Weekly Field Crops Pest Report 2007
View from the Field
Western NY and Finger Lakes
Julie Dennis, NYS IPM
Potato leafhoppers were present at low levels in 2 Cornell alfalfa variety trials located in Wyoming County. I only observed adult PLH, no nymphs.
Reports of soybean aphids are coming in from around the soybean producing areas of the state. Observations from Cortland, Cayuga, Livingston, Ontario, Seneca, and Wayne Counties indicate that aphids are at low to moderate populations. All soybean scouting eyes should be on the lookout for aphids and, given the dry weather, spider mites. Not sure what to look for?
Spider mites on soybean leaf
Spider mite injury on soybean leaf:
Don’t worry yet, those photos were taken in 2005.
Another soybean pest to be on the lookout for is the bean leaf beetle. We saw bean leaf beetle for the first time in NY late last season. Mike Stanyard has already spotted one in Seneca County this year.
Photo taken by Mike Stanyard
Potato leafhoppers can be found in most fields in Eastern NYS. Over the past week I have found them in Orange, Schoharie, and Columbia Counties. A field at the Cornell Research Farm in Valatie had potato leafhoppers over threshold. In three sets of 10 sweeps each there were an average of 150 potato leafhopper nymphs. The following picture shows potato leafhopper damage (also called “potato leafhopper burn”) to alfalfa field scouted this week.
The PLH damaged field had not been cut yet and is about 25 inches tall. In neighboring cut fields PLH were far below threshold.
Soybean aphid populations have increased in our Columbia County SBR sentinel site. Two weeks ago no soybean aphids were found, while this week there was an average of about 20aphids/plant. They ranged from 0 - 100 aphids/plant.
Both the Multi-colored Asian Lady Beetle (Harmonia axyridis) and the 7-Spotted Lady Beetle (Coccinella septempunctata) ) also were observed in this field.
Fusarium Head Blight (Scab) Update
One of the most devastating diseases of wheat in NY is Fusarium head blight (FHB), 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 a mycotoxin.
Scab is caused by airborne spores of the fungus Fusarium graminearum that dwell in nearby 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 generally not reduced by crop rotation or other cultural practices. Extended periods of warm, moist weather at crop flowering can cause the anthers to be infected just after their emergence, killing the florets and preventing kernels from developing.
Across NY, winter wheat flowered between May 29th and June 10th. Although there were scattered rain showers on June 3, 4, and 5 in the Finger Lakes region, weather conditions were mostly dry across NY wheat areas during flowering. Therefore, the risk of FHB infection at flowering was low. The Penn State FHB Risk Assessment Tool continues to show low risk of disease in NY.
In locations where wet weather was experienced during wheat
flowering, now is the critical time for farmers to be scouting their fields to
determine if wheat is heavily infested. Symptoms of scab become visible on
emerged heads soon 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 or chalky white. Spikes that
are infected later than flowering will produce diseased kernels that are small
and shriveled in appearance. Free
testing of wheat for the vomitoxin is available at The Star of the West Mill in
Churchville, near Rochester. If scab is present in a wheat field, experts
recommend turning up fans on the combine to blow out small, lightweight
kernels, and taking measures to clean the wheat.
There will soon be another tool in the FHB IPM toolbox! A new variety of soft white winter wheat called Jensen has been developed in the Cornell Small Grains Breeding Program, led by Mark Sorrells. Jensen is more resistant to FHB than currently available soft white winter wheat varieties, and should be widely available for fall 2008 plantings.
Wheat Harvest - Preparing Bins to Avoid Pest Problems
You have nurtured the wheat crop since planting, watched
closely for nutritional needs and pests, tuned in the weather channel and kept
tabs on the commodity exchange. Now that wheat heads are beginning to lighten
in color it won't be too long before it's harvest time. Will your storage bins
Most producers are quite familiar with the in-ground aspects of wheat
production. To maintain the profits a good yield can bring, make and follow a
plan to protect the grain while in storage. Grain storage will not improve
grain quality. However, proper management of grain during storage will
protect the quality present at harvest.
Sampling for Potato Leafhopper in Alfalfa
Scouting alfalfa fields is the key to early detection of potato leafhopper infestations. Use a 15-inch diameter sweep net to determine the potential risk a potato leafhopper infestation may pose to your alfalfa. Scouting for potato leafhopper starts after the first cutting of alfalfa (about the first part of June) till the first fall frost. You will want to use a potato leafhopper sequential sampling plan to determine if an infestation requires management or not. The first thing to do is determine the height of your alfalfa. Smaller plants are more vulnerable to potato leafhopper; thus there are different action thresholds for different heights of alfalfa. The second thing you will need to know is how to sample for potato leafhopper. A sample consists of a set of 10 sweeps of the net. A sweep is one pass in front of you as you walk through the alfalfa. The return swing is counted as another sweep. Sequential sampling reduces the time spent in each field and tells you whether to treat (management action) or not treat (no management action). Sequential sampling is particularly helpful in minimizing time required to make a management decision in situations where PLH populations are very high or very low. Use the following chart to determine potato leafhopper infestation levels.
N= No management needed at this
timep"> T= Management needed as soon as
possible Write down the number of potato leafhoppers for each sample taken on the
card. Add each sample to the next, keeping a running total of potato leafhoppers. You will
need to take at least 3 samples using the sequential sampling method. On the
sequential sampling card “N” is defined as no treatment (no management) needed
at this time and “T” is defined as treatment (management) needed within in a
week. If the sample is smaller than the “N” number stop and scout 7 days later.
If the number of leafhoppers is larger than the “T” number then management
action needs to be taken within a week. If the number of potato leafhoppers
fall between “N” and “T” then continue and take the next sample till a decision
can be determined. Check out our online PLH Sampling Guide for a printable
version of the sequential sampling chart.
N= No management needed at this
T= Management needed as soon as possible
Write down the number of potato leafhoppers for each sample taken on the card. Add each sample to the next, keeping a running total of potato leafhoppers. You will need to take at least 3 samples using the sequential sampling method. On the sequential sampling card “N” is defined as no treatment (no management) needed at this time and “T” is defined as treatment (management) needed within in a week. If the sample is smaller than the “N” number stop and scout 7 days later. If the number of leafhoppers is larger than the “T” number then management action needs to be taken within a week. If the number of potato leafhoppers fall between “N” and “T” then continue and take the next sample till a decision can be determined. Check out our online PLH Sampling Guide for a printable version of the sequential sampling chart.
Soybean Rust Update
NYS 2007 Asian Soybean Rust Status
Most of the twenty sentinel plots have been planted in the following New York counties: Cayuga, Chautauqua, Chemung,Chenango, Columbia, Cortland,Jefferson, Montgomery, Oneida,Onondaga, Ontario, Orleans,Oswego, St. Lawrence, Seneca, Steuben, Suffolk, Wayne, and Wyoming. Scouting in these plots should begin in the next week. Updates on scouting efforts in these sentinel plots will be posted weekly on the NY State Soybean Rust Information Center.
Scouting for soybean rust has intensified nationally with most of the sentinel plots being monitored regularly throughout most of the soybean growing states, and north to Canada. On June 14th, a commercial field in Hidalgo County, Texas was confirmed to have soybean rust. Soybean rust was found on volunteer soybeans in this county earlier this year as well as last year on late planted soybeans. This is the second detection of rust on soybean this year in Texas. Soybean rust has also been detected on kudzu in 10 counties in Florida and in five counties in each of Georgia and Alabama, two counties in Louisiana and one in Texas. (Updated June 21, 2007 )
NY Soybean Aphid Update
From: NY section of the United States Soybean Rust Soybean Aphid Commentary.
New York State Agricultural Statistics estimates 210, 000 acres of soybeans were planted in NY this season. Most soybeans are currently in the early stages of emergence between the unifoliate and V3 leaf stage.
Soybean aphids (SBA's) were reported last week (6/11-13/07) by Cornell cooperative extension personnel in south central and central NY. Where present, most fields had 0-3 SBA's per plant. A few central NY fields, however, in Ontario and Wayne Counties had counts averaging 25 per plant with as many as 100 per plant on unifoliate soybean seedlings. Reports this week indicate soybean aphid populations have been also been observed on young soybean seedlings in Cayuga (central and Columbia (eastern) NY. The Columbia county site found an average of 20 SBA’s per plant.
Low numbers of natural enemies such as lady bird beetles (Coccinellid spp) have been observed. http://www.sbrusa.net/
* Initial stand assessment: plant populations, seedling diseases
* Begin monitoring fields for presence of soybean aphids, and other insects, including natural enemies such as lady bird beetles.
* Check droughty fields for presence of spider mites
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
Dairy Livestock Pasture Fly Management:
* Monitor animals for face, horn, and stable fly populations
* Check feed troughs, around waterers for signs of stable fly breeding.
* Consider use of traps if horse and stable fly populations are a problem
Growing Degree Days in NYS
CURRENT Accumulated Growing degree days (48F Base) as of March 1 - June 19, 2007
Growing degree Days for peak (50%) Occurrence of Alfalfa Weevil growth stage:
(Note: for alfalfa weevil predictions use Base Temp of 48F)
SEED GROWERS FIELD DAY
NYSIP Foundation Seed Barn
WEED SCIENCE FIELD DAYS
Valatie Research Farm – July 6
Robert B. Musgrave Research Farm- July 11
H.C. Thompson Research Farm- July 12
AURORA FIELD DAY
ROBERT MUSGRAVE RESEARCH FARM
Julie Dennis: Western NYS IPM Area Educator, Livestock and Field Crops