What's Cropping Up? Blog

Articles from the bi-monthly Cornell Field Crops newsletter

October 4, 2018
by Cornell Field Crops
Comments Off on What’s Cropping Up? Volume 28, Number 4 – September/August 2018

What’s Cropping Up? Volume 28, Number 4 – September/August 2018

September 28, 2018
by Cornell Field Crops
Comments Off on Apologies for the repeated emails

An issue with the blog management system caused repeated emails to be sent of our weekly new post digest. Subscriber emails have been disabled, and we are working with IT to determine the cause and resolve it for the future. Thank you for understanding.

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September 25, 2018
by Cornell Field Crops
Comments Off on Growing GMO free corn: Insect management challenges revisited from the pre-GMO era

Growing GMO free corn: Insect management challenges revisited from the pre-GMO era

Elson Shields – Entomology, Cornell University, Ithaca, NY

Seed Treatments:

Seed treatments on corn seed is a critical component to achieve a uniform plant stand, particularly in cropping systems with animal manures such as our dairy farms.  Without a uniform plant stand, economic yields are always a challenge.  In some situations, seedling insects are shown to reduce plant stand by more than 50%.  For the 2019 growing season, it appears that our use of neonic seed treatments are not threatened.  Neonic seed treatments are effective against the two main seedling insect pest, seed corn maggot and wireworm.  Activity against Black Cutworm larvae is variable at best.  The standard “250” seed treatment dose is effective against the seedling insects listed above but not corn rootworm.  For activity on corn rootworm, the “1250” dose needs to be used.  A new class of compounds called Anthranilic diamides are being tested as replacements to the neonic seed treatments.  These compounds work well on Seed Corn Maggot, but are weak on wireworms.

Black Cutworm:

Black Cutworm is a long-ranged spring migrant which rides the warm southern spring winds into NY between late-March and mid-April.  Upon arrival, moths lay their eggs on grassy weeds in the field before the corn is planted.  When these weeds are killed by tillage or herbicide, the larvae continue to feed on the dying tissue until the planted corn emerges and then moves over to the corn.  It is important to remember that Black Cutworm larvae are in the field before corn planting and the larvae are usually early-mid-sized when the corn emerges.  If the eggs were actually laid in the emerging corn, the developing corn would grow to V6 before the black cutworm larvae developed into the 4 instar where they begin cutting. V6 corn is very resistant to being cut by Black Cutworm.

Insecticide on the seed is often promoted to have Black Cutworm control properties, but control is highly variable and dependent on moisture conditions.  Field scouting is the only dependable and reliable method to detect Black Cutworm infestations and treat them before economic loses occur.  Smaller larvae feed on leaf margins leaving ragged leaves and do not begin cutting until the fourth larval stage.  A trained scout can easily detect these larvae before cutting and recommend a timely application of a foliar insecticide to prevent damage.  The threshold for treating a corn stand for Black Cutworm is 5% or more of the plants cut.

Armyworm:

Armyworm is a long-ranged spring migrant which rides the warm southern spring winds into NY between mid-May and early-June.  Upon arrival, moths lay their eggs in grass hay fields and other grassy areas.  When those areas are stripped from feeding by the larvae, the larvae “march” into neighboring field which are often corn.  Scouting is the only reliable way to detect this insect and monitor its movement into adjacent corn.  The threshold for treatment in whorl sized plants is 3-larvae per plant with feeding damage present.

Corn Borer:

European corn borer before the GMO era was never an economic pest in NY field corn.  While it could be found in almost every field, populations needed to be one larva in every plant before any economic impact could be measured.  Reported infestations were never close to that population.  With the introduction of corn borer-GMO corn varieties, the corn borer populations have fallen to an extremely low level and are not expected to poise any threat to the corn producer growing non-GMO corn.

Corn Rootworm:

Western corn rootworm remains the primary major insect pest of corn production, costing US corn farmers nearly $1 billion to control it.  In NY, first year corn never has any problem with corn rootworm damage because the current NY strain of corn rootworm only lays its eggs in existing corn fields.  Corn producers who annually rotate between corn and a non-corn crop do not need to deploy any management strategy for corn rootworm control.  Corn producers who grow corn in a field for more than a single year are the producers who need to pay attention to the various corn rootworm management options.  Generally speaking, the longer a field is in continuous corn production, the higher the risk from corn rootworm larval feeding injury and economic losses.  For example, a 2nd year corn field generally has about a 25% risk for an economic infestation of corn rootworm and a 4th year corn field has 80-100% risk.

Scouting:     Adult scouting protocols are well tested and are useful in predicting the probability of a corn rootworm infestation the following spring.  Adult rootworms are counted on three consecutive weeks starting around pollen shed.  If the average adult beetle count is 1 beetle/plant for the 3 week period, the field is usually at risk the following year from corn rootworm feeding injury.  More information can be found at the following link:

https://nysipm.cornell.edu/sites/nysipm.cornell.edu/files/shared/field-corn-scouting-proc.pdf

Management options:     The non-GMO corn producer only has two viable options to manage corn rootworm in continuous corn in years 2-6.  Best control is the use of a granular insecticide in a T-band in front of the press wheel.  An in-furrow application of a granular insecticide has a much lower efficacy than the T-band.  Calibration of the granular insecticide applicators is important for good corn rootworm control.  However, many producers no longer have granular boxes on their corn planters and the use of granular insecticides at planting is no longer an option.  The only other option with some level of efficacy is the high rate of seed treatment on the seed (1250 rate).  Often, this treatment fails under high corn rootworm larval pressure or wet growing seasons particularly in the months of May and June.

The use of liquid insecticide in the liquid popup fertilizer at planting has become a popular option and is pushed very hard by the various pesticide industry sales people.  Unfortunately, this insecticide application is seldom successful in protecting the corn roots from corn rootworm larval feeding.

Western Bean Cutworm:

Western Bean Cutworm (WBC) has become an emerging challenge for the corn producer in NYS with the heaviest populations along Lake Ontario in WNY and across NNY.  Previous larval control with Cry1F incorporated into the plant has increasingly failed to control the larvae.  In the production of GMO-free corn, management of WBC becomes an important issue to be aware of.  The larvae feed on the developing ear after pollination.  The threat to the corn producer is both yield loss and mycotoxin contamination.  Ingress and feeding by the WBC larvae opens the developing ear to increased infection by mycotoxin-producing fungi.  At this point in time, the threat of high levels of mycotoxin in the harvested grain and chopped silage is the bigger issue than kernel/yield loss.

Scouting:     Use of pheromone traps to time scouting efforts is recommended. Moth flight begins about the last week of June, so traps should be in place by mid-June and should be checked weekly. Scouting should begin when multiple moths are being captured with frequency.  Monitoring efforts should be focused upon fields that are just beginning to, or soon will, shed pollen. Fields past pollen shed are less attractive to the female moths to lay eggs.

Scout plants by examining the upper surfaces of new and not-yet unfolded leaves of plants in multiple areas of the field. 20 consecutive plants in at least 5 locations are suggested as a minimum. Infestations are very patchy, and oviposition occurs over several weeks so multiple field visits will be required. Upper leaf axils, tassels (before pollen shed), and silks should be examined as well for young larvae. Monitoring and early detection are critical for application of foliar insecticides. There is a suite of insecticides that will kill young larvae, but ensuring they receive a lethal dose before entering the ear is difficult.

Economic threshold:     When 5% of the plants have egg masses or small larvae and 90-95% of the tassels have emerged, treatment is recommended. If tassels have already emerged and egg hatch is underway, applications should occur when 70-90% of eggs have hatched. Larvae must encounter insecticide or residue before entering the ear – once they enter the ear insecticide applications are not as likely to contact larvae, making control difficult.

 

 

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August 7, 2018
by Cornell Field Crops
Comments Off on What’s Cropping Up? Volume 28, Number 3 – July/August 2018

What’s Cropping Up? Volume 28, Number 3 – July/August 2018

July 23, 2018
by Cornell Field Crops
Comments Off on Another Shocker: Organic Wheat with High Inputs 86 Bu/Acre Vs.79 Bu/Acre for Conventional Wheat (both yield 80 bushels/acre with recommended inputs)

Another Shocker: Organic Wheat with High Inputs 86 Bu/Acre Vs.79 Bu/Acre for Conventional Wheat (both yield 80 bushels/acre with recommended inputs)

Bill Cox, Eric Sandsted, and Phil Atkins

Conventional wheat with recommended inputs (on the right), despite more yellowing of the leaves in the lower canopy in mid-June, yielded similarly (~80 bushels/acre) as high input conventional wheat (on the left).

We initiated a 4-year study at the Aurora Research Farm in 2015 to compare the corn, soybean, and wheat/red clover rotation with different crop sequences in conventional and organic cropping systems during the 36-month transition and early certification period to an organic cropping system. One of the many objectives of the study was to determine if corn, soybean, and wheat respond similarly to management inputs (high and recommended) in conventional and organic cropping systems. This article will discuss the agronomic performance of organic wheat and conventional wheat with recommended and high inputs in the 4th year of the study (red clover-corn-soybean-wheat/red clover).

We no-tilled a treated (insecticide/fungicide seed treatment) Pioneer soft red wheat variety, 25R46, in the conventional cropping system; and the untreated 25R46 in the organic cropping system at two seeding rates, ~1.2 million seeds/acre (recommended input) and ~1.7 million seeds/acre (high input treatment) with a John Deere 1590 No-Till Grain Drill (7.5 inch spacing between drills) on September 27, the day after soybean harvest. We applied about 200 lbs. /acre of 10-20-20 as a starter fertilizer to wheat in both conventional treatments. We also applied Harmony Extra (~0.75 oz. /acre) to the high input conventional treatment at early tillering or GS 2 stage in the fall (October 27) for control of winter perennials (dandelion in particular).

Organic compared with conventional wheat yielded similarly (recommended inputs) or 9% higher (high inputs) at the Aurora Research Farm in 2018.

We applied the maximum amount of Kreher’s composted chicken manure (5-4-3 analysis) that would flow through the drill as a starter fertilizer (~150 lbs. of material/acre) in both organic treatments. We also broadcast Kreher’s composted manure the day after planting  to provide ~50 lbs. of actual N /acre (assuming 50% available N from the composted manure) in the high input treatment of the organic cropping system. In addition, we also added Sabrex, an organic seed treatment with Tricoderma strains, to the seed hopper of 25R46 in the high input treatment in the organic cropping system.

We frost-seeded red clover into all the wheat treatments on March 22. We applied ~70 lbs. of actual N/acre (33-0-0, ammonium nitrate) in the recommended input treatment of conventional wheat on March 23, about a week before green-up. In the high input conventional treatment, we applied ~50 lbs. of actual N/acre (33-0-0) on March 23 and then applied another 50 lbs. of actual N/acre on April 26 about 10 days before the jointing stage (GS 6). We also applied a fungicide (Prosaro at 4 oz. /acre) to the high input treatment on May 30.

We applied Kreher’s composted chicken manure to provide ~70 lbs. of available N/acre to organic wheat in the recommended input treatment on March 21. Also, we applied an additional ~50 lbs. of available N/acre to organic wheat in the high input treatment on March 21. All the plots were harvested with an Almaco plot combine on July 10. We collected a 1000 gram from each plot to determine kernel moisture and grain N% in the laboratory.

We presented data on wheat emergence as well as wheat densities and weed densities in the fall (http://blogs.cornell.edu/whatscroppingup/2017/12/01/organic-compared-with-conventional-wheat-once-again-has-more-rapid-emergence-greater-early-season-plant-densities-and-fewer-fall-weeds-when-following-soybean-in-no-till-conditions/) and weed densities in the early spring (http://blogs.cornell.edu/whatscroppingup/2018/05/25/no-till-organic-wheat-continues-to-have-low-weed-densities-in-early-spring-april-9-at-the-tillering-stage-gs-2-3/) in previous news articles. Briefly, organic wheat had more plants/acre, and similar weed densities in the fall and spring (Table 1). This is the second time that organic compared to conventional wheat no-tilled into soybean stubble had better stands and very low weed densities. Organic growers who harvest soybean fields with low winter weed pressure (dandelion, mallow, chickweed, henbit, mayweed, etc.) should consider no-tilling organic wheat, especially if the soybean field had been moldboard plowed. If soybeans were no-tilled into roller-crimped rye in early June, the rye residue could harbor significant slug/snail populations during the cool and damp fall mornings, which could impact wheat stands.

A cropping system x management input interaction was observed for wheat yield in 2018 (Table 2). Organic and conventional wheat yielded 80 bushels/acre with recommended inputs in 2018. Organic wheat showed a 6 bushel/acre response to high input management (500,000 more seeds/acre and an additional 30 lbs. of N/acre). In contrast, conventional wheat did not respond to high input management, despite 500,000 more seeds/acre, a fall herbicide application, 30 lbs. more N/acre, and a fungicide application. Once again, conventional wheat did not respond to the “new way” of managing wheat, high input wheat, which is similar to results that we have observed in all years with dry springs when we compared high and recommended input wheat in the 1980s and 2000s. Obviously, there is no need to apply additional N or apply a fungicide to wheat during dry springs because fertilizer N applied in late March or early April will not be lost to the environment via leaching or denitrification and disease pressure is low.

In 2016, a year with very similar precipitation patterns to 2018 (5.88 inches vs. 6.5 inches of precipitation, respectively, from April 1 through June 30), organic wheat yielded ~7.5% lower than conventional wheat when averaged across input treatments with no response to high input treatments in either cropping system(http://blogs.cornell.edu/whatscroppingup/2016/09/26/organic-wheat-looked-great-but-yielded-7-5-less-than-conventional-wheat-in-20152016/). Temperatures in May when N demand by wheat is the highest, averaged 62.0o in 2018 but only 56.5o in 2016. Cool temperatures limit N mineralization from organic sources so in 2016 we speculated that the use of an organic N source may have resulted in less available N to the organic wheat crop. Indeed, grain N% concentration in organic (1.66%) vs. conventional wheat (2.03%) was much lower in 2016 lending credence to the lack of available N as the major factor in the lower organic wheat yields. In 2018, conventional compared with organic wheat once again had greater grain N% concentration (1.99% vs. 1.77%, respectively, Table 2) but the difference was not as vast. Evidently, the warm May conditions allowed for release of adequate N from Kreher’s composted manure to maximize yields. May of 2018, however, was the second warmest on record in central and western NY. In years with cool late April and May conditions, organic wheat production may face N availability challenges because of low mineralization rates of organic N sources.

In conclusion, organic wheat yielded the same as conventional wheat with recommended inputs and yielded 9% greater than conventional wheat with high inputs. Kreher’s composted chicken manure, however, is very expensive (~$300/ton with only 5% N analysis of which we assumed only 50% N availability) so N costs approximated $6/lb. of N or ~12x higher than the ammonium nitrate source for conventional wheat. Consequently, organic compared with conventional wheat with recommended inputs probably had lower returns in 2018, despite being eligible for the organic price premium in the 4th year of this study (we will conduct a complete economic analysis of this 4-year study in late fall or spring of next year). Organic wheat with high inputs probably had similar economic returns as conventional wheat with high inputs, a common practice among some NY wheat growers, because the 12x higher cost for N in organic wheat would be offset by the higher cost for treated seed, fall herbicide application, the second N application, and late spring fungicide application in high input conventional wheat. Most organic wheat growers, however, probably use a dry solid manure source that is far less expensive than Kreher’s composted chicken manure so the economic analyses in this study will be slanted against organic wheat. On the other hand, the use of dry solid manure is far more difficult to apply precisely and at the correct time to insure availability to the wheat crop in May during stem elongation so the yield data may be slanted towards wheat in this study.

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June 6, 2018
by Cornell Field Crops
Comments Off on What’s Cropping Up? Vol. 28 No. 2 – May/June 2018

What’s Cropping Up? Vol. 28 No. 2 – May/June 2018

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