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Weekly Field Crops Pest Report 2008

July 10, 2008                 Volume 7 Number 13

1. View from the Field

2. Weather Outlook

3. Know Your Corn Rootworm Beetles!

4. Are soybeans at risk from spider mites?

5. Dairy Cattle Pest Management Resources

6. Soybean Rust Update

7. Soybean Aphid Update

8. Clipboard Checklist

9. Up-coming events

10. Contact Information

View from the Field

Ken Wise
NYS IPM

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Potato leafhopper (PLH) populations were OVER threshold in 18 inch alfalfa at the Cornell Research Farm at Valatie. PLH numbers were at 225 PLHs in 3 samples. This infestation level is over 3 times the economic threshold. There were many more nymphs this week as compared to last week. No other reports of PLH populations exceeding threshold from other areas of the state. Now is the time to WATCH alfalfa fields for PLH….

Mike Stanyard (NWNY Dairy, Livestock, & Field Crops Team) reports soybean aphids (SBA) are present in low numbers soybeans typically 5 or less per plant but occasionally reaching as high as 200 on an individual plant. Many soybean fields in western NY while short are beginning to flower. Now is the time to WATCH soybean fields for SBA….He also reports herbicide damage to soybeans and field corn. Armyworm reported in high infestation levels in field corn in Wayne County. Joe Lawrence (Lewis County) reports armyworm in forage at high infestation levels. Patricia Westenbroek reports deer feeding on corn in many fields in Sullivan County.  

Dr. Gary Bergstrom reports few wheat disease issues with some rust observed and one report of a field infected with a case of severe eyespot root rot (also called straw breaker).

Weather Outlook

Drew Montreu
NOAA NE Climate Center, Cornell University

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Weather Outlook - July 10, 2008

Summary:

This last week saw temperatures generally just a couple of degrees above normal, with some areas in the Hudson Valley upwards of 5 degrees above normal. Precipitation was scarce, with most of the state receiving less than ½” of rain. There were a couple pockets of amounts upwards of an inch, with parts of Southeast New York going over 1”. Growing Degree Days averaged 100-150, with less than 100 in parts of Northern New York. For the year, most areas now have 800-1000 Growing Degree Days, with some small areas of 600-800 in the mountains. This is a couple days on either side of last year’s level for everywhere except the west and mountains, which are still up to a week behind last year. Most of the state has had more growing degrees than normal, with some areas as much as a week ahead of normal values.

Forecast:

Another stretch of generally dry, pleasant weather is upcoming for the next week. This will start today and tomorrow with sunshine behind yesterday’s front, with just a slight chance of a thunderstorm tomorrow. Highs tomorrow will be in the low 80’s, while most areas will flirt with 90 on Saturday. Lows will be near 60 Saturday. A cold front comes through Sunday with a chance for some rain with highs in the low 80s and lows in the mid 60s. Monday temperatures will reach into the mid to upper 70s, with lows near 60. There could be some rain in the east as that front works its way out of the area. Tuesday and Wednesday look dry, with highs near 80 Tuesday and into the mid 80’s Wednesday. Precipitation doesn’t look to be very heavy once again this week, with areas in the east standing the best chance at getting over 1” of rain. The 8-14 day outlook calls for near average temperatures and below normal precipitation.

Know Your Corn Rootworm Beetles!

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While it’s a little early to start scouting for corn rootworm it is best to be prepared. Make sure you know your corn rootworm adult beetles before heading out to the fields. Here’s a review of how to identify the adult rootworms:

Western corn rootworm (WCRW) adults are black and yellow beetles that are approximately 1/4 inch long. The female is yellowish with 3 black stripes on its back, while the male is solid black with a pale yellow area at the tip of its abdomen (see photo, and stay tuned for a picture of a male WCRW). Northern corn rootworm is slightly smaller than the western, and it is bright green in color (see photo).

The northern corn rootworm (NCRW) used to be the predominant species in New York State, but since the arrival of the western in the 1980’s, the western has become the dominant species. When scouting, 1 western corn rootworm equals 2 northern corn rootworm adults. During pollination, developing ears can tolerate many rootworms feeding on silks (10+ per ear) without suffering economic losses.

  
WCRW female               NCRW

Watch of next week’s report for an article on how to monitor corn rootworm in field corn.

Are soybeans at risk from spider mites?

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Isolated areas of the state have been experiencing dry weather conditions. Eighty degree F temperatures are predicted for the next week. Hot weather combined with dry - droughty conditions can increase risk of spider mites becoming a problem in soybeans and field corn. We have not heard of this pest being a problem so far this season but if your fields have been showing drought stress, it would be useful to include monitoring for spider mites in your next field visit.

Two-spotted spider mites are tiny, oval, 8-legged, pale-bodied arachnids.  The feeding of spider mites causes a stippling of leaves.  Severe feeding by many mites causes a bronzing of the leaf.  The injury from spider mite feeding can resemble a foliar fungal disease infection.  Another identifying factor of spider mites is the silk-like webbing they produce.  The webbing can be seen on leaflets and petioles in a heavily infested field.  The mites are able to use the silk to transport by wind to un-infested areas of a field.  When scouting, to help to confirm the presence of spider mites, hold a white piece of paper under a plant.  Tap on the plant, and some of the mites should fall to the paper.  They appear as yellow or yellow brown moving specs. 

Spider mites on soybean:

Early symptoms of spider mite injury on the upper leaf surface:

Spider mite populations can increase extremely rapidly - they can develop from egg to adult in 5 days with high temperatures.  Cool, damp weather often leads to steep declines in spider mite populations by encouraging fungal pathogens to take control.

Spider mites are regular residents of weedy areas at field edges.  During dry weather, if these weed hosts become stressed, spider mites may begin to move into the nearby crop. Thus, an infestation usually begins at field edges and radiates into the field.  While a spot-treatment with an insecticide may be helpful to combat the start of a severe infestation, it is critical to scout the whole field.  Low numbers of spider mites can be present before the injury can be seen from a distance.  When chemical control is chosen for spider mite management, it is critical to bear in mind the risks of "flare-ups" from use of pyrethroid insecticides.

Dairy Cattle Pest Management Resources

Keith Waldron
NYS IPM

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Summer is here and warmer temperatures have been favorable for potential increases in fly pests affecting dairy animals and other livestock.

A quick source of factsheets, management recommendations and other resources on Livestock (dairy cattle, poultry, sheep, goats, swine, and horses)  Integrated Pest Management can be found at NYS IPM Livestock and Veterinary Entomology at Cornell.

For those with a specific interest in dairy barn fly management an archive of a 2 hour Web stream broadcast is available for viewing or download.

Soybean Rust Update

Gary Bergstrom
Plant Pathology, Cornell University

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Sentinel plots in New York State have been established in the following counties: Cayuga, Chautauqua, Chemung, Columbia, Cortland, Jefferson, Lewis, Livingston, Madison, Niagara, Oneida, Ontario, Schoharie, Seneca, Steuben and Wayne. Scouting has begun in many of these plots. We will continue to provide disease updates on these plots as the growing season progresses.

Since the beginning of 2008, soybean rust has been reported on kudzu in one county in Alabama; eleven counties in Florida (two of these counties had reports on coral bean and snap bean and one had a report on soybean); three counties in Louisiana; one county in Mississippi, and three counties in Texas. Reported infected kudzu sites in many counties have been destroyed. Rust was also reported in three states (5 municipalities) in Mexico on yam bean and soybean. These too have been destroyed or are no longer active, except for the recent find in Chiapas. Soybean sentinel plots have been established throughout the Gulf Coast region, and in many parts of the lower Midwest. (Updated June 27, 2008 )

NY State Soybean Rust Hotline: 607-255-7850

NYS Soybean Rust Website

USDA Soybean Rust Website

Soybean Aphid Update

Keith Waldron
NYS IPM

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Soybeans are being monitored by participants in NY’s Soybean Rust / Soybean Aphid Sentinel Project are generally in vegetative growth stages.

Some fields in western NY are approaching early bloom stage.

Soybean aphid populations appear to be present but at low numbers (well below the 250 SBA’s per plant threshold) so far this season. Most reports indicate SBA populations are typically 0 - <5 SBA’s per plant with an occasional report of an individual plant approaching 200 per plant.

National SBA management guidelines can be found at the USDA Public PIPE website.

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

* Maintain crop records by field, including variety, planting date, pesticides used, nutrient inputs including manure, yields, etc.

* Watch for winter annual and other early season weeds, any patches of herbicide resistant weeds?

Field Corn:

* Determine plant populations, make notes on growth stage, effectiveness of early season issues and management

* Check for European corn borer, armyworm, cutworm, foliar diseases, vertebrate injury (birds / deer), weed escapes, herbicide injury, nutritional deficiencies, etc.

* Check no-till fields/fields with high residue or weeds for slug damage, cutworm, armyworm

* Monitor for weeds, note presence of "who", "how many" and "where"

* Check herbicide resistant corn fields for herbicide resistant soybean

* Adjust post emergence weed control actions

Small Grains:

* Monitor winter grains for crop stage (grain maturity), insect problems (cereal leaf beetle, armyworm) and foliar / head diseases

* Evaluate crop for timing harvest

Alfalfa & Hay:

* Monitor alfalfa seedings for weeds, insects & diseases.

* Check regrowth of established alfalfa stands potato leafhopper, weed and disease problems.

* Storage areas cleaned and ready to accept next harvest?

Soybeans:

* Evaluate stand for crop growth stage, weed assessment, soybean aphid, spider mites, deer, foliar disease incidence

* Check herbicide resistant soybean fields for herbicide resistant corn

Dairy Cattle: Livestock Barn Fly Management:

* 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 through out barn

* Order fly management materials: fly tapes, insecticide baits, natural enemies (parasitoids)

* Continue release of purchased natural enemies (fly attacking parasitoids)

Dairy Cattle: Pasture Fly Management:

* Monitor animals for presence of face flies, horn flies and stable flies.

* Check feed bunk / water source locations for signs of stable fly breeding (moist undisturbed organic matter – spilled feed, round bales, etc.) , minimize source of moist organic matter i.e. fly breeding areas in barn and in adjacent animal loafing yard

* Check paddocks for forage quality / quantity, rotate as appropriate

* Check paddocks for vegetation poisonous to livestock

* Consider use of fly traps to help reduce deer, horse and stable fly populations

Storage:

* Pre-clean in and around grain bins before adding newly harvested wheat.

* Keep areas around storage bins and silos clean and mowed

Equipment:

* Note any repairs needed for recently used equipment: tractors, tillage implements, planters, etc. as they are cleaned and serviced.

* Service corn and soybean planter as needed. alfalfa harvesting equipment, and tillage implements

* Calibrate manure spreaders - maintain records on amount spread per field

Up-coming events

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Weed Science Field Days
*Wednesday, July 16, 2008
Robert B. Musgrave Research Farm
1:30 pm - 5 pm
Aurora, NY ( Poplar Ridge Road, connects 90 and 34B)

Aurora Field Day
Wednesday, July 23, 2008
Robert B. Musgrave Research Farm
Aurora, NY ( Poplar Ridge Road, Connects 90 and 34B)

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