Weekly Field Crops Pest Report 2008
View from the Field
Mike Stanyard (NWNY Dairy, Livestock, & Field Crops Team) reports major white mold infestations in two fields in western NY. He also states that many growers are asking about Hessian fly free dates as they gear up to plant winter wheat. For more information on Hessian fly free dates view the Cornell Guide For Integrated Crop Management.
Most extension educators report corn silage harvest is in process on many farms across the state. Dr. Gary Bergstrom reports observing gray leaf spot disease in a corn after corn no-till field in the Chemung River Valley near Elmira.
Ken Wise (NYS IPM) reports a complex of corn diseases at the Cornell Farm at Valatie. Some of the diseases that have been visually identified are purple sheath spot, gray leaf spot, and northern leaf spot race 3. Ken has collected many of these leaves and is sending them to Dr. Gary Bergstrom for diagnosis.
Weather Outlook 9.11.08
Last week saw warmer than normal temperatures across NY. Most of the state saw temperatures that were 4-5 degrees above normal. In the extreme west, the departures were closer to 2 degrees above normal. Between 100 and 125 Base 50 GDD accumulated across the state, with the southern Hudson Valley and Long Island increasing their GDD accumulation by about 160. Season GDD accumulations across the state range from 1700 in the North Country to 2200 in much of the central part of the state to 2700 in the lower Hudson Valley and Long Island. Most places continue to run about 100 GDD behind last years accumulation, but about 100 GDD ahead of normal.
Precipitation amounts varied greatly from west to east thanks to tropical storm Hanna. Across the Finger Lakes less than 0.5 inches was observed, while 3 inch totals were seen in the lower Hudson Valley and Long Island. Western NY saw up to an inch of rain.
High pressure will move east of NY today allowing moisture to move north into the region by Friday. The weekend at this point looks to be wet, however the different models show varying degrees of moisture. I am leaning toward the more pessimistic outlook in which moisture from hurricane Ike gets pulled northward and gives much of the state a widespread 1 inch rainfall. Up to 2 inches is possible in the west and Finger Lakes. The forecast through early next week keeps showery unsettled conditions over the state. It won’t be a total washout, but showers should be prevalent. Maximum temperature will cool from the 70s early in the period to the mid 60s to low 70s by Wednesday. Wednesday’s temperatures are about normal for mid-Sept. Cloudy conditions will keep nighttime temperatures above normal especially over the weekend. Sunday’s lows will be in the 60s, by Wednesday these readings will drop to the mid 40 to low 50s which is near the normal. Beyond Wednesday a trough will establish over the Northeast keeping temperatures slightly cooler than normal and giving the state normal rainfall.
Soybean Rust Update
Soybean rust has not been detected in New York. The current risk of soybean rust in New York is considered to be low. No management practices are warranted for the remainder of 2008.
Sentinel soybean plots in New York State continue to be scouted weekly in the following counties: Chautauqua, Chemung, Columbia, Cortland, Jefferson, Lewis, Niagara, Oneida, Ontario, Steuben, Wayne and Yates. Plant growth stages in sentinel plots range from R5 to R6. Moderate to high levels of Septoria brown spot and downy mildew are occurring in several of the sentinel plots. Frogeye leaf spot is present at low levels in several locations, and bacterial pustule was detected in Jefferson County. Sentinel plot scouting has been completed for the season in Cayuga, Madison, Schoharie, and Seneca Counties.
Since January of 2008, soybean rust has been reported in eight counties in Alabama; five counties in Arkansas; 10 counties in Georgia, 22 counties in Florida; four counties in Louisiana; 13 counties in Mississippi, and five counties in Texas. Movement of rust spores with the recent hurricane disturbances has moved spores northward. Even if viable spores land in New York soybean fields this fall, the crop is nearing maturity and rust will not impact yield. (Updated September 15, 2008)
NY State Soybean Rust Hotline: 607-255-7850
Soybean Aphid Update
Soybean aphid (SBA) populations remain low again this week across NY, although some increases in populations were observed in a sentinel plot in eastern NY. Reports indicate monitored fields are typically averaging 0 to less than 5 SBA's per plant at this time. The eastern NY sentinel field had an average of 34 SBA's per plant with up to 80 SBA's per plant observed in R6 stage soybeans. All fields reporting were still well below threshold. Natural enemy populations, such as ladybird beetles, are present in most areas.
Crop Growth Stage – Soybeans are generally in mid to later reproductive stages. Some fields in the central southern tier are approaching full maturity. Soybean heights vary from 16 inches to 30 plus inches tall.
Soybean aphid scouting and management – Low soybean aphid numbers typically observed pose negligible risk to soybean yields. Close inspection of fields is still the most reliable source of individualized field information on which to base potential insecticide use decisions. Risk of SBA damage to yields decreases as plants mature. No SBA threshold is available for R6 stage soybeans. Research has shown no economic return on insecticidal applications during the R7 and R8 growth stages.
The national USBRUSA.net website last week reported soybean aphid populations were a concern in Wisconsin, Minnesota, North Dakota, South Dakota, N. E. Nebraska, northern Iowa and Illinois. In those states soybean aphid populations have warranted two insecticide treatments in some areas. By contrast, soybean aphid numbers remain low in New York, Ohio, Indiana, much of Michigan and the southern half of Illinois.
It is possible that the predicted movement of hurricane Ike may carry SBA’s eastward from infested areas of the Midwest. Growers are encouraged to monitor soybean fields for presence of soybean aphids, other insects, and diseases.
Soybean aphid management decisions should be based on a field visit and SBA population assessment. The national soybean aphid management recommendations, including the recommended soybean aphid action threshold for R1 (beginning bloom) through R8 (full maturity) reproductive stage soybeans are:
R1 to R5 growth stages - During the period when the soybean crop is reproductive (i.e. flowering) in the R1 to R5 growth stages, an insecticide application may be necessary when 250 or more aphids occur per plant and approximately 80% of the field is infested and populations are increasing. Sequential scouting in the same field is necessary in order to determine if populations are increasing. Comparing SBA counts over a week or more is necessary.
A higher threshold is required for economic return during the R6 growth stage, but no threshold data is available at this time. If treatment options are considered, ensure pre-harvest intervals of the insecticidal product chosen are met prior to application.
R7 growth stage and later (beginning maturity to full maturity) - During the R7 and R8 growth stages, there is no economic return on insecticidal applications.
For more information see: USDA Public PIPE Website: Management Toolbox - Guidelines - USA
* 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 weed escapes, any patches of herbicide resistant weeds?
* Prepare bunkers, silos for incoming silage.
* Mow around storage bins, barn and farm facilities
* Note presence of potentially invasive weed species such as black and pale swallow-wort, common buckthorns, garlic mustard, Japanese honeysuckle, japanese knotweed, multiflora rose, purple loosestrife, and spotted knapweed
Alfalfa & Hay:
* Monitor alfalfa seedings for weeds, for potato leafhopper & diseases.
* Check established alfalfa stands for potato leafhopper, weed encroachment and disease problems.
* Storage areas cleaned and ready to accept next harvest?
Check grain storage bins for temp, moisture, air flow, drying conditions.
* Plant winter wheat after Hessian Fly-free date
* Note crop growth stage and condition
* Check for European corn borer, armyworm, foliar and stalk rot diseases, vertebrate injury (birds / deer), weed escapes, herbicide injury, nutritional deficiencies, etc.
* Check corn for grain fill issues – mold, insects, vertebrate damage
* Monitor weed populations noting presence of "who", "how many" and "where"
* Harvest corn silage at 65 to 68% moisture and high moisture shelled at 25 to 30% grain, and high moisture ground-ear at 30 to 35% moisture.
* Record corn silage yields by field and quality by storage area, take samples for forage analysis
* Take Soil Samples for fertility analysis
* Take Fall Weed Survey following harvest.
* Note crop growth stage and condition
* Evaluate stand for soybean aphid, white mold, foliar diseases, sudden death syndrome (Fusarium solani f. sp. glyines), and brown stem rot (Phialophora gregata f.sp. sojae)
* Harvest when soybeans reach safe storage moisture level of approximately 13%.
* Review combine settings and speeds to minimize seed damage
Dairy Cattle: Livestock Barn Fly Management:
* Monitor animals and facilities for house fly and stable fly populations
* 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
* Use, replenish, replace fly management materials: sticky fly tapes/ribbons, insecticide baits, natural enemies (parasitoids), fly population monitoring (3 x 5) spot cards
Dairy Cattle: Pasture Fly Management:
* Monitor animals for presence of face flies, horn flies and stable flies. Action guidelines: face flies (average 10 per animal face), horn flies (average 50 / dairy, 200 / beef cattle per animal side), stable flies average 10 per animal (all four legs)
* 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
* Pre-clean in and around grain storage bins in anticipation of soybean and grain corn harvests.
* Keep areas around storage bins and silos clean and mowed
* Provide annual maintenance to manure, fertilizer, and pesticide application equipment
* Prepare combines for corn, soybeans
* Sharpen chopper knives. Check shear clearances, protective shields
* Note any repairs to harvesting equipment as they are cleaned and lubricated.
Keith Waldron: NYS Livestock and Field Crops IPM Coordinator
Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock