the 2018 and 2019 studies suggest that pyrethroid applications do not provide yield benefits in corn when tank-mixed with herbicides or fungicides, likely due to the lack of insect pest pressure at these spray timings. Beneficial insects were abundant in the crop at each of these timings and did not appear to be affected by the pyrethroids in the herbicide plots. Repeated preventative use of pyrethroids in the same field could potentially hinder the natural biocontrol of corn pests.

Lady beetle larva (a predatory insect) in silks.
Lady beetle larva (a predatory insect) in silks.

Sources

1 DiFonzo, C. 2017. Handy Bt Trait Table for U.S. Corn Production, http://msuent.com/assets/pdf/BtTraitTable15March2017.pdf

2Croft, B.A., M.E. Whalon. 1982. Selective toxicity of pyrethroid insecticides to arthropod natural enemies and pests of agricultural crops. Entomophaga. 27(1): 3-21.

3Reisig, D.C., J.S. Bacheler, D.A. Herbert, T. Kuhar, S. Malone, C. Philips, R. Weisz. 2012.Efficacy and value of prophylactic vs. integrated pest management approaches for management of cereal leaf beetle (Coleoptera: Chrysomelidae) in wheat and ramifications for adoption by growers. J. Econ. Entomol. 105(5): 1612-1619

4Reisig, D.C. 2018. New stink bug thresholds in corn, https://entomology.ces.ncsu.edu/2018/04/new-stink-bug-thresholds-in-corn/

 

Scouting For Stalk Rot In Corn

Alyssa Koehler, Extension Field Crops Pathologist
University of Delaware

We are entering that time of year to begin scouting for stalk rots in corn. Stalk rot signs and symptoms do not appear until later in the season. After pollination, the ear becomes the major sink of sugars produced by the plant. If a stress event occurs, plants will divert or remobilize sugars from the stalk and roots to meet the needs of the developing ear. Often the pathogens that cause stalk rots are opportunistic and take advantage of plants that have been weakened by potential stress events (drought, flooding, hail, insect damage, foliar disease damage). It is also possible to have multiple stalk rot organisms in the same plant.

Yield losses occur when stalks become brittle and lodge close to harvest. Stalk rots can also result in premature plant senescence and reduced grain fill. When plants are a few weeks from physiological maturity (kernel black layer), stalk rots can be scouted by walking the field in a W pattern and randomly checking stalks with either the pinch or push test (aim to check 10-20 plants for every 10-20 acres). For the pinch test, pinch the stalk between the lowest two internodes to see if it can withstand the pressure, if the stalk collapses, it fails. To complete a push test, push the stalk 30 degrees from vertical (around 8 inches) and see how many spring back to upright or lodge. In cases where more than 10% of plants fail the test, you may want to consider harvesting at higher moisture and drying grain after harvest to avoid yield loss due to lodging.

Since stalk rots are linked to stress, the best management strategies are to reduce stress by planting optimal stand populations, irrigating when possible, managing insect pests and foliar diseases, and using a balanced nutritional program. Planting hybrids with some level of foliar disease resistance can also help to reduce plant stress and encourage strong stalk development.

How will this hot, dry weather impact corn yield?

Nicole Fiorellino, Assistant Professor & Extension Agronomist
University of Maryland, Dept. of Plant Science and Landscape Architecture

The conditions this growing season have been a major improvement over the conditions we experienced during the 2018 growing season. Generally, the spring weather was favorable for timely planting of corn on the upper and mid-shore, southern Maryland, and northern Maryland regions, with other regions not lagging far behind. The 2019 growing season has generally been good to us, there was early optimism in the monthly crop reports, but by the end of June, warm and dry weather began around the state. Some areas may have received some spotty thunderstorms throughout July, but the July crop reports indicated droughty conditions throughout the state. As we enter into a new month with minimal precipitation thus far, farmers are concerned about the effects from the prolonged dry and warm conditions on corn yield.

Drought-stressed corn in vegetative growth stage
Drought-stressed corn in vegetative growth stage. Image: A. Kness, University of Maryland.

Warm temperatures and low rainfall cause stress to growing crops and this weather stress can be a major problem prior to pollination, as stress during this stage will impact the potential number of kernels per row. Warm temperatures, specifically, can cause corn plants to utilize more energy to carry out normal functions. Low rainfall can cause corn ear tips to lose kernels. Poor root development, from poor planting conditions and soil compaction early in the season, can amplify the effects of weather stress observed later in the season. But generally, the potential impact on corn yield from warm, dry weather will depend on the maturity of the corn crop when it experiences the weather stress.

Corn is particularly sensitive to weather stress during the late vegetative growth stages when the number of kernels is determined. Four days of weather stress between V12 and V14 could reduce yields 5 to 10%. Even into tassel emergence, total number of kernels can be affected, with yield reduction from 10 to 25% with four days of weather stress at this stage. Silk emergence and pollination is a critical period of moisture use in corn, with weather stress affecting pollination and leading to kernel abortion – four days of stress during silking could reduce yields up to 50%. Generally after pollination, reduced kernel fill can be expected during weather stress, with four days of weather stress post-pollination possibly reducing yields 30 to 40%. During blister and milk stages, kernel abortion is a concern during weather stress, while shallow or unfilled kernels can occur with stress during the dough stage, and reduced kernel weight is a concern during dent.

In summary, there is potential for reduction in corn yield due to the hot, dry weather but the impacts differ based on the maturity of the corn when it experiences the stress. Weather stress during silking and pollination can have the most severe impact on yield potential, with impacts from weather stress decreasing as corn moves further into reproductive maturity.

Sulfoxaflor Registered for New Uses

The U.S. Environmental Protection Agency (EPA) has just issued a long-term approval for the insecticide sulfoxaflor, which the Agency has characterized as “an effective tool to control challenging pests with fewer environmental impacts.” The following information is from today’s EPA OPP Update.

“After conducting an extensive risk analysis, including the review of one of the agency’s largest datasets on the effects of a pesticide on bees, EPA is approving the use of sulfoxaflor on alfalfa, corn, cacao, grains (millet, oats), pineapple, sorghum, teff, teosinte, tree plantations, citrus, cotton, cucurbits (squash, cucumbers, watermelons, some gourds), soybeans, and strawberries.

EPA is providing long-term certainty for U.S. growers to use an important tool to protect crops and avoid potentially significant economic losses, while maintaining strong protection for pollinators,” said Alexandra Dapolito Dunn, assistant administrator for EPA’s Office of Chemical Safety and Pollution Prevention. “Today’s decision shows the agency’s commitment to making decisions that are based on sound science.”

Sulfoxaflor is an important and highly effective tool for growers that targets difficult pests such as sugarcane aphids and tarnished plant bugs, also known as lygus. These pests can damage crops and cause significant economic loss. Additionally, there are few viable alternatives for sulfoxaflor for these pests. In many cases, alternative insecticides may be effective only if applied repeatedly or in a tank mix, whereas sulfoxaflor often requires fewer applications, resulting in less risk to aquatic and terrestrial wildlife.

EPA’s registration also includes updated requirements for product labels, which will include crop-specific restrictions and pollinator protection language.

*Background*

In 2016, following a 2015 decision of the Ninth Circuit Court of Appeals vacating the registration of sulfoxaflor citing inadequate data on the effects on bees, EPA reevaluated the data and approved registrations that did not include crops that attract bees. The 2016 registration allowed fewer uses than the initial registration and included additional interim restrictions on application while new data on bees were being obtained. Today’s action, adding new uses, restoring previous uses, and removing certain application restrictions is backed by substantial data supporting the use of sulfoxaflor.

For additional information, please visit the EPA website.