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 26, 2018
by Cornell Field Crops
Comments Off on Western Bean Cutworm in New York State

Western Bean Cutworm in New York State

Ken Wise (NYS IPM) and Mike Hunter (CCE North Country Regional Ag Team)

Western bean cutworm (Striacosta albicosta [Smith]) (WBC) was first discovered in New York State in 2009.  It has been expanding its range from its origin in the high plains area of the US over the last 20 years.  WBC is an insect pest of corn and dry beans, and can cause significant yield and quality losses to field corn grain. In other parts of the Corn Belt, it has become a pest causing significant economic losses in field corn.  WBC is a Lepidopteran Noctuidae moth species that lays eggs on the upper surface of leaf just before tasseling (Fig. 1).

Figure 1: Identification of a western bean cutworm moth (Photo by: Adam Sisson, Iowa State University, Bugwood.org)

Figure 2: Eggs are white when first laid (left) and then turn purplish before hatching (Photo by Mike Hunter, CCE)

Once eggs are laid on leaves, they appear white and will turn tan, and then a purplish color before hatching (Fig. 2). The 1st instar larvae will eat their egg shells before finding other food and an area of protection from predators or parasitoids. The small larvae will move to the whorl and/or leaf axil, and they will eat pollen, tassels and silks (Fig. 3). By the 4th instar the larvae will bore into the corn ear and feed on kernels of corn (Fig. 4). One difference between WBC and other species of worm pests of corn ears (European corn borer, corn ear worm) is that you can find multiple worms in one ear. Other species are cannibalistic, and allow only one larvae to enter the ear, while WBC does not mind if there are several per ear.

Figure 3: First instar Western Bean Cutworm larvae (photo by Mike Hunter, CCE)

One to several larvae per ear can really affect the yield. Once the larvae reach the 6th instar they drop from the plant to the soil surface, where they burrow into the soil and create a chamber where they will overwinter in a pre-pupa stage (Fig. 5). They will finish the pupation in late spring and early summer, and emerge from the soil from mid-July through mid-August with peak flights during the last week in July to the first week in August.

Figure 4: Mature Western Bean Cutworm Larvae (Photo by Ken Wise, NYS IPM)

Figure 5: Soil chambers created by western bean cutworm larvae- Photo by Keith Waldron, NYS IPM

Figure 6: Western Bean Cutworm Lifecycle

Since the discovery of western bean cutworm in New York in 2009, we have monitored its progression across the state. In 2010, we developed a WBC pheromone trap monitoring network. This network of Cornell Cooperative Extension Educators, crop consultants and agricultural professionals placed out bucket pheromone traps to capture moths each year from late June through August. A female WBC pheromone lure is placed in the trap which attracts and catches only the male WBC moths. Each week the number of moths are counted and reported by the location of the trap. These traps are deployed to monitor moth presence and determine the peak flight.  Traps help us identify fields at risk and when scouting should take place, but we cannot use trap counts to determine when a field should be sprayed with an insecticide.

Since 2010, the population of the WBC in New York has increased exponentially. We started with 19 volunteers and 44 traps in 29 counties, and in 2018, we had 50 volunteers and 118 traps in 45 counties.

The total number of WBC moths captured per trap in New York by year are depicted in Table 1.  In 2010 there were less than 15 moths caught per trap with a high of 99. In 2018, we had 118 traps that caught 39,290 moths with an average of 333 moths per trap. Some traps in Northern NY had 1000 to almost 3000 moths in a single trap.  Northern NY is the hot spot for WBC, and the number of moths caught in this region of the state far exceeds the rest.

Figure 7: Overall average of WBC moth/trap captures statewide from 2010 to 2018

When looking at the average number of moths caught per trap, 67% of the traps caught more than 100 moths and only 15% caught less than 20 moths (Fig. 7). Jefferson County had a single seasonal trap accumulation of 2964 moths. The range of trap counts were 0 to 2964. While the average came down just a bit from 361/trap in 2017 to 333 /trap in 2018, we had many more traps in areas of the state that do not have the same pest population densities of Northern NY. This brought the average number of moths/trap down for the first time since 2016. In 2016, we had drought conditions that might have caused a reduction in population of WBC.

Figure 8: Average Western Bean Cutworm Moths Caught in Traps Weekly (Includes traps in field corn, sweet corn and dry beans)

A very important aspect of managing WBC is knowing when peak flight occurs.  The annual peak flights are outlined in Figure 8. From 2010 to present, the peak flight has ranged from the last week in July to the first week in August. By knowing the peak flight, you know when most of the moths will be laying eggs in pre-tassel corn because the female moths prefer to lay eggs on this stage of corn growth. And this peak flight time is when we should be vigilant about scouting for WBC egg masses and small larva.

Figure 9: Average Moth Counts/Trap without Northern NY (Includes traps in field corn, sweet corn and dry beans)

The data is starting to show that the population is beginning to build up in areas of the state that have previously had lower populations of WBC. The data in Figure 9 indicates that the average number of moths caught per trap is increasing across the state outside of Northern NY. In time, WBC populations will likely rise across the state to the point that management will be needed for this insect pest. Widespread, high WBC populations in many areas of Northern NY have resulted in some corn fields being treated with insecticides to manage this pest.

While WBC damage to corn ears can be significant and may have detrimental effects on corn grain yield and quality, the economic impact on corn silage is less understood. For corn silage growers, determining whether or not this pest significantly impacts the yield or quality of the forage is critical to their decision making for managing this pest.

Scouting corn at the pre-tassel stage of growth is an important aspect of managing this pest. The economic threshold is 5% of plants having egg masses and small larvae. The 5% is an accumulated threshold, meaning that if in week one 3% of the plants have egg masses and the folowing week there are 2% more, this equals a cumulative 5%.

Current strategies available for control of WBC in corn are the use of foliar insecticides or selecting transgenic corn hybrids with the Vip3A trait.  Foliar insecticide treatments are effective but can be difficult to correctly time applications.  If a field is found to be over threshold for WBC, an insecticide should be applied only if fresh silks are present.  If no tassel is present there is no reason to spray an insecticide because it would be too early and the larva will not survive.  Once the larva make their way into the ear tip it is too late to spray as the insecticide will not come into contact with the larva.  Currently, only corn hybrids with the Vip3A trait will provide control of the WBC.  There have been reports from Michigan, Indiana, Ohio and Ontario, Canada suggesting varying levels of control of WBC with the Bt corn trait containing the Cry1F protein, (DiFonzo, C., Krupke, C., Michel, A., Shields, E., Tilmon, K. and Tooker, J; 2016).  Based on 2016 to 2018 on farm research trials in Northern and Western NY, it was determined that incomplete control from the Cry1F trait was confirmed, (Hunter, M., and O’Neil, K.; 2018, 2017, 2016).

Acknowledgements:
Thank you to Jaime Cumming (NYS IPM) and Marion Zuefle (NYS IPM) for editing and providing additional data for the article.

2018 New York WBC Pheromone Trap Monitoring Network:
Thanks to cooperating growers for allowing us to use their fields for sample sites. Special thanks to the following individuals for their enthusiasm, dedication, excellent data collection and maintenance of the WBC trap network:  Adam Abers, Brian Boerman, Chuck Bornt, Elizabeth Buck, Sara Bull, Paul Cerosaletti, Mike Davis, Janice Degni, Dale Dewing, Natasha Field, Cassidy Fletcher, Jennifer Fimbel, Aaron Gabriel, Kevin Ganoe, Jeffrey Gardner, Don Gasiewicz, John Gibbons, Ethan Grundberg, Mike Kiechle, Ariel Kirk, Jeff Kubeka, George Krul, Christy Hoepting, Mike Hunter, Amy Ivy, Joe Lawrence, Jodi Lynn Letham, Jen Masters, Laura McDermott, Carol MacNeil, Sam Meigs, Stephanie Melancher, Sandy Menasha, Jeff Miller, Anne Mills, Eric Nixon, Kitty O’Neil, Jessica Prospers,  Bruce Reed, Teresa Rusinek, Erik Kocho-Schellenberg, Jack Steele, Abby Seaman, Keith Slocum, Paul Stackowski, Mike Stanyard, Dan Steward, Crystal Stewart, Allie Strun, Linda Underwood, Katherine Vail, Ken Wise, Anastasia Yakaboski, Glenn Yousey, Marion Zuefle, WNYCMA.  The WBC Bt corn trials were made possible with support from both the New York Corn Growers Association and the Northern New York Agricultural Development Program.

References:
DiFonzo, C., Krupke, C.;,Michel, A., Shields, E., Tilmon, K. and Tooker, J; 2016. An open letter to the Seed Industry regarding the efficacy of Cry1F Bt against western bean cutworm. October 2016. Cornell University

Hunter, M., and O’Neil, K.; 2018 Evaluation of the Efficacy of Bt Corn for the Control of Western Bean Cutworm in NNY. Northern NY Agricultural Development Program. Cornell University (report forthcoming)

Hunter, M., and O’Neil, K.; 2017 Evaluation of the Efficacy of Bt Corn for the Control of Western Bean Cutworm in NNY. Northern NY Agricultural Development Program. Cornell University

Hunter, M., and O’Neil, K.; 2016 Evaluation of the Efficacy of Bt Corn for the Control of Western Bean Cutworm in NNY. Northern NY Agricultural Development Program. Cornell University

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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 Impact of Alfalfa Snout Beetle on Dairy Finances in Times of Low Milk Prices

Impact of Alfalfa Snout Beetle on Dairy Finances in Times of Low Milk Prices

Elson Shields, Dept of Entomology – Cornell University, Ithaca, New York

It has been estimated that Alfalfa Snout Beetle costs NNY farmers $445 per cow (or per acre) per year or $44,500 per 100 cows (range $30,000-$60,000), once it has become established on the farm.  The cost estimates are broken down in the following paragraphs.  The Biocontrol Nematode solution to control alfalfa snout beetle currently costs $28 per acre plus application cost.  Research shows a single application provides multiyear control of alfalfa snout beetle. After application, biocontrol nematodes will also reduce the populations of wireworms and corn rootworm when the field is rotated to corn.

Initially, when alfalfa snout beetle move onto a farm, its presence is unnoticed for several years.  The farmer begins to notice a more rapid loss of alfalfa stands, and shortening of alfalfa stand life, requiring more frequent replanting of alfalfa fields or farming them as grass fields.  As ASB moves into additional fields, the farmer gradually begins to purchase more off-farm protein to offset the losses of high quality forages from alfalfa snout beetle.  It is often a decade after the initial infestation of alfalfa snout beetle that the farmer realizes the farm is no longer as profitable as it once was and the causes of this lost profitability is often misidentified.

The true cost of alfalfa snout beetle moving onto the farm can be separated into three distinct areas.  1)  The cost of alfalfa stand loss (stand establishment and loss of yield, 2)  The cost of the off-farm protein to replace the lost forage quality and 3)  Resulting impact on the farm CAFO plan from the increased phosphorus brought on the farm with the increased purchases of protein like soybean meal.  The following cost estimates do not include the impact on the farm CAFO plan.

1)  Cost of Stand Loss from Alfalfa Snout Beetle damage:

With the assistance of Ev Thomas, Oak Point Agronomics, Ltd, Mike Hunter, NNY CCE and Tom Kilcer, Advanced Ag Systems LLC, it was estimated that alfalfa stand loss from alfalfa snout beetle cost the farmer between $200-$400 an acre per year in a three cut 4 yr rotation system and $200-$500 per acre per year in a 4 cut – 3 yr rotation system.  The cost figure is a combination of establishment costs, loss of yield and fixed land costs.  The variation in cost is dependent on the speed of stand elimination by alfalfa snout beetle.  If stand is eliminated in a single year, the higher cost is appropriate and if the stand is eliminated over 2-3 years, the lower cost is appropriate.  A middle of the road figure would be $325 per acre per year.  Using the rule of thumb that one acre of forage feeds a cow for a year, stand losses from alfalfa snout beetle equals $325 per cow per year.

2) Increased Feeding Costs due to loss of high quality forage from Alfalfa Snout Beetle:

With the assistance of Ev Thomas, Oak Point Agronomics and Michael Miller, W.H. Miner Institute, using a diet of 30% forage & 70% corn, the cost of soybean meal to replace the lost alfalfa was estimated to be:

Situation 1:  Clear Seeded Alfalfa is lost and replaced to High Quality Grass (15% CP)

Extra Soy Cost in Diet = $9.30 per cow per month ($111.60 per cow per year).

100 cows = $930 per month or $11,160 per year.

Situation 2:  50% alfalfa and the alfalfa is replaced with High Quality Grass (15% CP)

Extra Soy Cost in Diet = $4.70 per cow per month ($56.40 per cow per year).

100 cows = $470 per month or $5,640 per year.

Situation 3:  Clear Seeded Alfalfa is lost and replaced to Ave Quality Grass (11% CP)

Extra Soy Cost in Diet = $16.80 per cow per month ($201 per cow per year).

100 cows = $2,010 per month or $20,100 per year.

Situation 4:  50% alfalfa and the alfalfa is replaced with Ave Quality Grass (11% CP)

Extra Soy Cost in Diet = $8.40 per cow per month ($100.80 per cow per year).

100 cows = $840 per month or $10,080 per year.

A middle of the road figure would be $10 per cow per month ($120 per cow per year) and 100 cows = $1,000 per cow per month ($12,000 per year) (range $5,640 – $20,100 per 100 cows per year).

This brings the cost of alfalfa snout beetle on the farm to $445 per cow per year (every year) and that cost is broken down in the following manner (Not accounting for the impact on the CAFO plan for the dairy).

Stand and Yield Loss:             $325 per acre (per cow) per year (range $200 – $500)

Extra Soy costs:                      $120 per cow per year (range $56.40 – $201)

Total:                                       $445 per cow per year (every year).

(100 cows  = $44,500, range $30,000 – $60,000)

Control of Alfalfa Snout Beetle with Biocontrol Nematodes:

Research has shown a single application of biocontrol nematodes in a field at a current cost of $28 per acre plus application costs will control alfalfa snout beetle for multiple years.  When the field is rotated into corn, research has also shown impact on wireworms and corn rootworm.  After 4 years of corn, research has shown that the biocontrol nematodes remain in the field at sufficient populations to provide continual control of alfalfa snout beetle.  Even with terrible milk prices a farmer cannot afford not to apply biocontrol nematodes.  (savings = $445 – $28 = $417 per acre (cow) or $41,700 per 100 cows).

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March 9, 2018
by Cornell Field Crops
Comments Off on Western Bean Cutworm and Mycotoxin Screening – 2017 New York and Vermont Corn Silage Hybrid Trials

Western Bean Cutworm and Mycotoxin Screening – 2017 New York and Vermont Corn Silage Hybrid Trials

Joe Lawrence, Gary Bergstrom, Jaime Cummings, Elson Shields, Ken Wise, Mike Hunter

Mold and mycotoxin development in corn ears and the resulting corn silage continues to be a major concern for dairy producers. Mycotoxins can result in a range of problems for livestock throughout the year as they are ingested with the feed. The presence of mold does not always have a strong correlation to mycotoxin development but it does present the chance for incidence to occur.

A number of factors influence the prevalence of molds from year to year. Conducive weather conditions for mold and mycotoxin development are outside the control of management options. But hybrid characteristics and physical damage to the ears can be managed through the selection of hybrids and pest resistance traits in the hybrids.

The presence of Western Bean Cutworm (WBC) in NY corn fields continues to expand as shown in the WBC Pheromone Trap Network coordinated by the NYS IPM program, though the insect’s apparent population varies significantly across the state (Figure 1).

Where WBC populations are high, the corresponding ear damage from WBC feeding can leave wounded corn ears more susceptible to pathogen development, but a clear relationship between ear damage and mycotoxin development has not been documented. A number of mold species may develop on corn ears and a relatively few of these produce mycotoxins. Principal concern in New York is with the mycotoxins deoxynivalenol (DON or vomitoxin) and zearalenone, both produced by the fungus Fusarium graminearum.

While WBC damage to corn ears can be significant and may have detrimental effects on corn grain yield and quality, the economic impact on corn silage is less understood. For corn silage growers, understanding whether or not this pest significantly impacts the yield or quality of the forage is critical to their decision making for managing this pest.

Since the Cry1F protein, which has most commonly been utilized for protection against numerous corn insect pests, has been found to be ineffective against WBC, producers are left with limited management options. Currently the Vip3A trait in select corn hybrids in combination with a scout and spray program is the best option for WBC management in areas where the pest is prevalent.

The Commercial Corn Silage Testing program conducted by Cornell University in collaboration with the University of Vermont and the Northeast dairy industry offers a good opportunity to evaluate numerous hybrids for ear damage from WBC and mycotoxins. This was done in 2017 with support from both the New York Corn Growers Association and the Northern New York Agricultural Development Program.

In 2017, 49 hybrids were selected and planted in replicated plots at two locations in NY (Aurora and Madrid). Each plot was scouted prior to harvest for WBC feeding damage to the ears. Composite samples, of whole plant silage, for each hybrid were taken at harvest and submitted to the Dairy One forage laboratory for a mycotoxin screening package which included aflatoxins B1, B2, G1, G2, vomitoxin, 3-acetyl DON, 15-acetyl DON, zearalenone, and T2 toxin.

The results of the WBC and mycotoxin screening project revealed large differences in the number of hybrids damaged by WBC, but surprisingly few hybrids tested positive for measurable mycotoxins (Table 1).

The most prevalent species of mycotoxin-producing mold found in the screening was Fusarium graminearum which can also infect corn ears through the silk channels at the time of pollination during favorable weather conditions and result in contamination of the grain and silage with the mycotoxins DON, 3-ADON, 15-ADON, or zearalenone. A review of the 2017 weather data at both trial sites showed wet conditions conducive to this type of infection. As expected for New York, no aflatoxins were detected.

While there are numerous ways in which molds can establish themselves in forages, this study reflects a common challenge researchers face while attempting to document the conditions where mycotoxin development is likely. Recognizing that results are specific to the growing season experienced in 2017, which was conducive for silk channel infections. A different relationship between WBC damage and mycotoxin development may be found during a growing season less conducive to silk channel infections. These results from one year of data do not provide strong evidence that WBC damage is a significant concern for corn silage growers who are worried about mycotoxins in their silage. Multiyear studies, including years of varying weather conditions, are required for further evaluating these risks and providing recommendations. It is also important to note that these results do not reflect what may occur in corn harvested for grain as the time between silage harvest and grain harvest offers additional opportunities for infection and growth.

Additionally, there was no correlation between crop yield or starch content with WBC damage in this study. Growers should continue to scout for this pest and weigh the cost of control with the potential for damage.

An article addressing integrated pest management (IPM) practices for WBC has been generated by the NYS IPM team.

Integrated Pest Management for Western Bean Cutworm (Richia albicosta), https://blogs.cornell.edu/ipmwpr/

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