May 29, 2014

NYS IPM Weekly Field Crops Pest Report, May 29, 2104

Volume 13  Number 3


View from the Field

Purdue University in Indiana states the true armyworm moth flights have been moderate but they are finding larvae active in annual rye cover crop fields and weedy no-till fields. They suggest these fields might be at higher risk of having armyworm damage corn.  Penn State indicates they have had high black cutworm flight captures this year. They are suggesting to their farmers to get out and scout for black cutworm.

Mike Stanyard (CCE, WNY Field Crop Team) reports that cereal leaf beetle on oats in some fields were at threshold this week. Mike indicates that there was lot of slug damage on no-till corn. He said they were both gray and black slugs. Some farmers have sprayed for the slugs on corn this spring. He has also found some powdery mildew on wheat.

Bill Verbeten (CCE, WNY Field Crop Team) reports finding some populations of cereal leaf beetles on oats and winter wheat. He found alfalfa weevil larvae in alfalfa fields. He suggests farmers will be spaying fungicides on winter barley within the week.

Keith Waldron (NYS IPM) reports alfalfa weevil tip feeding damage in Geneva with larvae between 2nd and 3rd instars.

Ken Wise (NYS IPM) found more cereal beetle larvae this week on the triticale trials at the Cornell University Research Farm in Valatie. There was less than one larva per tiller. He also discovered 1st through 3rd instar alfalfa weevil larvae at the farm. The alfalfa was showing less than 5% alfalfa weevil damage. The alfalfa and clover were 18 to 20 inches.

Turf consultant Rod Ferrentino (Ferrentino & Co Inc.) reports finding 3/8 inch black cutworm larvae in sod in the Syracuse area.

Weather Outlook – May 29, 2014

NOAA Northeast Regional Climate Center, Cornell University

Jessica Spaccio (Rennells)

Last week temperatures ranged from 0 to 6 degrees above normal. Precipitation ranged from just a trace to 2 inches for most areas, with storms brining 3 to 4 inches to isolated areas.  Base 50 growing degree-days ranged from 40 to 100, less than 40 in the Adirondack region. Another nice weekend ahead, unsettled weather Monday through Wednesday with locally heavy rain possible. Today will be partly cloudy with temperatures in the mid 60’s to low 70’s.  Scattered showers are possible overnight into Friday as a week cold front moves across the state; lows in the mid to upper 40’s. Friday will be cloudy with a change for showers and thunderstorms – mostly east of Interstate 81, western NY will be warm and dry; highs in the mid 60’s to mid 70’s.  Overnight temperatures will be in the mid 40’s to low 50’s. Saturday will be mostly sunny, breezy and dry for most areas, a few lingering showers in eastern NY; highs in the mid 60’s to mid 70’s.   Lows will be in the 40’s to low 50’s. Sunday will be partly sunny and warmer with highs in the mid 70’s to low 80’s.  Lows will be in the mid 50’s to low 60’s. Monday’s highs will be in the upper 70’s to low 80’s.  A front will bring the chance of showers and thunderstorms.  Lows will be in the mid 50’s to low 60’s. Tuesday will be in the mid 70’s and low 80’s with a continued chance of showers and thunderstorms.  Lows will be in the low to mid 60’s. Wednesday’s highs will be in the mid 70’s to near 80 with showers likely.  Lows will be in the upper 50’s to low 60’s. The five-day precipitation amounts will range from .10 to 0.5 inch; 7-day amounts will range from ¾” to 1 ¼”. The 8-14 day outlook (Jun 5-11) is showing above normal temperatures for the entire state and above normal precipitation for western NY and south central NY.

Maps of 8-14 day outlooks

National Weather Service watch/warnings map

NRCC Drought Page which features the US Drought Monitor map (updated every Thursday)

Have Dairy Cattle? Have Barn Flies?

It’s early in the summer season but not too early to gear up for managing house and stable flies the two most common fly pests in and around dairy facilities. These flies breed in moist organic matter. Add the wet weather we’ve had this season to any spilled feed, straw bedding and other undisturbed organic matter and you have the makings of great fly breeding habitat and a potential barn fly problem. Our relatively cool temperatures so far this season have helped to slow down fly development but add some warm days and if you’ve got the right habitat you just may start to notice more flies around the barns.

The good news is that early intervention can help minimize 90% or so of the potential fly problem. A little management time each week will pay big dividends as the season progresses. The two most common fly species found in barn areas are the house fly and stable fly. Both fly species prefer to lay their eggs in moist, not wet, moist organic matter such as spilled feed, moist hay, wet grain, and straw bedding. These areas are great habitats for maggots to develop leading to populations of these nuisance flies.

Keeping things dry has certainly been a challenge this season, however, efforts to keep potential fly breeding habitats as dry as possible are important to minimize fly issues and help protect animal health. When temperatures average 68 F the house fly can grow from egg to adult in 18-21 days. At higher temperatures, say 86° F, development speeds up considerably, taking only 9 – 11 days to go from egg to an adult fly. Take home message? If fly breeding conditions are favorable and it get’s warmer, the fly situation on farms can change quickly and dramatically. Here are a few tips to help avoid fly population surprises and potential problems.

Keep it dry. Check water sources for leakage, check rain gutters and outside water diversions for effectiveness, if water buckets are used with animals, such as in a calf pen, empty water buckets away from the animals and animal bedding

Sanitation, Sanitation, Sanitation! Staying ahead of fly populations begins with cultural practices that eliminate conditions favorable to fly breeding. House flies and stable flies both breed in areas where moist undisturbed organic matter such as spilled feed and manure-soiled bedding are present. Another favorable breeding spot is a location that remains relatively undisturbed and offers protection from foot and hoof traffic. Frequent clean out of these favorable breeding habitats and other activities that enhance dry conditions in animal areas will make the local environment inhospitable to successful buildup of fly populations. Removing fly breeding habitat frequently, daily if possible, or at least once or twice a week at a minimum.

Choice of animal bedding material. This time of year many farms are transitioning from winter bedding choices such as straw to summer bedding choices. Studies have shown the more easily bedding can stay dry – i.e. better drainage, the less hospitable it is for fly populations to develop. Substituting sand, gravel, wood chips/shavings or sawdust bedding over straw, especially for calf pens, has been shown to significantly reduce house and stable fly maggot populations, but may not always be economical or practical. If straw is used, keep it dry, change bedding frequently – at least once per week, check areas that are not disturbed, such as corners, under head locks, near water and feed sources, for signs of fly larvae.

Protect Natural Enemies. A variety of biological control agents occur naturally in the typical dairy barn. These include various predators of house and stable fly eggs, larvae and adults. When sanitation is used effectively, natural enemies can more easily keep up with remaining fly populations and can be quite effective at reducing their numbers. The key is to employ sound sanitation, early and as often as practical, as the first line of defense for mitigating fly populations. Common fly predators include predaceous mites, rove and Carcinops beetles, parasitoid wasps, and fly diseases. Parasitoids, the small wasps that attack fly pupae, are quite effective at reducing fly populations. These tiny wasps, however, can take up to three times longer to develop than the house fly. This is the reason their populations can use a “jump start” early in the season to reach the numbers needed to head off house fly problems. For those wishing to use parasitoids to enhance their biological control efforts, the earlier in the season releases can begin the better. There is still time to begin releasing the wasps in barns and calf housing areas. Parasitoids should be released close to their prey, i.e. in and around potential fly breeding habitat. Cornell research has shown the dairy fly parasitoids (Muscidifurax raptor and Musicifurax raptorellus) to be the most effective fly predators for use in dairy facilities in New York.

Reducing the number of adult (breeding) flies helps minimize the potential for fly population buildup.

Sticky Situations. Two additional fly management tactics to curb fly numbers include use of sticky ribbons, tapes, fly string on a reel and insecticide baits. Sticky ribbons (including the wide roll types) and tapes on a reel offer an effective non-toxic means to capture adult flies. Place sticky tapes in areas not at risk from high winds, turbulent air and dusty conditions, Insecticide : sugar bait stations can also be deployed to capture adult flies removing them from the breeding population.

For more information on IPM for barn fly management see: Integrated Management of Flies in and around Dairy and Livestock Barns,  IPM Guide for Organic Dairies  and  IPM livestock videos 


Alfalfa Weevil Scouting

Ken Wise-NYS IPM

Alfalfa weevil can be a problem for established alfalfa fields prior to and shortly after first harvest.  To avoid unnecessary losses associated with injury from this insect pest begin monitoring fields in mid to late April when growing degree days have reached about 280 GDD (base 48F). The monitoring process is very straight forward. Look for signs of weevil feeding as holes in leaves and leaf buds and assessing the percentage of leaves affected. Here’s how:

  • Pick 50 alfalfa stems at random throughout the field.
  • Look for the small “shot holes” in the leaves that indicate that larvae are feeding.
  • Record the percentage of alfalfa stems that show the “shot hole” feeding damage in the top 3 inches of the canopy.


Alfalfa Weevil Larvae Damage

Alfalfa Weevil Larvae Damage

Alfalfa Weevil Tip Larval Feeding

Before the first cutting, if 40% of the stem tips show feeding damage, you are at the “action threshold”. The good thing is that alfalfa weevil can generally be controlled by harvesting. If you reach an action threshold within a week of your normal 1st cutting date, early harvesting will help avoid economic, yield, and forage quality losses. Alfalfa weevils only have one generation per year and are typically not a problem after first harvest. Occasionally, weevil can damage alfalfa re-growth after harvest. This damage may be more evident in the windrow areas, and can be more noticeable under cool or droughty weather conditions. If you find that 50 percent of the new growth is damaged, with many small larvae present, a chemical control may be warranted. For more information on alfalfa weevil checkout our online publication: IPM for Alfalfa Weevil

Wet Spring Season Corn Pests: Diseases, Slugs and Maggots 

Ken Wise, NYS IPM

Wet spring….! Wet cool springs have potential problems for corn planted into wet soil. Since the temperature is cool the soil temperature is also lower than normal. Once seed is planted it will not emerge quickly. The longer the seed stays in the ground the chance of getting seed decay or seedling diseases increases. Early season corn seed and seedling diseases can reduce plant populations, thus reducing yields. Some expected yield losses can range from about 5% to 10%. If your average silage harvest is 20 tons/acre, a 10% loss in yield would be 2 tons/acre. The following is how to identify early season seed and seedling diseases. Seed decay is caused by a number of soil-inhabiting fungi such as Pythium, Fusarium, Diplodia, Rhizoctonia and Penicillium. The fungi can infect seed before it germinates causing mortality. Seeds infected with decay fungi are discolored and soft. Many times fungal material may grow on the seed. Often when the seed has rotted it may be completely decomposed and cannot be found. Sometimes the seed may germinate and grow but will die as the plant emerges from the soil. Seeding blights are caused by many of the same fungi that cause seed decay. Seedling blight symptoms include discolored seedling coleoptiles and roots. Seedlings may have a wet, rotted appearance before they reach the soil surface. Above ground symptoms of blight may include seedlings that turn yellow, wilt and die.

We often forget about potential problems with slugs. In wet cool springs slugs can cause significant damage to corn and soybeans. Slugs thrive in wet cool weather that can cause damage to early season corn with stand reductions. Slugs over-winter as eggs. They like a cool wet habitat and habitats with crop residue. Conservation and no-tillage systems can be at particular risk from slug damage.  Slugs attack seedling and the lower leaves of the young corn plants. They feed on the leaf leaving irregular holes and slime trails.

Seed corn maggot can be a problem in cool wet springs. If the seed sits in the ground and germination is slow the maggot can infect the seed. Small flies (much like a house fly) will lay eggs in fields that have received manure or have crop debris for the year.  The eggs will hatch and the tiny maggot will find the seed and bore in. The maggot will eat the inside of the corn seed. These maggots are tapered, legless, appear headless, pale yellow-white and reach about a 1/4 inch long.

Growing Degree Day Accumulations: Alfalfa Weevil and Black Cutworm Prediction Models

Ken Wise, NYS IPM

Calculating alfalfa weevil activity. You can predict when those eggs will hatch and larval feeding damage would begin using information from an alfalfa weevil growing degree day model.

To make the calculation you’ll need access to maximum and minimum temperature data from March 1 through the current day. Take the high and low temperature of each day and divide it by 2 and subtract 48 degrees F. This will give you the number of heat units for an individual day. If it is a negative number then there were no heat units that day for alfalfa weevil to develop.

(High Temperature + Low Temperature / 2) – 48 F = AW heat units.

Keep a running tally of the accumulated heat units from day to day. Compare the total GDD’s and compare this number against the expected alfalfa weevil growth stage from the following table.

Growing degree Days for peak (50%) Occurrence of Alfalfa Weevil growth stage:

Stage Degree Days(Base 48 F)
Egg 280
Instar 1 351
Instar 2 395
Instar3 470
Instar 4 550
Cocooning 600
Pupa 725
Adult Emergence 815

 (Note: for alfalfa weevil predictions use Base Temp of 48F)

 Black Cutworm Growing Degree Days           

As we stated last week our start date for calculating black cutworm development is April 12 (Penn State). Since then black cutworm moths have been detected in NY. Since it has been detected in the Northeast we can predict its life cycle and when it might be ready to start feeding as larvae. You can predict what stage of development black cutworm is in locally if you happen to know (trap) when the moths arrive with growing degree days with a base temperature of 500F degrees. For example, if we use the BCW trap catch information from Pennsylvania as a place to begin we could use April 12 as a starting point to begin tracking degree days and estimate when to expect signs of  “leaf feeding and cutting”.

 Black Cutworm Degree Days

Degree days Stage Feeding Activity
0 Moth Capture Egg Laying
90 Eggs Hatch
91-311 1st to 3rd instar Leaf Feeding
312-364 4th instar Cutting begins
465-430 5th instar Cutting begins
431-640 6th instar Cutting slows
641-989 Pupa No feeding

(Note: for black cutworm predictions use Base Temp of 50F from April 12 on)

2014 University of Minnesota Black Cutworm Trapping Network

2014 Degree Day Models for Field Crops across New York

Station Location

Alfalfa Weevil

(Base 48) March 1

GDDs (Base 50 F)

March 1

Black Cutworm April 12



































 261  259
Wayland  387  319  315

Source: NEWA Growing Degree Days

Clipboard Checklist

Keith Waldron, NYS IPM


*Walk fields to check general field condition, weed issues, areas of soil erosion

*Watch for early season weeds: winter annuals, chickweed, henbit, field penny cress, shepherd’s purse, giant and common ragweed, purple deadnettle, lambsquarters, redroot pigweed, velvet leaf, Pennsylvania smartweed, common sunflower, quackgrass, foxtail

*Evaluate established legume stands for approximate days til harvest
*Monitor for alfalfa weevil before and immediately after 1st harvest, potato leafhopper
*Monitor new seedings for Pythium blight and Phytopthora Rot Rot.

Small Grains:
*Monitor winter grain fields for growth stage, disease issues, cereal leaf beetle
*Check stands for soilborne virus diseases, Wheat spindle streak mosaic and Soilborne wheat mosaic and powdery mildew symptoms, cereal leaf beetle, weed escapes, goose damage

*Monitor wheat for potential risk of fungal disease issues – consult Fusarium Head Blight prediction model

Pre-plant weed evaluation, timing cultivation and/or pre-plant weed management
Conduct plant population assessments, early season corn pests including seed corn maggot, white grub, wireworm, black cutworm, armyworm, slugs, diseases, weed issues, vertebrate damage

*Prepare land and plant soybeans as soon as conditions allow
*Pre-plant and/or post emergence weed evaluation, timely cultivation and/or weed management
*Conduct plant population assessments, early season corn pests including seed corn maggot, slugs, diseases, weed issues, vertebrate damage

Check and mend fences as needed.
*Check crop growth
*Invasive species, plants harmful to livestock
*Review/Plan rotation system

*Remove / clean soil and crop debris from equipment
Arrange for custom weed control or check your own application or cultivator equipment for repairs.
*Carry appropriate / necessary NYS DEC and EPA required documents: (pesticide applicators license, pesticide labels, MSDS sheets, etc.) with application equipment

  • planting equipment – maintain records on planting rate per field
  • manure spreaders – maintain records on amount spread per field
  • pesticide application equipment – Check nozzles, pumps, etc., recalibrate pesticide application equipment before use. Maintain pesticide use records

* Check stored grain bins for temperature, moisture and signs of mold and insects. Aerate, core, transfer grain or treat as necessary
Check forage allocation and anticipate feed program adjustments as forages from previous year are used up
*Plan where forages should be stored for optimum allocation next feeding season
*Mow around storage bins and facility to minimize pest hiding places