IDENTIFY AND CONTROL POISON HEMLOCK
Rory Lewandowski, Extension Educator Wayne County and Crossroads EERA
As I have driven around the county the past week or so, I have noticed some patches of poison hemlock on roadside banks and also in some fields. Specifically I have seen poison hemlock in some alfalfa fields. This is a concern because all parts of this plant including leaves, stems and roots are poisonous when ingested. This is a good time to scout both hayfields and pastures for this weed and take steps to control it. This is not a weed that livestock owners can afford to ignore.
Poison hemlock has an appearance similar to wild carrot and is a member of the parsley family. The plant has compound leaves made up of multiple leaflets that are finely divided and have a triangular shape. Some descriptions say the leaf has a lacy appearance. One of the key identifying characteristics is the stem. The stem of poison hemlock is smooth, hairless, and hollow and is colored with purple blotches.
The plant is a biennial and can be overlooked in its first year when it produces only vegetative growth. It becomes very noticeable during the second year when, after early vegetative growth it bolts and produces a flower stalk that can be 3 to 8 feet in height. The small white flowers are arranged in an umbrella-like cluster. Up to forty thousand seeds per plant can be produced. As the seeds mature in August and September they are easily spread by moving water, animals, people and mechanical activity such as mowing. This is an invasive plant that can take over open areas and crowd out beneficial plants.
As mentioned at the beginning of this article all parts of poison hemlock are toxic. According to a Purdue University Extension fact sheet; “Lethal doses can be small, so it is important not to let animals graze or feed on poison hemlock. In the case of horses, 4 to 5 pounds of the leaves may be lethal. One to 2 pounds can be lethal for cattle and 4 to 8 oz for sheep. Young animals are more susceptible. Symptoms may appear within 1 hour of ingestion. This starts with a nervous stimulation and can progresses in 2 to 3 hours later into respiratory paralysis. In rare cases the animal may have convulsions. In many cases symptoms include, bloating, incoordination, intestinal irritation, dilation of pupils, rapid and weak pulse, loss of appetite, salivation, and blue coloration about the mouth. Ingestion of poison hemlock in days 55 to 75 of gestation may result in birth defects.”
Control of poison hemlock needs to occur while the plant is in the vegetative state, so early spring is a good time to control second year plants and fall a good time to control first year plants. Herbicides can be effective in killing poison hemlock. Recommended herbicides and herbicide products include 2,4-D, dicamba (Banvel/Clarity), Crossbow (2-4,D plus triclopyr) and glyphosate. The 2012 Ohio and Indiana Weed Control Guide rates Crossbow and glyphosate as a little more effective than 2,4-D or dicamba products. Be aware that all of these herbicides are broadleaf weed killers, which means if these products are applied in a pasture they will kill desirable broadleaf plants such as clover, and in an alfalfa field will kill alfalfa plants. Spot spraying is recommended when infestations are small and limited in scope.
Tuesday, April 17, 2012
Monday, April 9, 2012
Central Ohio Grazing School
The Ohio Forage and Grassland Council will be hosting a
Pasture Management Workshop/ Grazing School/ Pasture for Profit Program at the
farm of the newest Ohio Forage and Grassland Council (OFGC) Director Val
Jorgensen’s Farm, 5851 East Walnut Street, Westerville, Ohio. Map of the location is available at http://www.jorgensen-farms.com/map.htm
. The farm is just west of State Route
605 and north of State Route 161. There
will be three sessions April 24 and 26 from 6:00 p.m. to 9:00 p.m. and Saturday
28 at 9:00 a.m. until noon that will include a pasture walk and a grazing
system design exercise.
The sessions will cover setting your goals and objectives,
evaluating your resources, understanding plant growth, grazing economic, forage
species selection, developing contingency plans for drought, mud and deep snow,
soil pasture fertility, fencing and livestock watering systems.
Producers need to register by April 20, 2012 by contacting
OFGC at bobhendershot2011@gmail or 740-477-1114. Please see the registration form. A registration fee of $50 per farm will
include materials, Pasture for Profit notebook, Pasture Stick, refreshments and
Saturday’s lunch.
Tuesday, April 3, 2012
Successful Alfalfa Establishment
SUCCESSFUL ALFALFA ESTABLISHMENT
Rory Lewandowski, Extension Educator Wayne Co. and Crossroads EERA
April is a good month to plant and establish a new stand of alfalfa. The earlier in the month planting is done, the better. Once an alfalfa plant has germinated, that new plant needs between 6 to 8 weeks to get a good root system established that enables it to handle warmer and drier summer weather. At about 8 to 10 weeks after emergence the alfalfa plant pulls the growing point below the soil surface. This process is called contractile growth. Once contractile growth occurs the alfalfa plant is considered a true perennial. The protected growing point below the soil surface is the reason why the alfalfa plant can survive winter temperatures, close cutting and grazing.
Some of the most common questions regarding successful alfalfa establishment include soil fertility, planting depth and weed control. All three factors need to be addressed to successfully establish an alfalfa stand. The basis for any decisions regarding the application of lime, phosphorus and potassium fertilizer is a soil test. The recommended soil pH for an alfalfa stand is 6.8. Remember that it takes 6 to 9 months after lime is incorporated and mixed into the tillage zone before the target pH is reached. If soil pH is below 6.5, it is probably a wise decision to apply lime this spring and aim for a late summer planting. A soil test can also help determine if phosphorus and/or potassium needs to be applied before planting. Phosphorus is a critical element to aid a new plant in establishing a good rooting system. The point here is that lime and fertilizer can represent a significant dollar investment and guessing as to the need and quantity can be expensive. So, as the saying goes; “Don’t guess, soil test”.
Weed control in an alfalfa stand really needs to begin before the crop is planted. Herbicide options in an established alfalfa stand are limited. Perennial broadleaf weeds and grasses should be managed and controlled in the crops previous to the alfalfa rotation. The general rule of thumb is that at least 95% of the weed control in a forage crop is provided by developing a dense, healthy stand that will not allow weeds to invade.
Just like other agronomic crops, weeds that emerge with the new alfalfa seedlings are the most destructive. The goal should be to maintain the new seeding relatively weed free for the first 60 days. These factors often make it necessary to use an herbicide with a pure seeding of alfalfa. There are a few herbicides that are commonly used when establishing a pure stand of alfalfa. Balan or Eptam can be used as pre-plant incorporated herbicides to provide control of annual grasses and some broadleaf weeds. Butyrac and Bromoxynil can be used to provide early post emergent control of some broadleaf weeds when weeds are no more than 2 inches tall. Clethodim and Sethoxydim or Sethoxydim plus Dash can control annual and perennial grasses in alfalfa. Prowl H2O provides residual control of most annual grasses and certain broadleaf weeds, but must be applied prior to weed emergence and the seedling alfalfa must be in the at least the 2nd trifoliolate stage of growth but not more than 6 inches tall. Imazethapyr and Imazamox control annual broadleaf weeds and suppress or control grass weeds, and must be applied when alfalfa is in the 2nd trifoliolate state or larger and when weeds are 1 to 3 inches tall or when rosettes are no more than 1 to 3 inches wide. More details are available in the 2012 Ohio and Indiana Weed Control Guide. Take the time to read and follow label directions. Herbicide use on forage crops such as alfalfa can involve harvest and grazing restrictions, in addition to specific limitations regarding the timing of the herbicide application.
Incorrect planting depth has been responsible for many poorly established stands of alfalfa or seeding failures. Alfalfa is a small seed and should not be seeded too deep. The recommended seeding depth for alfalfa is one-quarter to one-half inch deep. It is better to err on the side of planting shallow rather than too deep.
Another factor that works hand in hand with planting depth is correct calibration of the planter for seeding rate. The Ohio Agronomy Guide recommends seeding alfalfa at 15 lbs/acre of pure live seed for a pure stand. If a coated alfalfa seed is used, be aware that coatings can account for up to one-third of the weight of the seed. This can affect the number of seeds planted if the planter is set to plant seed on a weight basis. Seed coatings can also dramatically alter the flowability of the seed through the drill, so be sure to calibrate the drill or planter with the seed being planted.
Finally, use fungicide treated seed to provide protection against seedling diseases and make sure the seed is planted with the proper bacterial inoculum that has been maintained under conditions that ensure the inoculant is viable.
Rory Lewandowski, Extension Educator Wayne Co. and Crossroads EERA
April is a good month to plant and establish a new stand of alfalfa. The earlier in the month planting is done, the better. Once an alfalfa plant has germinated, that new plant needs between 6 to 8 weeks to get a good root system established that enables it to handle warmer and drier summer weather. At about 8 to 10 weeks after emergence the alfalfa plant pulls the growing point below the soil surface. This process is called contractile growth. Once contractile growth occurs the alfalfa plant is considered a true perennial. The protected growing point below the soil surface is the reason why the alfalfa plant can survive winter temperatures, close cutting and grazing.
Some of the most common questions regarding successful alfalfa establishment include soil fertility, planting depth and weed control. All three factors need to be addressed to successfully establish an alfalfa stand. The basis for any decisions regarding the application of lime, phosphorus and potassium fertilizer is a soil test. The recommended soil pH for an alfalfa stand is 6.8. Remember that it takes 6 to 9 months after lime is incorporated and mixed into the tillage zone before the target pH is reached. If soil pH is below 6.5, it is probably a wise decision to apply lime this spring and aim for a late summer planting. A soil test can also help determine if phosphorus and/or potassium needs to be applied before planting. Phosphorus is a critical element to aid a new plant in establishing a good rooting system. The point here is that lime and fertilizer can represent a significant dollar investment and guessing as to the need and quantity can be expensive. So, as the saying goes; “Don’t guess, soil test”.
Weed control in an alfalfa stand really needs to begin before the crop is planted. Herbicide options in an established alfalfa stand are limited. Perennial broadleaf weeds and grasses should be managed and controlled in the crops previous to the alfalfa rotation. The general rule of thumb is that at least 95% of the weed control in a forage crop is provided by developing a dense, healthy stand that will not allow weeds to invade.
Just like other agronomic crops, weeds that emerge with the new alfalfa seedlings are the most destructive. The goal should be to maintain the new seeding relatively weed free for the first 60 days. These factors often make it necessary to use an herbicide with a pure seeding of alfalfa. There are a few herbicides that are commonly used when establishing a pure stand of alfalfa. Balan or Eptam can be used as pre-plant incorporated herbicides to provide control of annual grasses and some broadleaf weeds. Butyrac and Bromoxynil can be used to provide early post emergent control of some broadleaf weeds when weeds are no more than 2 inches tall. Clethodim and Sethoxydim or Sethoxydim plus Dash can control annual and perennial grasses in alfalfa. Prowl H2O provides residual control of most annual grasses and certain broadleaf weeds, but must be applied prior to weed emergence and the seedling alfalfa must be in the at least the 2nd trifoliolate stage of growth but not more than 6 inches tall. Imazethapyr and Imazamox control annual broadleaf weeds and suppress or control grass weeds, and must be applied when alfalfa is in the 2nd trifoliolate state or larger and when weeds are 1 to 3 inches tall or when rosettes are no more than 1 to 3 inches wide. More details are available in the 2012 Ohio and Indiana Weed Control Guide. Take the time to read and follow label directions. Herbicide use on forage crops such as alfalfa can involve harvest and grazing restrictions, in addition to specific limitations regarding the timing of the herbicide application.
Incorrect planting depth has been responsible for many poorly established stands of alfalfa or seeding failures. Alfalfa is a small seed and should not be seeded too deep. The recommended seeding depth for alfalfa is one-quarter to one-half inch deep. It is better to err on the side of planting shallow rather than too deep.
Another factor that works hand in hand with planting depth is correct calibration of the planter for seeding rate. The Ohio Agronomy Guide recommends seeding alfalfa at 15 lbs/acre of pure live seed for a pure stand. If a coated alfalfa seed is used, be aware that coatings can account for up to one-third of the weight of the seed. This can affect the number of seeds planted if the planter is set to plant seed on a weight basis. Seed coatings can also dramatically alter the flowability of the seed through the drill, so be sure to calibrate the drill or planter with the seed being planted.
Finally, use fungicide treated seed to provide protection against seedling diseases and make sure the seed is planted with the proper bacterial inoculum that has been maintained under conditions that ensure the inoculant is viable.
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