Weekly Field Crops Pest Report 2009
View from the Field
Alfalfa weevil (AW) infestations have increased across
Wheat leaf rust is disseminated on airborne spores and travels
on storms for the southern part of the
Brain Aldrich (Cayuga County CCE) reports a winter wheat field over economic threshold for cereal leaf beetle. This field was treated with on insecticide.
Weather Outlook May 29, 2009
NOAA Northeast Climate Center, Cornell University
Temperatures last week were slightly above normal, with much
of state seeing temperatures three to six degrees warmer than average.
Areas in the Tug Hill Region and
There were 75 to 100 base 50 growing degree days for most of
the state in the last week. The higher elevations of Southern New
York were slightly less, along with the Adirondacks and
The weather is looking a little more active in the upcoming week. A storm system has been affecting the state for the past two days and will continue to bring a chance for rain today into early Friday. This low will depart tomorrow, with the chances for sun increasing the further west you go. A weak high pressure will build in for Saturday, with highs within a few degrees of 70. Sunday looks cooler, with highs in the upper 50s in the north ranging to the low 70s Downstate. Most areas should end up in the low to mid 60s. Both days could see some scattered showers. Another storm system will bring better chances for rain Monday and Tuesday. Highs Monday will mostly be in the mid to upper 70s, with temperatures Tuesday ranging from the low 60s in the west and north, to near 80 Downstate. Wednesday will likely be dry, with highs mostly within a few degrees of 70. Low temperatures throughout the period should range from the upper 40s to low 50s on average. Rainfall totals over the next 5 days look like they will be highest in the north, where 1.25 to as much 2 is possible. The rest of the state should get from 0.5 to 1.5. The outlook for the next 8 to 14 days is calling for near normal precipitation with below normal temperatures.
Alfalfa Weevil Management: Beneficial Insects Are On Our Side
Alfalfa weevil larvae have been seen in several locations over the past couple of weeks. Biological control agents are a significant reason that alfalfa weevil (AW) often remains well below economic thresholds in NY.
Within 10 years of the arrival of the invasive alfalfa weevil
While searching for alfalfa weevil pupae later this month or in early June, keep your eyes out for the parasitoid pupae, too. Alfalfa weevil pupae can be found inside small net-like, pea-sized cocoons generally found in lower regions of the plant on or 2-3 inches above the soil surface. The alfalfa weevil pupa is surrounded in a white to tan webbing, often associated with a leaf, and a wasp pupa is instead surrounded by a small hard brown capsule-shaped pupal case (see photos). Enclosed in the brown case is the wasp pupa, which has grown up using the alfalfa weevil larva as its food source.
Alfalfa weevil pupae
Pupae (within their cocoons) of parasitic wasps of Alfalfa Weevil
The two most common parasitic wasps of AW in NY are in the genus Bathyplectes. Their pupae are enclosed within the mahogany colored shells, or cocoons, with white bands (2nd and 3rd from the left in the above photograph). These two parasitoid species tend to lay eggs in the early alfalfa weevil larval stages. Only a single parasitoid can successfully develop in a host weevil larva. The two species can be distinguished from each other as pupae. Batheplectes anurus has a raised white band and the cocoon has the unusual habit of jumping when disturbed. B. curculionis does not have a raised white band, and the cocoons do not jump.
Dont forget to review the NY alfalfa weevil scouting guidelines in our Alfalfa Weevil Management Guide.
Will Conditions be Favorable for Fusarium Head Blight (Scab) This Year?
One of the most devastating diseases of wheat is Fusarium head blight, or scab. The disease reduces yield by decreasing the number of viable kernels, but the more significant impact is that the fungus in diseased kernels may produce DON, a mycotoxin called deoxynivalenol (DON). DON is sometimes called vomitoxin because of the impact on the digestive system of swine and other animals with simple stomachs. The rejection of infected grain by buyers is the most significant cause for wheat losses to Fusarium head blight.
Scab is caused by airborne spores of the fungus Fusarium graminearum that dwell in nearby or distant crop debris, including corn stalks and wheat straw. This is the same fungus that can cause root, stalk, and ear rots of corn. Since the fungus is very widespread, likelihood of exposure is not reduced sufficiently by crop rotation or other cultural practices. Extended periods of warm, moist weather at crop flowering can cause the florets to be infected just after anther emergence, killing the florets and preventing kernels from developing. Symptoms of scab become visible on emerged heads within weeks after flowering. During early grain fill, the disease shows up as pink to salmon orange on infected kernels. As kernel fill progresses, the infected kernels appear bleached.
There is a valuable predictive tool available online: the Fusarium head blight Risk Assessment Tool. Gary Bergstrom tells us that this model mainly predicts the likelihood of spore build-up based on temperatures and rainfall amounts prior to wheat flowering. Using the new 24-48 hour forecast weather feature of the model, one can also get an idea of the favorability for actual infection. It shows us a ball-park of areas to focus our scouting efforts. Unfortunately, the model does not accurately predict the level of toxin contamination in grain, particularly if there is a sustained rainy spell during grain-fill.
Please note that the only fungicide available in
Growing Degree Days and Alfalfa Weevil Development in NYS
CURRENT Accumulated Growing degree days (48F Base):
March 1 - May 28, 2009
*Indicates missing data
Data from NEWA
Growing degree Days for Peak (50%) Occurrence of Alfalfa Weevil growth stage:
(Note: for alfalfa weevil predictions use Base Temp of 48F)
Source: R.I. Carruthers
NYS Soybean Rust Information Center Update - 5/26/09
2009 soybean rust detections to date have been on kudzu in
Emergency contact information (911, local hospital, Chem. Spill emergency contact, other?) posted in central posting area
Review EPA Worker Protection Standard training and posting compliance needs
Maintain crop records by field, including variety, planting date, pesticides used, nutrient inputs including manure, etc.
Watch for winter annual and other early season weeds, any patches of herbicide resistant weeds?
Storage areas cleaned and ready to accept upcoming hay harvest?
Determine plant populations, make notes on emergence problems
Gaps in row? Check for seed corn maggot, wireworm, cutworm, armyworm, seedling blights, birds, seed placement issues
Check no-till fields/fields with high residue or weeds for slug damage
Monitor for weeds, note presence of who, how many and where
Adjust post emergence weed control actions
Monitor winter grains for crop stage (flag leaf?, heading?), insect (cereal leaf beetle, armyworm) and disease problems
Check wheat for foliar diseases, fusarium head blight, wheat rust
Evaluate crop for adequate stand and plant vigor
Alfalfa & Hay:
Monitor alfalfa seedings for weeds, insects & diseases.
Check established alfalfa stands for alfalfa weevil, potato leafhopper weed and disease problems.
Storage areas cleaned and ready to accept upcoming harvest?
Evaluate stand emergence seedling blights, seed corn maggot, weed assessment
Evaluate stand for presence of soybean aphid
Dairy Livestock Barn Fly Management:
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
Check waterers, drainage, roof gutters for leaks and potential overspill
Begin fly monitoring: install 3X5 index card fly speck monitoring cards through out barn
Order fly management materials: fly tapes, insecticide baits, natural enemies (parasitoids)
Check storage areas (bunk silos, etc.) for readiness to accept first cutting
Check forage allocation and anticipate feed program adjustments as forages are used up from previous year
Plan where forages should be stored for optimum allocation for feeding
Keep areas around storage bins and silos clean and mowed
Note any repairs needed for recently used equipment: tractors, tillage implements, planters, etc. as they are cleaned and serviced.
Service corn planter as needed. alfalfa harvesting equipment, and tillage implements
Soybean planter and alfalfa harvesting equipment ready?
Calibrate manure spreaders - maintain records on amount spread per field
PESTICIDE EMERGENCY NUMBERS
Mark Your Calendars
June 4, 2009 -- Small Grains Management Field Day, Musgrave Farm, 1256 Poplar Ridge Rd, Aurora, NY
July 7, 2009 -- Cornell Seed Growers Field Day,
July 15, 2009 -- Weed Science Field Day, Thompson Research Farm,
July 15, 2009 -- NYSABA Summer, BBQ, Musgrave Farm,
July 15, 2009 -- Weed Science Field Day, Musgrave Farm,
July 23, 2009 -- Aurora Farm Field Day, Musgrave Farm, 1256 Poplar Ridge Rd, Aurora, NY
Aug. 10-14, 2009 -- Soil Health Training Workshop, Ithaca, NY
Keith Waldron: NYS Livestock and Field
Crops IPM Coordinator