Dangerous Pasture and Hay Crops, Poisionous Plants, Toxic Plants

What can be done to avoid blister beetle problems?
*   Identify the species of blister beetles.
*   Grow your own alfalfa and maintain complete control over management practices, if possible.
*   Because blister beetle populations are not large until mid- to late summer, set aside first and often second cutting hay for use in feeding horses. Or consider purchasing first cutting hay from neighbors to use as horse feed.
*   Watch for beetles as you cut hay. Some species "swarm" in front of the harvester. Stop and let the beetles disperse before continuing.
*   Crimping and other conditioning increases the number of beetles that remain in the swath prior to baling. If possible, try to cut the alfalfa and put in swaths that can be straddled by the tractor to avoid crushing beetles in the windrow.
*   Eliminate weeds and cut the alfalfa before it reaches advanced bloom stages. Flowering plants attract the beetles that feed on alfalfa and weed pollen.
*   Insecticide treatments are available but must be applied with preharvest intervals in mind. If you treat with insecticides, be sure to allow enough time so that dying beetles fall out of the canopy to the ground where they burrow into the soil. Do not treat fields at peak bloom to avoid bee kills and losses to other beneficial species.

Because the larvae of many blister beetles in the genus Epicauta eat only grasshopper egg pods, these blister beetles are often associated with grasshopper outbreaks. Alfalfa grown near rangeland has a greater likelihood of blister beetle infestation.

Blister beetles are especially attracted to alfalfa and weeds (e.g., goldenrod) during bloom.

Guidelines for insecticide use in alfalfa are published annually in the High Plains Integrated Pest Management Guide. To purchase a copy, call the Colorado State University Cooperative Extension Resource Center, (970) 491-6198.

Insecticides are hazardous to pollinators, especially honey bees. Read, understand and follow all label directions, including pollinator protection statements.

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TALL FESCUE
Festuca arundinacea (grass family)
TOXICITY RATING: Moderate to high, depending upon individual circumstance.
ANIMALS AFFECTED: Horses, cattle, possibly other ruminants.
DANGEROUS PARTS OF THE PLANT: Seed head, stem and leaf sheath.
CLASS OF SIGNS: Reproductive problems, "poor doers", lameness, dry gangrene, fever, death.
PLANT DESCRIPTION: This grass (fig. 15), often cultivated in wet pastures for forage or for turf, is a perennial, 3 to 4 foot tall clump grass with medium-wide leaves that are rough-ribbed on top. It has no rootstocks (rhizomes). The heads are open and many-branched. Escaped plants may be found along roadsides and in waste areas.
SIGNS: Toxicity is the result of an endophytic ("in
side the plant") fungus, Acremonium coenophialum, which is believed to enable the grass to be more hardy and outcompete other grass species. The grass itself is not toxic. The fungus is passed in the seed, and is not transmitted directly from plant to plant. In horses, pregnant mares are most at risk when eating fescue, since the alkaloids produced by the fungus inhibit prolactin release. Mares will have an increased risk of prolonged gestation, abortion, stillbirth, dystocia (difficult birth), foal mortality, retained or thickened placenta, no milk, and mare death (in foaling, or from a retained placenta). Additional note: Fescue can accumulate nitrates under conditions of overfertilization (see the section on oats for more information on nitrate toxicosis).
FIRST AID: There is only supportive and symptomatic treatment once signs appear. A veterinarian can advise on treatment of more severely affected animals. Pregnant mares will be likely to need assistance when foaling and in the post-foaling period. Foals that survive will require supplemental colostrum. Management and prevention are the best means to minimize losses.
SAFETY IN PREPARED FEEDS: The toxin remains active in hay.
PREVENTION: Fungicides do not work, so animal and pasture management are the only viable alternatives. Pastures can be tested for the presence and degree of fungal contamination, and reseeding may be needed. If reseeding the pasture is not an option, keeping the pasture short will prevent seed formation. Feeding other forages, such as other warm season grasses or legumes, will be of benefit. Fescue pastures can also be diluted with legume planting (red or white clover). Heavy fertilization may make the problem worse, especially in cattle. If fescue has to be used for mares, at least avoid feeding fescue hay or pasture during the last 30 to 60 days of gestation to minimize problems. Endophyte-free strains of fescue exist, although they do not grow as well as tall fescue with endophyte.

JOHNSON GRASS
Sorghum halepense (grass family)

TOXICITY RATING: Moderate to high.
ANIMALS AFFECTED: All types, especially ruminants.
DANGEROUS PARTS OF PLANTS: Leaves and stems, especially young plants.
CLASS OF SIGNS: Breathing problems, staggering, severe anxiety, convulsions, coma, death (may be very sudden).
PLANT DESCRIPTION: Johnsongrass , a coarse perennial grass, produces large, scaly rootstocks and grows in dense stands up to 6 feet high. Seed heads are large and loose. This plant grows commonly in the fields, fencerows, and ditch banks of the southern part of the US and is rapidly spreading northward. Once grown for dike stabilization or for hay, it is now classified as a "noxious" weed.
SIGNS: The toxic signs resulting from ingestion of Johnsongrass are due to the presence of cyanide in the leaves and stems. This toxicity is identical to that resulting from the ingestion of wilted or damaged cherry leaves. In normal, healthy Johnsongrass plants, the levels of free cyanide are low, and the plant can be consumed safely. Other members of this grass genus have been bred as grain or forage plants (milo, Sudan grass, etc.) and also have the potential to produce cyanide, although not as much as Johnsongrass. The young shoots are the most dangerous, and when wilted, trampled, herbicide treated or frost damaged, a great deal of free cyanide is liberated in the leaves. Upon ingestion, the animals quickly develop signs related to cyanide poisoning. Mature plants have much lower toxicity, and well-cured hay is relatively safe for consumption.