Cornell Field Crops News

Timely Field Crops information for the New York Agricultural Community

June 17, 2019
by Cornell Field Crops
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NYS IPM Weekly Field Crops Pest Report, June 14, 2019

May 28, 2019
by Cornell Field Crops
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May 20, 2019
by Cornell Field Crops
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NYS IPM Weekly Field Crops Pest Report – May 20, 2019

May 15, 2019
by Cornell Field Crops
Comments Off on Alfalfa Weevil is Slowly Appearing

Alfalfa Weevil is Slowly Appearing

Jaime Cummings and Ken Wise, NYS Integrated Pest Management Program

Alfalfa field

Alfalfa field near Aurora in Cayuga County, May 8. (Photo by J. Cummings, NYS IPM)

Despite this cold, wet spring, which has delayed planting and other farming efforts across NY, our pests and diseases continue to rear their ugly heads.  While the cold had been slowing down some of our insect pests, the alfalfa weevil has been detected in some fields, though currently at low numbers.  This serves as a reminder that we need to continue to be vigilant with our scouting efforts for early detection of pests to make sound management decisions.

Alfalfa weevil

Figure 1. Various instars (growth stages) of the alfalfa weevil larvae, and an adult weevil (Photos by Ken Wise, NYS IPM)

Keep in mind that the alfalfa weevil overwinters in NY and is typically more of a problem in established stands where they emerge in the spring and lay eggs in alfalfa stems.  The larvae cause the most of the damage as they go through four instar growth stages; and the fourth instar causes the most damage (Fig. 1).  Feeding damage from this pest initially looks like small shot-holes in the leaves in the upper canopy, but can quickly progress toward defoliation under high pest pressure (Fig. 2).  During a cold spring, like we are currently experiencing, the alfalfa usually develops faster than the weevils, and we’ll see a delay in weevil emergence and feeding damage.  This year, we are a couple weeks behind when we usually start seeing noticeable damage, and you want to get out scouting now for the weevils and continue to do so weekly through first harvest and early regrowth.

Alfalfa weevil leaf symptoms

Figure 2. Small ‘shot holes’ in leaves are early signs of the pest, which may progress and eventually result in defoliation. (Photos by Ken Wise, NYS IPM)

Scouting for the alfalfa weevil involves walking a random pattern in the field and stopping to collect a stem every 10 steps.  Once you have 10 stems, visually inspect the stems for weevil tip-feeding injury, and count each stem showing tip-feeding injury within the top three inches to determine a percentage of damaged stems.  Repeat this collection of 10 random stems five more times throughout the field for a total of 50 stems inspected.  Repeat this scouting in different patterns within the field weekly.

Follow the established action thresholds based on harvest schedules.  Before first cutting, if 40% of the stems have damage, then management options should be considered.  If approaching threshold, early harvest is a good option.  Otherwise, if you’re unable to manage with an early harvest, and weather permitting, you may consider an insecticide application.  Always consult label instructions and follow Cornell Guidelines for pesticide applications.  Given our ‘late’ spring and late emergence of this pest, an early harvest this year will likely be sufficient for management in fields at high risk or at threshold.  After harvest, always check the regrowth regularly for signs of feeding.  If 50% of the regrowth shows damage and larvae are <3/8” long, then you may need to consider a follow-up insecticide application.  But, keep in mind all factors when considering an insecticide application, including cost, pre-harvest intervals, and weather constraints.  And remember, mixed stands with <50% alfalfa or poor stands of alfalfa should not be sprayed for this pest, because the return on investment is not likely in those situations.  Never spray alfalfa that is in bloom.  Not only is it illegal, but it endangers many pollinators and other beneficial insects.  Keep in mind that at least 13 species of natural biocontrol parasites of this pest exist in NY, and each pesticide application aimed at managing the weevil also kills off your beneficial insects and parasites.  The more beneficial parasites you have, the less likely you’ll have alfalfa weevil issues above threshold.

Alfalfa weevil larva in cocoon

Alfalfa weevil larva in a cocoon, which will emerge as an adult weevil. (Photo by Ken Wise, NYS IPM)

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May 7, 2019
by Cornell Field Crops
Comments Off on Black Cutworm Moths Are Here

Black Cutworm Moths Are Here

Jaime Cummings and Ken Wise, NYS Integrated Pest Management Program

Black cutworm moths in a pheromone trap

Black cutworm moths in a pheromone trap in Tompkins County on May 2 (photo by Jaime Cummings, NYS IPM).

Our statewide network of IPM and CCE staff, along with farmers and crop advisors set out pheromone traps for detecting migration of black cutworms (BCW) the first week of May across the state.   Not surprisingly, based on reports of BCW moths from nearby states in weeks passed, we have received reports of low numbers caught in most traps in the network (Table 1).  However, we’ve heard that some private traps out in western NY have yielded higher numbers.

Numbers of black cutworm moths in pheromone traps in the first week of May

The purpose of this pheromone trapping network is to monitor the arrival of these moths in the state so that we can establish a ‘biofix date’ to start counting growing degree days to help us know when we should expect larval damage in our fields.  Table 2 outlines BCW life cycle and activities based on accumulation of growing degree days.  Note that it takes 90 growing degree days from the time moths arrive to the time the larvae hatch, and it’s the larvae that cause the damage.  See table 3 for growing degree day calculations for select locations.

black cutworm degree daysGrowing degree days for black cutworm

Keep an eye out for BCW larvae in your fields!  And remember, the economic threshold for BCW treatment is reached when 5% or more plants in the stand have been cut or show signs of damage.  The larvae are best controlled when small (< ½”), and soil-applied insecticide rescue treatments at the time of infestation is the most economical and effective management option for BCW infestations.  Lorsban, Pounce and Warrior II all have efficacy against BCW (always consult labels for rates and instructions), and Poncho and Cruiser seed treatments are also labeled for BCW.  Spot treatment is recommended for infested areas of fields, with a 20-40’ surrounding border.  Replant may be necessary if damage is too severe to manage with insecticide.

For updates on the progress of these monitoring efforts, please subscribe to the NYS IPM Weekly Pest Report.

Black cutworm moth

Black cutworm moth (photo by Jaime Cummings, NYS IPM)

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April 26, 2019
by Cornell Field Crops
Comments Off on Black Cutworm and True Armyworm Monitoring Underway in NY

Black Cutworm and True Armyworm Monitoring Underway in NY

By Jaime Cummings and Ken Wise of NYS Integrated Pest Management Program

As black cutworm (BCW) moths have been identified in surrounding states, including Pennsylvania and Indiana, this last week in April marks the traditional timing for deployment of pheromone traps in NY to monitor for BCW moths.  Since 2015, the NYS IPM program has coordinated these statewide monitoring efforts in cooperation with numerous Cornell Cooperative Extension (CCE) educators, farmers and crop advisors.  Since BCW is a migratory pest, which arrives on the winds of storms coming up from southern states, knowing when it reaches NY helps us predict when we need to start monitoring for cutting of corn seedlings by BCW caterpillars.  Scouting for significant populations helps farmers make informed management decisions.  Check newly planted fields every few days for signs of missing, cut or wilted plants, and search for the larvae just below the soil surface near damaged plants (Fig. 1).  The economic threshold for BCW treatment is reached when 5% or more plants in the stand have been cut.  The larvae are best controlled when small (< ½”), and soil-applied insecticide rescue treatments at the time of infestation is the most economical and effective management option for BCW infestations.  Lorsban, Pounce and Warrior II all have efficacy against BCW (always consult labels for rates and instructions), and Poncho and Cruiser seed treatments are also labeled for BCW.  Spot treatment is recommended for infested areas of fields, with a 20-40’ surrounding border.  Replant may be necessary if damage is too severe to manage with insecticide.

Black cutworm larva and damage

Figure 1. Black cutworm larva and damage. (Photos courtesy of Ken Wise, NYS IPM)

True armyworms (TAW), another long-ranged migrant from the south, is an inconsistent early-season pest of corn that we are also monitoring for with pheromone traps this spring.  These moths are attracted to weedy or grassy fields, where they will lay their eggs which will hatch and result in numerous larvae moving into crop fields.  Similar to BCW monitoring, the TAW pheromone traps alert us as to the arrival of these moths so that we can predict when we should be scouting for the damaging larvae.  While out scouting for BCW, you should also be on the lookout for TAW damage, which includes ragged holes and leaf margins and abundant pellet-like frass on and around damaged plants (Fig. 2).  The larvae are often found in the whorls or on the soil surface near damaged plants.  The economic threshold for TAW treatment is when >50% of plants show damage and if you count three or more larvae per plant when corn is in whorl stage or younger.  Older corn can tolerate some feeding, and seldom requires treatment.  Lorsban and Pounce have efficacy against TAW (always consult labels for rates and instructions).  Spot treatment is recommended for infested areas of fields, with a 20-40’ surrounding border.

True armyworm damage and larva with frass.

Figure 2. True armyworm damage and larva with frass. (Photos courtesy of Ken Wise, NYS IPM)

Green bucket trap

Figure 3. The green bucket trap with pheromone lure used to monitor pest migration. (Photo courtesy of Ken Wise, NYS IPM)

2019 marks the 5th year of this statewide pheromone trap monitoring network for these pests in NY, and you may see the telltale green bucket traps in your area (Fig. 3).  This year we have 27 traps each for BCW and TAW in 17 counties, broadly covering all field crop production areas of the state.  Financial support for these efforts comes from USDA-NIFA CPPM, and wouldn’t be possible without the dedicated cooperation of many CCE, farmer and crop consultant collaborators.  Monitoring and scouting for pests leads to sound management decisions and the highest economic return on investment for pest management.  For updates on the progress of these monitoring efforts, please subscribe to the NYS IPM Weekly Pest Report.

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March 26, 2019
by Cornell Field Crops
Comments Off on Expansion of Western Bean Cutworm Trapping Network Helps Protect NNY Crops

Expansion of Western Bean Cutworm Trapping Network Helps Protect NNY Crops

A Western bean cutworm moth nearly hidden in a leaf in a NNY corn crop in the summer of 2018. Photo: Michael E. Hunter

Northern New York is a hotspot for Western bean cutworm (WBC) primarily a pest in field corn, but one that can also impact legume and dry bean crops. With a Northern New York Agricultural Development Program grant, the Cornell Cooperative Extension North Country Region Ag Team expanded the WBC Trapping Network farther into the Northern New York region. Traps were added at locations in Clinton and Essex counties in 2018.

Northern New York trapping sites reported 22 of the highest 25 WBC moth trap catches for the state in 2018.

A report on the expansion of the WBC Trapping Network in Northern New York is posted on the Northern New York Agricultural Development Program website at www.nnyagdev.org.

Data from the traps alerts growers to begin scouting their fields for the risk of WBC and corn ear damage by WBC larvae. Monitoring this pest facilitates early treatment intervention at lower levels of WBC and can help limit crop damage.

The WBC Trapping Network is a program of the New York State Integrated Pest Management Program. Pheremone traps are deployed to capture WBC moths in July and August. The trap catches are identified and counted to help indicate peak flight and fields at risk for WBC damage.

“Because trap counts can vary greatly over just a few miles’ distance, it was determined that placing more traps in Clinton and Essex counties was warranted,” says project leader Kitty O’Neil, Ph.D., a Cornell Cooperative Extension field crops and soils specialist.

“We saw differences from 470 moths in one trap to nearly 2,500, the highest for anywhere in the state, in another trap just 11 miles away one year. Western bean cutworm populations continue to increase in Northern New York, requiring close monitoring and future management of this insect pest to prevent yield and quality losses,” adds Michael E. Hunter, a Cornell Cooperative Extension field crops specialist.

Traps were deployed in 2018 in areas of dense corn production across Northern New York near Beekmantown, Champlain, Chazy, Ellenburg, Ellisburg, Moira, Mooers, North Lawrence, Peru, West Bangor, Westport, and Willsboro.

The traps will be deployed again in 2019. Growers can receive weekly e-bulletins from Extension and the NYSIPM Program.

Funding for the Northern New York Agricultural Development Program is supported by the New York State Senate and administered by the New York State Department of Agriculture and Markets.

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March 21, 2019
by Cornell Field Crops
Comments Off on Corn and Alfalfa Growers: Plan to Apply NNY Nematode Biocontrol Now

Corn and Alfalfa Growers: Plan to Apply NNY Nematode Biocontrol Now

A young farmer applies biocontrol nematodes to his alfalfa field using a farm-made applicator unit in Lewis County. Photo: Joe Lawrence

Northern N.Y., March 20, 2019.  New York corn growers can now reap the benefits of the long-term commitment made by the farmer-driven Northern New York Agricultural Development Program (NNYADP) to the research needed for managing the most destructive alfalfa crop pest. Not only does the science-built biocontrol nematode protocol significantly reduce alfalfa snout beetle populations, it also has shown management capacity for dealing with corn rootworm, wireworm, and white grubs.

“We are confident that dairy farmers who inoculate their fields with these biocontrol nematodes for management of alfalfa snout beetle or corn rootworm are also benefitting from reduced populations of wireworms and white grub insects,” Cornell University entomologist Elson Shields, Ph.D., Ithaca, N.Y., said.

The successful biocontrol nematode protocol developed by Shields and research technical Antonio Testa is now being applied to multiple crops in New York State and in multiple states.

More than 500,000 acres in New York State are known to have alfalfa snout beetle infestation. Shields’ research team estimates the total cost of alfalfa snout beetle left untreated on a farm  ranges from $300 to $600 per cow. The one-time cost of applying the biocontrol nematodes is approximately $30 per acre, plus any application costs.

Farmers interested in applying the biocontrol nematodes through the Shields Lab rearing program at Cornell have only a three-year window to do so. It requires three to five years to totally inoculate a farm to significantly reduce the alfalfa snout beetle populations. The Shields Lab will stop rearing the nematodes as part of its research program in 2021.

For more information on purchasing the biocontrol nematodes and information on proper application methods, growers should contact the Shields Lab at least 45 days prior to a planned application. Contact Tony Testa at 607-591-1493 or at28@cornell.edu. Farmers can also work through Cornell Cooperative Extension Field Crops Specialists Kitty O’Neil and Mike Hunter, and Doug Zehr with the Lowville Farmers Co-Op.

Farmers interested in applying the biocontrol nematodes for corn rootworm management may be eligible to participate in a Northeast Sustainable Agriculture and Research Education grant for the next three years to receive reduced biocontrol nematode pricing on a limited basis. For more information, contact Mike Hunter at 315-788-8450 or Tony Testa at 607-591-1493 for details.

Research has shown that a single application of the biocontrol nematodes can persist for 10 years across an alfalfa-corn rotation and that the nematode population was higher after four years of corn than in alfalfa before the corn planting.

Since 2010, more than 20,000 acres of alfalfa in Northern New York have received a biocontrol nematode application.  At least one new nematode-rearing business enterprise was started as a result of the NNYADP-funded research and technical training on the biocontrol nematodes. Custom applicators in the region have also provided nematode application services.

The Shields Lab is available to work with anyone who would like to develop a business enterprise to supply nematodes to custom applicators or to farmers who wish to apply them on their own.

The NNYADP website at www.nnyagdev.org includes Shields’ research reports on development of the alfalfa snout beetle biocontrol solution, the results of NNYADP-funded field and laboratory trials developing alfalfa snout beetle-resistant alfalfa varieties, and more recent studies of the impact of the biocontrol nematodes on corn rootworm and on applying the biocontrol nematodes in liquid manure.

Funding for the Northern New York Agricultural Development Program is supported by the New York State Senate and administered by the New York State Department of Agriculture and Markets.

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September 4, 2018
by Cornell Field Crops
Comments Off on NYS IPM Weekly Field Crops Pest Report: August 31, 2018

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