# Alfalfa production and blister beetles



## vhaby (Dec 30, 2009)

I picked this out of the Thread on *Best Grazing Grasses* and realized that my response was not related to that Thread and that a new Thread would be more suitable.

There may be other reasons alfalfa can't be grown, but the presence of blister beetles does not prohibit alfalfa growth. Soil type, improper site selection, strongly acidic subsoils, drought, improper fertilization (i.e. not applying boron after liming acid soils to pH 6.8 to 7.0), lack of equipment (few or no drills to seed alfalfa) and management experience etc. are better reasons that limit alfalfa production and growth.

I have observed no less than 25 experimental sites where various factors critical to alfalfa production were evaluated, some alfalfa plantings as large as 5 to 7.5 acres on-farm in the Rusk, Gregg, Smith, and Anderson counties (TX) and not one blister beetle was observed during the years 1986 through 2008. This does not mean that if large scale alfalfa production occurred in this region that blister beetle wouldn't show up.

Alfalfa can be grown on selected soils in east and east central Texas, east of I-35 if adeqate attention is given first to site selection- well-drained and aerated soil with subsoil pH levels at 5.5 and higher (2:1 water to soil pH measurement) to at least 4-ft deep. Preliminary site/soil selection can be made using USDA-NRCS soil desctiptions. Soil descriptions that contain the terms aqu, aquic, fluv, and hydr refer to water, wet soils, or frequently flooded soils. Also, slope can be evaluated from these same soil descriptions. After evaluating the site soil description, on-site soil sampling by one foot depths to at least 4-ft deep for pH analysis (depth samples taken from at least five random locations in the field) is needed to verify that the site is suitable for alfalfa production. If the site is suitable by these criteria, additional sampling to the 6-inch depth for the routine soil test while at the same time, sampling the 2- to 6-inch depth for boron analysis for fertility requirements is needed.

For a more detailed explanation go to:

http://http://overton.tamu.edu/files/2011/04/SelectingCoastalPlainSoilsforAlfalfa.pdf

One other advantage to growing alfalfa on limed acid soils- no cotton root rot was observed on any of these study sites.


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## panhandle9400 (Jan 17, 2010)

In most every producing states I have been in and have gotten hay from have or has had blister beetles. In our area we never worry too much about them , unless you let it go to mid to full bloom . What I have seen was the more bloom the more incects and bugs are drawn to it and then see blister beetles present during those times but never see them before bloom ? I send hay to Florida and to many horse farms never had any problems. I know east of me they are a problem. Prayers out to those who have been struck by a disaster , whatever sort flood,fire,drought etc. wish I had some of that water here !!!


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## vhaby (Dec 30, 2009)

Sorry, the link has an error. Access the site as follows:

Texas AgriLife Research & Extension Center at Overton

Click on Soil and Crops

and then click on Selecting Coastal Plain Soils for Alfalfa


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## hay wilson in TX (Jan 28, 2009)

Excellent information.

Something to consider is to raise alfalfa for grazing. The are numerous "Grazing" varieties but that is not necessary for grazing. 
My favorite alfalfa grazing system is the Dinner Time ( Noon) grazing system. Turn the animals in to graze a small patch just before going in for Dinner ( Noon Meal). Run then out after your noon knap. 
There are some excellent nondormant alfalfa varieties and they work well anywhere in Texas of for the Gulf States. No weather worries during harvest this way. Nice thing about this system is you do not NEED to supply water in the alfalfa patches. Just about eliminates bloat worries.

Alfalfa will grow HERE in winter, a majority of the winter growth is root growth, but there is more than enough top growth during the winter for grazing, of FD 6, 7, 8, & 9 alfalfa varieties. 
Winter grazing (February and March) does a good job of limiting the alfalfa weevil as a pest.

This is a good reason/opportunity to look at all your animals an extra two times a day.


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## hay wilson in TX (Jan 28, 2009)

This is from Kentucky, not because KY information is any better but because KY is The Horse State.
California has more horses than Kentucky and for sure more horses who major forage is alfalfa hay.

FORAGE 
Blister Beetles - What Hay Producers and Buyers Need to Know
By Lee Townsend

Here are some key points about blister beetles -

Blister beetles occur throughout the US - they are a potential problem in most all hay-production areas but risk varies greatly from area to area and year to year. 
Blister beetle toxicity is caused by cantharidin, a defensive compound that occurs in male blister beetles and is transferred to females during mating. If sufficient numbers of live or dead beetles are consumed, cantharidin irritates the intestinal and urinary tract and can lead to animal death, especially in horses. 
In Kentucky, blister beetles are active from mid-July into early September. They tend to cluster together, especially on flowering plants. 
Clear steps can be taken to eliminate or greatly reduce the potential of blister beetles in hay - 1) Use hay for horses that is cut before blister beetles become active; 2) if practical, cut hay before alfalfa or common flowering plants in the field are in bloom; 3) do not crimp condition hay if many plants are in the bloom stage. 
Blister beetles feed on a wide range of plants including alfalfa, clover, soybean, potato, tomato, and eggplant and are especially attracted to flowers. Like the Japanese beetle, feeding by a few blister beetles draws in more. Large numbers of beetles can cluster on small patches of flowering plants in an otherwise uninfested field. This can result in infested hay.

Fields should be checked visually for blister beetles before harvest. Especially flowering plants along field margins should be inspected. Sickle bar mowers and some circular or rotary mowers lay the hay down without crushing many beetles. As the hay cures, the beetles will leave.

Blister beetles have long (3/4" to 1-1/4"), narrow bodies, broad heads, and antennae that are about 1/3 the length of the entire body. The segment behind the head is narrow, so the beetle appears to have a "neck". The front wings are soft and flexible in contrast to the hard front wings of most beetles. The black blister beetle (jet black) and the margined blister beetle (black with thin gray stripe around wing covers) are common species in Kentucky.

Female blister beetles lay clusters of eggs in the soil in late summer. The small, active larvae that hatch from these eggs crawl over the soil surface entering cracks in search for grasshopper egg pods which are deposited in the soil. After finding the egg mass, blister beetle larvae become immobile and spend the rest of their developmental time as legless grubs. Blister beetles will not lay eggs in hay and the larvae do not feed on or develop in hay bales.

Blister Beetles in Alfalfa | University of Kentucky Entomology

Plus a couple of nontraditional state's information G4569 Blister Beetle Management in Alfalfa | University of Missouri Extension

http://www.ianrpubs.unl.edu/epublic/live/g1645/build/g1645.pdf

For the gullible, there are no hidden mountain valleys in Wyoming that does not have blister beetles.

Nor are there any hidden valleys in Rhode Island, any place on earth that has both flowering plants AND grasshoppers will have blister beetles.

The most common method to contaminate hay is to run the hay through a set of conditioning rollers. For several generations the folks in Kentucky smugly suggested they did not have them The Bugs because tit was a Western Problem. Then the conditioning mower appeared on the scene and for some strange reason they also had blister beetle poisoning.

The Western States bale their hay at night, and the beetles put up in the windrows and become baled in the hay. Some real horror stories there. The use of rollers squeezes the toxic blood from the beetle contaminating the hay and the dead beetles mostly fall to the ground.

It is probably true that the chicken or turkey is the only domestic animal dumb enough to eat a live blister beetle.


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## hay wilson in TX (Jan 28, 2009)

http://aces.nmsu.edu/pubs/_circulars/circ536.pdf is my favorite publication directed to the grower and livestock producer.


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## vhaby (Dec 30, 2009)

Now that we understand more about the blister beetle and how to manage around it, why is it that there is not more alfalfa being produced in Texas and in Coastal Plain states to the east? Technology is available for proper site selection on Coastal Plain soils and several excellent publications are available on how to grow alfalfa. Two of the best publications are:

http://www.agronomy.org/publications/alfalfa

Alfalfa Management in Georgia | CAES Publications | UGA

Your comments appreciated.


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## hay wilson in TX (Jan 28, 2009)

I suspect there is a mountain of misconceptions about the blister beetle. It is sad but from my experience even our Veterinarians are among the population that is ignorant about the life and times of The Bug. The horse owning members of our population are no more knowledgeable than the Veterinary corps. 
I do believe some Vets say that blisters beetles killed the horse even though it had been hit by a train doing 80 mph. They would if told their owners fed alfalfa hay to their trusty steeds.

Interestingly the sheep and goat owners expect their band to drop dead with little or no warning. 
It is a lot more common for a 100 lb goat to ingest the poison from 5 or 6 stripped beetles than it is for a 1,000 lb horse or cow to take in the poison from 50 or 60 striped beetles. The problem with a horse is it will die from colic at a less than lethal dose of the poison. For the record some of the dull colored blister beetles are only slightly toxic and can require the poison from 200 to 500 beetles for a fatal dose.

Here in the land of cotton root rot we have been assured alfalfa will *not* survive the year due to the Cotton RR.


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