CMEG Crop Management Extension Group

Field Crop News

Website Address: http://fcn.agronomy.psu.edu/

June 26, 2007    Vol. 07:17

IN THIS ISSUE:

Poisonous Pasture Plants and Livestock — Dwight Lingenfelter and Bill Curran, PSU Weed Science

Well it’s almost July and that means the potential for reduced pasture growth and a greater potential for overgrazing. Despite the fact that we have had moist conditions for good pasture growth thus far, we have already received some calls concerning potential livestock poisoning by weeds. Livestock may be forced to graze on weeds that normally they would not, or they may eat weeds out of curiosity. Scout your pastures and remove these weeds before they cause livestock health problems. Keep in mind there are numerous poisonous plants that could invade an area or pasture. Many plants contain potentially poisonous substances that may be toxic to livestock if consumed. In addition, certain plants may be problematic because of mechanical irritation when eaten, photosensitization, and disagreeable tastes or odors in meat, milk or milk products. If you suspect livestock poisoning, call your local extension educator or veterinarian immediately. If death occurs, the stomach contents should be examined for consumed herbage. Identify the suspected plants and remove livestock from the grazing area until all poisonous plants have been removed or destroyed. Table 1 lists only some common weeds and their poisonous properties; many other plants can be toxic to livestock.

Table 1. Selected poisonous plants of the Northeast (Information adapted from Fishel 2000; Hardin 1973; and Hill and Folland 1986 and D. Wolfgang, PSU)
Common name Problem/symptoms Toxic ingredient - toxicity dosage
Bouncing bet Leaves and stem - delayed for several days; depression, vomiting, abdominal pain, diarrhea Saponin - amount equivalent to 3% (dry wt.) of sheep wt. killed within 4 hr.
Buttercups Leaves and stem especially in flower. Dried hay loses toxicity - anorexia, salivation, weakness, convulsions, breathing difficulty, death Protoanemonin - toxicity reported to vary with species, age, and habitat. Generally 1-3% of body weight necessary.
Cherry, black Leaves (wilted leaves are worse), stems, bark and fruit - anxiety, staggering, breathing difficulty, dilated pupils, bloat, death Cyanogenic glycosides - Less than 0.25 lb leaves (fresh wt.) can be toxic to 100 lb animal. Leaves from several small to mid sized branches are sufficient to kill an adult animal.
Clover species Vegetation - Hairballs; Sweet clover: nose bleeding, anemia, abdominal swelling Coumarin with sweet clover - varies
Fern, bracken Entire plant - Dullness, fever, bleeding, loss of appetite, and salivation Glycoside thiaminase - Cattle fed 50% bracken for 30 to 80 days was toxic. Others report that only 20% of diet for 30-60 days was toxic.
Garlic, wild All plant parts - tainted milk and meat. Only toxic in large quantities
Hemlock, poison All plant parts - nervousness, salivation, vomiting, diarrhea, weakness, paralysis, trembling, dilation of pupils convulsions, and coma, death Coniine and others (pyridine alkaloids) - 0.5 to 4% (fresh wt.) equivalent of cattle wt. is toxic. In horses, 0.25% of body weight.
Jimsonweed Entire plant (seeds are most toxic - Thirst, mood swings, convulsions, coma, death Solanaceous alkaloids - 0.06 to 0.09% (dry wt.) equivalent of animal body wt. is toxic.
Locust, black Leaves (especially wilted), seeds, and inner bark - Causes weakness, depression, anorexia, vomiting and diarrhea Phytotoxin robin, glycoside robitinm - bark extract and powder in amount equivalent to 0.04 - 0.1% of animal wt. toxic to horses. Cattle 10-times more tolerant.
Milkweeds Entire plant - depression, muscle tremors, spasms, bloat, difficult breathing. Glycosides and galitoxin - 0.3 to 0.6% of body weight.
Mustards All parts (especially seeds) - oral and gastrointestinal irritation, shaking, salivation, abdominal pain, vomiting, and diarrhea. Thiocyanates, irritant oils, and nitrates (large quantities generally necessary for toxicity)
Nightshade species Vegetation, unripe fruit - loss of appetite, salivation, weakness, trembling, paralysis Solanine - toxic at 42 mg/kg (LD50). 0.1 to 0.3% of body weight.
Pigweed species Foliage (worse in drought) - kidney disease, weakness, edema, rapid respiration Nitrates nitrate oxalates, unknown - 0.5 to 1% of diet. Sheep, hogs, and young calves most susceptible.
Pokeweed, common Entire plant, especially roots - gastrointestinal cramps, weakened pulse, respiration, salivation Phytolacctinm - 10 or more berries can result in toxicity to humans. Unknown for livestock, but perhaps 100-200 berries/1000 lb.
Snakeroot, white Leaves and stem - constipation, loss of appetite, salivation, rapid respiration. Toxin passes through milk (milksickness). Trophine alkaloid - varies from 1 to 2% of animal body wt. after 2 weeks. Toxin cumulative.
St. Johnswort Flowers and leaves - photosensitivity which leads to redness of muzzle, around eyes, and around white hair. Hypercin - uncertain

Key points about weed forage quality and poisonous plants:
• Some weeds have excellent nutritive quality.
• Weeds in the vegetative stage of development usually are more nutritious than more mature weeds.
• Regardless of weed quality, livestock may avoid grazing certain plants because of taste, smell, or toxicity.
• Some plants contain potentially poisonous substances that may be toxic to livestock if consumed — properly identify potential problem weeds and consult with a veterinarian if necessary.
• A productive pasture is important to reduce the potential incidence of toxic weed exposure to livestock. Remember to soil test and maintain the proper lime and fertility levels. If possible, routinely mow or spray to manage weed problems within and around pasture area.

For additional information and resources on plants that are poisonous to livestock see the University of Pennsylvania website at http://cal.vet.upenn.edu/poison/index.html, the Cornell site at http://www.ansci.cornell.edu/plants/index.html, and Purdue's site at http://www.vet.purdue.edu/depts/addl/toxic/cover1.htm. In addition, there are numerous other websites that contain information on this subject. Simply conduct a web search for poisonous plants and livestock.

For information on control of pasture weeds, please consult our PSU Agronomy Guide or visit it online at http://agguide.agronomy.psu.edu/pm/sec6/sec6toc.cfm or http://agguide.agronomy.psu.edu/pm/pdf/table2-6-7.pdf

Soybean Aphids and Spider Mites — Kevin Fry, Armstrong County

Soybean Aphids have been found in Pa soybean fields already this year. Continue scouting, populations can increase very quickly, don’t be caught off guard.

The Soybean Aphid is a small (1/16th in.) greenish—yellow aphid. It has a plump oval—like body with two black cornicles at the top rear of its abdomen viewable with a hand lens. Follow this link for excellent photos of soybean aphids and their look—alikes. http://extension.entm.purdue.edu/pestcrop/2007/issue13/index.html

Soybean aphids feed on the sap of soybean plants causing water stress. Injury appears as stunted plants with yellow leaves. These leaves can have a distorted shape (cupping) similar to Banvel injury. High soybean aphid populations that occur during early soybean growth stages (early flowering R1 — early pod development R3) can cause reduced pod and seed counts. Yield reductions of 20% or more can results from high infestations, particularly in dry years.

The current threshold for treatment is an AVERAGE of 250 aphids per plant with RISING population numbers. The soybean aphid population is very dynamic and can rise and fall drastically within a weeks time. So it is crucial to scout fields weekly to see how the population is changing. While scouting fields, also take note of the number of ladybird beetles observed. One asian ladybird beetle per plant can eat 160 aphids per day.

If treatment becomes warranted, there are a number of insecticides that can be used. Orthene just received a supplemental label for soybean aphids. There are also a number of older insecticides registered for soybeans that show good activity, including Lorsban 4E, Furadan 4F, Dimethoate, AsanaXL, Baythroid, and Warrior.

Spider Mites
The hot dry weather we’ve been experiencing could bring early outbreaks of Spider Mites in Soybeans. High temperatures reduce the time required for a mite to complete its life cycle from egg to adult. Dry conditions suppress the natural diseases of the mite population which slow population growth during periods with adequate moisture.

Early symptoms of spider mite injury appear as leaves with a yellow stippled look along the field margins. As the populations continue to build and injury increases, the yellowing spreads across the field and the area of yellow leaves expands and may turn red.

There are no thresholds available for mites on soybeans. Treatment is recommended when mites become numerous in the field and begin to cause discoloration of the plants, especially the lower leaves. Growers should take into account future weather predictions, because we do know that continued hot and dry weather will aggravate the mite problem, where as cool and wet weather will tend to lesson it. However, if cooler and wetter conditions arrive, we would still suggest keeping a close eye on this pest.

In large fields when damage is seen only along the field margins, a spray directed to the injured area and into the field about 100 feet may contain the problem. Lorsban 4E and Dimethoate are labeled for spider mite control. These controls do not provide long term protection from the pest. Since the spider mites can recover rapidly after treatment, fields need to be monitored closely for population resurgence.

Soybean Rust Update — Kevin Fry, Armstrong County

Scouting for Soybean Rust is in full swing in Pennsylvania. However, as the season progresses with dry conditions and low levels of inoculum and infections in the south, the chances for rust to affect Pa growers in 2007 is rapidly decreasing. We are all familiar with the old saying of hoping that the corn is knee high by the fourth of July. Anne Dorrance, Ohio State University, says that for rust to be an issue for out soybean crop there will have to be a lot of reports of soybean rust present in Kentucky, Southern Indiana by the fourth of July.

United States Soybean Rust Commentary (updated: 06/22/07)
Soybean rust was reported in three new locations June 21, 2007. One was in Cameron County, Texas in a commercial field. The other two were in Louisiana in soybean sentinel plots located in Avoyelles and Rapides Parishes. These parishes are in the central portion of the state approximately 80 miles north of the positive kudzu sites in the coastal parishes of Iberia and St. Mary. On June 14th, a commercial soybean field in Hidalgo County, Texas was confirmed to have soybean rust. This county had rust earlier in the year. Scouting for soybean rust has intensified and soybean sentinel plots are now being monitored throughout all soybean growing areas. Moisture conditions vary, but rains have been somewhat regular in areas with rust and rains have occurred or are expected in most other soybean producing areas in the next few days. The reports of rust occurrences to date are similar to last year with some exceptions of earlier reports of rust in Louisiana and in Texas on a commercial soybean field. Soybean rust has been detected in 10 counties in Florida, five counties in each of Georgia and Alabama, and four Parishes in Louisiana and three counties Texas.

More herbicides registered for sweet corn — Dave Johnson, PSU SEREC and Dwight Lingenfelter, PSU Weed Science

Dow AgroSciences has received registration in sweet corn for several brands of herbicides containing acetochlor. The products FulTime, Keystone, Keystone LA, Surpass, and TopNotch can now be used for preemergence weed control in sweet corn. These new labels will give sweet corn growers more options for annual grass and broadleaf control. (Please note that other herbicides containing acetochlor, including Harness, Harness Xtra, Degree, Degree Xtra, Volley, and Volley ATZ are NOT registered for sweet corn.)

Surpass and TopNotch contain the single active ingredient, acetochlor, while FulTime, Keystone, and Keystone LA also contain atrazine. All of these products are classified as restricted use, so you will need your pesticide license to purchase and use them.

The active ingredient acetochlor is in the same chemical family as the active ingredients in Dual, Lasso, and Outlook, and will control annual grasses small—seeded broadleaf weeds such as pigweeds and eastern black nightshade, plus provide some control of lambsquarters, including triazine—resistant (TR), biotypes. Grasses controlled include foxtails, crabgrass, and barnyardgrass. The formulations that contain atrazine (Keystone, Keystone LA, and FulTime) will add cocklebur, morningglory, ragweed, smartweed, and velvetleaf to the weeds controlled. These products also give some yellow nutsedge control, but should be incorporated for best activity on this weed.

The new labels state that these products can only be used early preplant (up to 30 days prior to sweet corn planting), preplant incorporated, or preemergence. They can NOT be used early postemergence in sweet corn. As is true with most herbicides, activation (rainfall or irrigation) is necessary for best results when used preemergence.

As with all residual herbicides, growers must be careful of rotational crop planting restrictions. For all of these products, corn can be planted at any time after application, but only sorghum, soybeans, and tobacco can be planted the following year. Wheat can be planted 15 months after application. For all other crops, growers must wait until the second year after application for planting.

Market Report — John Berry, Lehigh County Educator

Wheat markets have staged a dramatic and significant price rally since 1 April. Chicago July wheat’s low on April 2nd was $4.26. The high on June 22nd was $6.15. The drive higher really started with the Easter weekend freeze across much of the U.S. winter wheat region—both hard red winter and soft red winter. At the same time, it stopped raining across much of Europe, especially eastern Europe and Russia and the Ukraine. It is also still very dry across West Australia and Canada's wheat crop will not be as big as expected a few months ago because of smaller planted acreage. Overall yields, test weight and quality will be far below expectations. Protein content will generally be low. There have been reports of test weight below 50lb/bushel. That is even useless as feed because there is not much nutritional value. Harvested acres will be much smaller than recent forecasts. The areas with the worst yields and quality are already having field released for destruction by crop insurance adjusters. Remember the crop revenue insurance guarantees are high this year. That means that payments per acre from insurance even at the low end of insured levels will mean a payment of $75 to $100 per acre AND a producer will have no harvest costs. There will be many repercussions from this smaller than expected U.S. HRW crop:

If high energy prices were not enough, Brazil’s farmers are being hit hard by rising fertilizer prices. The price of super triple phosphate fertilizer in April 2007 was 92 percent higher than a year earlier. Potash prices at Brazilian ports have risen by 27 percent over the last year. Higher fertilizer prices have a disproportionate impact on Brazilian farmers because the soils of Brazil are heavily leached of nutrients and require large amounts of fertilizer each year. Because of the higher fertilizer, energy and transportation prices and a strengthening Brazilian currency, it appears that it may take soybean prices of $8 /bushel before Brazilian farmers increase their soybean planted area next year. That may become the season price if the U.S. soy crop declines below expectations or if there is clear evidence Argentina’s farmers are going to cut soybean plantings in favor of corn.

Last Week’s Price Report

Western Pennsylvania
Grain Range Avg
Corn No. 2 3.65-3.85*3.38 3.70
Wheat No. 2 4.82-5.12 4.96
Barley No. 3 2.25 2.25
Oats No. 2 2.00-2.25 2.18
Soybeans No. 2 7.27-7.50 7.39
Ear Corn 97.00-110.00 104.00
Central Pennsylvania
Grain Range Avg
Corn No. 2 4.25-4.40*4.03 4.29
Wheat No. 2 5.10 5.10
Barley No. 3 2.70-2.80 2.78
Oats No. 2 2.20-2.45 2.32
Soybeans No. 2 7.51-7.85 7.71
Ear Corn 119.00-125.00 112.10
Eastern Pennsylvania
Grain Range Avg
Corn No. 2 4.05-4.38 4.37
Wheat No. 2 4.00-5.48*5.80 5.29
Barley No. 3 2.70 2.70
Oats No. 2 1.80-2.00 1.90
Soybeans No. 2 7.25-7.65 7.45
Ear Corn 115.00-128.00 122.66

Got Hay? Need Hay? Try AgMap — Mena Hautau, Berks County Educator

With dry weather pocketing the state, growers may need to go out of their local market to purchase hay. There may be opportunities to market hay. AgMap is the on—line tool for Pennsylvania sellers and any buyer of farm products.

To access AgMap, go to: http://agmap.psu.edu/

The link for hay is on the left hand side of the webpage, under “Featured Search”. You can search by commodity and county or within a certain geographic mile radius.

If you have hay to sell, go to the FAQ link and get information on starting an account.

Upcoming Events

Combined Agronomy Industry / Manure, Crops, Pests & No—till Field Day
Penn State Landisville Research Farm
Friday July 6th, 9:00 AM–3:30 PM
Topics will include: Weed Management in No—till; Composting: Mortality and Nutrient Recycling; Nutrient Balance Sheet and Act 38; Farm Bill and Bio—Fuels Updates;
Herbicide Trials and Chemical Industry Updates; and Cover Crop Management. Featured equipment: No—till equipment of all types: Planters, Drills, Residue Managers.
Manure handling and spreading equipment with demonstrations (water only.)
Registrations: Lancaster Extension, 717–394–6851 $3.00 in advance, $5.00 at the door
Questions? Jeff Graybill 717–394–6851. Landisville Research Farm, Dr. Dave Johnson 653-4728

Agronomic Weed Management Research Tour at Penn State
July 10, 2007
Tuesday, 9:00–12:00 noon
Penn State Rock Springs Agronomy Farm, Centre Co.
Cost: $15
Lunch and handouts will be provided.

A number of experiments will be showcased and available for viewing including many of the new corn and soybean herbicide programs plus the latest information on herbicide resistance, cover cropping and weed management research. Certified Crop Advisor CEU’s will be available at this event.

You must pre register with Lisa Crytser at Penn State to ensure you have a spot at lunch and on the wagons. Please pre—register by July 3, 2007 by phone (814-865-2543) or email (lac8@psu.edu).

2007 Penn State Agronomic Field Diagnostic Clinic — July 24 and 25
July 24 and 25
Penn State Rock Springs Agronomy Farm, Centre Co.

The dates and topics for our annual Diagnostic Clinic have been set. As in the past, the Clinic is a one—day event conducted at the Penn State Agronomy Research Farm near Rock Springs, PA. This year’s Clinic will be held on Tuesday, July 24 and then repeated on Wednesday, July 25, 2007. The topics include cover crop selection and management, no—till planter adjustments and attachments for use in cover crops, an overview of biomass crops for alternative energy use, nitrogen management issues, and pest management topics. As always, various credits will be offered.

Registration forms will be mailed and posted on our CMEG website (http://cmeg.psu.edu/) as time gets closer, so you can register and get additional information on each of the topics.

For additional information or comments about the Diagnostic Clinic contact Dwight Lingenfelter at (814) 865-2242 or by email, DwightL@psu.edu.

Ag Progress Days — August 14–16

Contributors: Dept. Crop & Soil Science: Dwight Lingenfelter, Doug Beegle, and Greg Roth. Extension Educators: Andrew Frankenfield (Montgomery), Don Fretts (Fayette), Kevin Fry (Armstrong), Mena Hautau (Berks), and Mark Madden (Sullivan).

Editor: Kevin Fry

Upcoming Events

Real time pest and heat unit activity: http://psu.zedxinc.com/cgi-bin/site.cgi?location=2&user=psu#

Calendar of Events: http://www.events.psu.edu/cgi-bin/cal/webevent.cgi?cmd=opencal&cal=cal209&

Readers can subscribe electronically to this newsletter at the Field Crop News Web site.

If you have problems subscribing or wish to cancel your subscription, please contact Lisa Crytser by e-mail at lac8@psu.edu or by phone at 814-865-2543.

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