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Weekly Field Crops Pest Report 2011

May 20, 2011, Volume 10 Number 3

  1. View from the Field
  2. Weather Outlook
  3. Wet Weather Increases Risk of Potential Winter Wheat Diseases
  4. Is this a year for Soybean aphids?
  5. Barn Flies? – Early Season Efforts Will Pay Off!
  6. Growing Degree Days
  7. Clipboard Checklist
  8. Mark Your Calendars
  9. Contact Information

View from the Field

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I was scouting the Cornell Research Farm in Valatie, NY.
Powdery mildew was found in some of the triticale plots. Depending on the variety a fair amount of the disease could be seen in the lower canopy. If the weather continues to be cool and wet the disease will likely continue to progress up the plant. The photos show the disease on the leaves.

powdery mildew on triticale

Powdery Mildew on Triticale

Alfalfa weevil (AW) adults and 1st-2nd instar larvae were also found on alfalfa at the Valatie farm. There was about 10 to 20% tip feeding by AW larvae.

alfalfa weevil tip feeding

Tip Feeding by Alfalfa Weevil on Alfalfa

alfalfa weevil adult

Alfalfa Weevil Adult

One of the reasons we do not have problems with aphids in alfalfa is thanks to a variety of natural enemies. The result of one such encounter is shown below. This pea aphid was parasitized by a parasitic wasp. The parasitoid wasp lays an egg inside the aphid. After the egg hatches the larva feeds on the aphid ultimately killing it, leaving behind only the aphids exoskeleton (Aphid Mummy). Once the parasitoid is fully developed the adult wasp exits out the posterior of the aphid shell. The young adult then begins it's search for more aphids.

aphid mummy

Aphid that had been parasitized (Aphid Mummy)

ALERT!
While NY does not have a network to monitor black cutworm, several states to our south and southwest are reporting a large number of black cutworms moths captured in blacklight traps. This does not mean that black cutworm will be a problem for us but does signal we should be on the lookout. Why should we be concerned with black cutworm here? Adult moths ride storms from the south and mid-west moving north looking for fields to eat! We have received several weather fronts already this spring. These suggests that there is a good chance we will have adult moths in NY. It will be important to get out and scout corn fields in the weeks ahead!

Weather Outlook

May 19, 2011

Jessica Rennells, Northeast Region Climate Center, Cornell University

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It's been another wet and cloudy week with precipitation ranging from 1 to 3 inches for most of the state. Temperatures have been up to 6 degrees above normal for most of the state. The Base 50 growing degree days have ranged from 25 to 75.

Today (5.19.11) we'll have temperatures in the mid 60's to low 70's with precipitation likely and possible thunderstorms from a low pressure system. Overnight temperatures will be in the upper 40's to near 60 with the possibility of showers, most likely in western NY and the Great Lakes region. Friday's highs will range from the mid 60's to mid 70's with scattered showers and the possibility of thunderstorms. Lows will be in the mid 40's to mid 50's with some continued showers possible. Saturday will bring sunshine and temperatures in the low to mid 70's. Some showers are still possible for northern NY. Overnight lows will range throughout the 50's. Sunday highs will range in the 70's. It should be a nice day overall but showers are possible, more likely for western NY. Sunday's lows will be in the low to mid 50's. Monday temperatures will range in the 70's with a chance of showers and thunderstorms. Lows will be in the mid 50's to low 60's. Tuesday's highs will be cooler in the mid 60's to some mid 70's in the lower Hudson Valley. Showers will be likely. Overnight temperatures will be in the low 50's to low 60's. Wednesday's temperatures will be in the mid 60's to low 70's with showers possible. Lows will be in the upper 40's to lower 50's.

The five day precipitation amounts will range from half an inch to 1.25 inches. The 8-14 day outlook is showing normal to above normal temperatures and above normal precipitation. The one month outlook is showing equal chances for above or below normal precipitation. The May/June/July outlook is showing above normal precipitation. Widespread flooding is still occurring in the Champlain Valley and is possible in the lower Hudson Valley.

Wet Weather Increases Risk of Potential Winter Wheat Diseases

Ken Wise
NYS IPM

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The cool wet weather we have had this spring can enhance risk of winter wheat diseases. These conditions can favor several wheat diseases including powdery mildew and stagonospora nodorum blotch, two of the more common foliar diseases found this time of year. Now is the time to get out, check fields and LOOK for the diseases.

Powdery Mildew
The conditions for powdery mildew (PW) are ideal at the moment. The disease likes temperatures at 60° F or above with wet humid days. Look out the window … wet and cool … that seems to be the theme these days. The mildew forms a white to gray, fungal coating on the leaves of the wheat plant. Under the canopy the lower leaves are usually the most severely infected because of the high relative humidity. As the disease progresses small black fruiting bodies (cleistothecia) develop within white infected areas. Powdery mildew is distributed by airborne spores and or being splashed onto plants by rain.

powdery mildew on wheat

Powdery mildew on wheat. Photo taken by Gary Bergstrom

Stagonospora Nodorum Blotch
This disease loves to be splashed! What I mean is that the disease is transmitted to other plants by rain and thunderstorms dislodging the spores up from the soil surface onto the plants. We have certainly had RAIN this spring …. So the conditions are prime for Stagonospora nodorum blotch (SMB). Sometimes seed can be infected with spores at planting. Make sure you always use certified seed. The greatest yield losses occur when the flag leaf and the next two lower leaves become infected by the time the wheat flowers in late May. The leaf lesions begin as very dark brown flecks or spots, sometimes with a yellow halo. These small irregular lesions expand into oval light brown lesions with dark brown centers. If the disease progress to the wheat head the name of the disease changes to "Glume Blotch". On wheat heads the lesions begin as either grayish or brownish spots on the chaff, usually on the upper third of the glume. As lesions enlarge, they become dark brown and the centers turn grayish-white in color as tiny brown or black dots (pycnidia) develop within them.

stagonospora nodorum blotch

Stagonospora nodorum blotch on wheat. Photo taken by Gary Bergstrom

Monitoring – Now is the time
Monitoring is the key to avoiding crop losses from these two diseases. You will need to assess upper three leaves for symptoms and signs for the diseases in early to mid-May, before flag leaf emergence. You will need to assess 20 plants in different areas of the field to get a representative sample of the occurrence of the disease. A representative sample is important because it gives you a better idea of the severity of the disease across the whole field. If assessments are taken in one or two areas you can bias your efforts. Meaning what you sample in the small area might not be what is happening in the rest of the field.

Action Threshold
The action threshold for both diseases is reached if any amount of disease is observed on approximately 50 percent of main tillers.

Management
The following are management options available to control and their effectiveness on the diseases:

 
PW
SNB
Resistant varieties
2
-
Crop Rotation
2
1
Fungicide seed treatments
-
3
Plant certified disease-free seed
-
2
Foliar fungicides if economical
1
2

Control Measures and Their Effectiveness (1=high to 3=slight)

Is this a year for Soybean aphids?

Keith Waldron,
NYS IPM

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Soybean aphid populations in NY were very low in 2010 and it was actually difficult to find them at all, although populations increased somewhat very late in the season.
 
Since they were first discovered here in 2001, New York soybean aphid (SBA) populations have been variable in time and distribution with alternating years of high and low aphid numbers. SBA's have tended to be problematic in odd numbered years (2007 and 2009). Soybean aphid populations were very low or very localized during 2006, 2008 and 2010. Similar population trends have been observed in other Northeastern and Midwestern states. In high SBA years, their numbers have tended to increase in late June through July. This increase in SBA numbers is generally accompanied by a gradual increase in numbers of natural enemies such as ladybugs, syrphid fly and lacewing larvae and fungal pathogens. These predators and parasites can significantly curb soybean aphid populations.
 
It is not completely understood why SBA populations have this on/off year trend but researchers suspect one possibility is in response to naturally occurring control by a number of natural enemies. High populations of SBA's attract increasingly larger populations of predators that reduce the number of aphids that go from soybeans to their overwintering host, buckthorn, in the fall. The lower overwintering population means fewer aphids are available to move to soybean fields the following spring. Our infestations of SBA's in NY are partially from local overwintering sites and an influx of SBA's carried on weather fronts from the Midwest in July.

Predictions for 2011? If the on/off year historical trends prove correct this could be a year to watch for soybean aphid. It is impossible to predict which areas of New York, if any, will experience outbreak conditions.  Our experience, even in high aphid population years, has been soybean aphids tend to be somewhat localized and are typically not an issue in every field. Field monitoring is necessary to determine when soybean aphids are present and if their population is approaching the average of 250 SBA / plant threshold.

Several factors can contribute to the size of soybean populations including: the size of colonizing population from buckthorn in spring, soybean variety (varieties with resistance are now commercially available), soybean plant health (aphid populations are higher on stressed plants), aphid mortality from natural enemies such as predators, such as the multicolored Asian lady beetle and insidious flower bug, that feed on aphids during the summer and eggs on buckthorn in the fall, fungal outbreaks, heavy thunderstorms, and temperature (the optimum temperature for SBA population growth is 75-80°F; SBA population growth slows or may stop when temps are greater than 90°F).
 
At this time, growers should be aware that scouting for aphids will likely be more important this summer.   There is nothing to suggest that any additional measures should be taken at this time.  We will be keeping close watch for soybean aphids this summer and providing updates in this newsletter throughout the season.

Barn Flies? – Early Season Efforts Will Pay Off!

Keith Waldron
NYS IPM

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Barn Flies? Given the right conditions barns and other livestock facilities can offer great habitats to develop house and stable fly populations. 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. The cooler temperatures so far this season have helped slow down fly population development. 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 outside.
 
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.
 
With dry conditions and sound sanitation as the foundation for fly management, additional tactics can be brought to bear.
 
Choice of animal bedding material. 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 especially for calf pens, has been shown to significantly reduce house and stable fly maggot populations, but may not always be economical or practical. The ability of wood-based bedding to reduce fly populations may differ depending on the source of wood used.

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, are 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 the better is recommended. 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.
 
For more information on IPM for barn fly management see: Integrated Management of Flies in and around Dairy and Livestock Barns and IPM Guide to Organic Dairies 2011.

Growing Degree Days

Keith Waldron
NYS IPM

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CURRENT Accumulated Growing degree days (48F Base):

March 1 - May 18, 2011

Location
Base 48 F
Base 50 F
Chazy
134
95
Geneva
208
157
Highland
309
246
Hudson
256
195
Ithaca
200
150
Watertown
144
106
*Indicates missing data
Data from NEWA

Clipboard Checklist

Keith Waldron
NYS IPM

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General 
*Emergency contact information ("911", local hospital, Chem. Spill emergency contact, other?) posted in central posting area
*Walk fields to check tile flow, check and clear drainage outlets. Look for line breaks.
*Observe wet areas and plot on aerial photo of farm for future drainage considerations and crop decisions
*Maintain crop records by field, including variety, planting date, pesticides used, nutrient inputs including manure, etc.
*Watch for early season weeds: winter annuals: chickweed, henbit, purple deadnettle, field penny cress, shepherd's purse; annuals: giant ragweed, lambsquarters, Pennsylvania smartweed, common sunflower

Alfalfa and Grass Hay:
*Monitor alfalfa for alfalfa snout beetle (In Oswego, Jefferson, Cayuga, Wayne, Lewis, St. Lawrence, Clinton, Essex, and Franklin counties)
*Monitor alfalfa for crop condition, alfalfa weevil, foliar, systemic and crown rot diseases.
*Evaluate established legume stands for winter damage (thinning stand, frost heave, Brown Root Rot), determine average alfalfa stand count, adjust crop plans if necessary
* Evaluate new seedings for plant populations and weeds
*Monitor alfalfa seedings for weeds, insects & diseases
*Evaluate grass hays for maturity to time harvest

Small Grains:
*Monitor winter grain fields for crop growth stage, virus and other foliar disease symptoms, weed pressure, insects (cereal leaf beetle), goose damage
*Check winter wheat for signs of foliar diseases, potential need for fungicide application.

Field Corn:
*Finish corn planting as soon as field conditions allow
*Using a Bt hybrid? Have a refuge plan?
*Post emergence: Determine corn plant populations, make notes on germination problems, monitor for weeds, note presence of "who", "how many" and "where"
* Early season corn pests: seedling blights, seed corn maggot, white grub, wireworm, black cutworm
*Adjust post emergence weed control actions

Soybeans:
*Pre-plant field assessment and weed evaluation
*Evaluate stand establlishment

Pastures:
*Check and mend fences as needed.
*Check crop growth
* Check for presence of undesirable or plant species harmful to livestock.
*Review/Plan rotation system

Equipment:
*Arrange for custom weed control or check your own application or cultivator equipment for readiness or need for repairs.
*Check nozzles, pumps, etc., recalibrate pesticide application equipment regularly before use.
*Calibrate planting equipment - maintain records on crop planting rate per field
*Calibrate manure spreaders - maintain records on amount spread per field

Storage:
*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

Dairy Cattle Barn Fly Management:
*Monitor animals and barn area for house fly, stable fly and other pest management needs including presence of rodents and birds.
*Check facilities for favorable fly breeding conditions: (organic matter + moisture): leaks in watering systems, roof gutters for leaks and potential overspill, drainage,
*Sanitation, sanitation, sanitation - clean animal resting areas, feed troughs, minimize source of moist organic matter i.e. fly breeding areas in barn and in adjacent animal loafing yard
* Continue fly monitoring: install "3X5" index card fly speck monitoring cards throughout barn
*Use, replenish, replace fly management materials: sticky fly tapes/ribbons, insecticide baits, natural enemies (parasitoids), fly population monitoring (3 x 5) spot cards
*Consider purchase and release of Muscidifurax raptor and/or M. raptorellus natural enemies of house and stable fly pupae.

Cattle on Pasture:
*Monitor animals for horn fly, face fly and other pest management needs including presence of poisonous plants.

PESTICIDE EMERGENCY NUMBERS

Emergency responder information on pesticide spills and accidents CHEMTREC:  800-424-9300

For pesticide information:

National Pesticide Information Center: 800-858-7378

To Report Oil and Hazardous Material Spills in New York State: NYS Department of Environmental Conservation Spill Response: 800-457-7362 (in NYS); 518-457-7362 (outside NYS)

Poison Control Centers: Poison Control Centers nationwide: 800-222-1222

If you are unable to reach a Poison Control Center or obtain the information your doctor needs, the office of the NYS Pesticide Coordinator at Cornell University, 607-255-1866, may be able to assist you in obtaining such information.

Mark Your Calendars


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CORNELL UNIVERSITY'S SMALL GRAINS MANAGEMENT FIELD DAY, Musgrave Research Farm, 1256 Poplar Ridge Road, Aurora, NY, Thursday June 2, 2011. The Program will run from 10:00am-12:00 noon, registration begins at 9:30.
 
An educational program of the Integrated Field Crop, Soil, and Pest Management Program Work Team in conjunction with Cornell Cooperative Extension will be hosting the Small Grains Management Field Day with research demonstrations and presentations of interest to the local farming community.   DEC and CCA credits will be available.  For more information, please contact Larissa Smith at lls14@cornell.edu or 607-255-2177

Contact Information


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Keith Waldron: NYS Livestock and Field Crops IPM Coordinator
Phone: (315) 787 - 2432
Fax: (315) 787-2360
Email: jkw5@cornell.edu

Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock
Phone: (518) 434-1690
Fax: (518) 426-3316
Email: klw24@cornell.edu