Predatory Insects and Spiders From Suburban Lawns in Lexington, Kentucky

Predatory arthropods were caught in pitfall traps in suburban lawns in Lexington, Kentucky. The relative abundance of species of Lycosidae, Carabidae, and Staphylinidae was compared in Kentucky bluegrass and tall fescue turf. Nine species of Lycosidae were collected from both the bluegrass and tall fescue lawns. More species or phena of Carabidae were collected from bluegrass than from tall fescue turf. More than 40 species or phena of staphylinids were collected from each grass habitat. Both Kentucky bluegrass and tall fescue are inhabited by an abundant and diverse array of predatory arthropods

Ergovaline and Ergovalinine and Tall Fescue Content of Pastures in Central Kentucky

Kentucky has \u3e 2Mha of tall fescue (Festuca arundianacea Schreb.) grown mainly for livestock consumption. Many alkaloids in tall fescue are produced in a mutualistic association between tall fescue and an endophytic fungus (Neotyphodium coenophialum) (Long et al., 2002). Ingestion of tall fescue by livestock may depress reproduction and growth (Schultz & Bush, 2002). Not all Kentucky fields of tall fescue are thought to be infected with endophyte, but forage samples from all surveyed pastures had measurable ergopeptine alkaloids. Therefore, it is reasonable to assume that some of the tall fescue plants in these fields were infected. We estimated tall fescue content and evaluated ergopeptine alkaloids in tall fescue monocultures and composite pastures of several central Kentucky horse farms

INVESTMENT ANALYSIS OF REPLACING ENDOPHYTE-INFECTED WITH ENDOPHYTE-FREE TALL FESCUE PASTURES

Cattle consuming tall fescue pastures infected with the endophyte Neotyphodium coenophialum often suffer physiological disorders that reduce animal performance. One solution is to replace endophyte-infected tall fescue pastures with an endophyte-free mixture. A benefit-cost analysis was conducted to determine the profitability of pasture restoration. The profitability of this action depends on the percentage of endophyte in existing pastures, the discount rate, and the stand life of the endophyte-free tall fescue variety. Our benefit-cost analysis results indicate that in order for pasture replacement to be profitable, the existing pastures must be infected with more than 16.1% of the endophyte, assuming the stand life of endophyte-free tall fescue is 12 years and the discount rate is three per cent. Additionally, a sensitivity analysis was conducted to determine the impact on the critical infestation level when the following parameters are changed: the discount rate, the baseline calving rates, and the pasture stand life. This research provides farmers with a practical investment analysis model for replacing endophyte-infected with endophyte-free tall fescue pastures.Land Economics/Use,

An examination of the complex ecological role of tall fescue in grassland restoration

Tall fescue (Schedonorus arundinaceus (Schreb.), an exotic-invasive, cool-season grass has invaded millions of acres of grassland in the United States. Tall fescue\u27s dominance can be attributed, in part, to a fungal endophyte (Epichloë coenophiala) that confers fitness benefits to the grass, and which lives symbiotically within the grass host. With invasion into native grasslands, tall fescue alters litter production, changes composition and structure of vegetation, and modifies fire behavior. This thesis presents results from two studies on the complex role of tall fescue in Iowa grasslands. In the first study, I investigated how grassland management with fire and grazing influences tall fescue cover and litter dynamics. From 2012-2014, three fire and grazing treatments were applied to pastures with a mixture of tall fescue and other native and exotic plants in the Grand River Grasslands of Iowa and Missouri. We hypothesized that the fire-grazing interaction (a.k.a. patch-burn grazing) would reduce tall fescue cover more than fire or grazing treatments applied independently. We also hypothesized that because tall fescue may impede fire movement across the landscape, litter depth and woody plant cover would be positively correlated with the presence of tall fescue following use of this management technique. Over the three years of the study, tall fescue cover was not reduced as a result of the treatments, and there was only a weak positive correlation between tall fescue and litter cover. No correlation was found between tall fescue and woody plant cover. Years-since-fire had the greatest effect on litter dynamics – regardless of tall fescue abundance at the site - and the patch-burn grazing treatment had the most heterogeneous litter depths within each year. Our findings suggest that patch-burn grazing can benefit livestock producers and wildlife in fescue-invaded pastures, but it is not sufficient to reduce tall fescue cover. In the second experiment, we examined how invasive, exotic grasses like tall fescue may be contributing to the decline of grassland butterflies through alterations in forage quality. Alkaloids produced by the endophyte are known to be toxic to some foliar-feeding pest insects, but effects of the endophyte on non-pest insects such as butterflies are relatively unknown. We examined growth and survival parameters of tawny-edged skippers (Polites themistocles) that were reared on endophyte-infected tall fescue (E+), endophyte-free tall fescue (E-), and Kentucky bluegrass (KBG). Results showed that the endophyte did not affect growth and survival of larvae compared to uninfected tall fescue, even though significant amounts of loline alkaloids (average 740 ppm) were measured in endophyte-infected plant material. Larvae feeding on KBG grew faster with greater survival rates than larvae on both tall fescue treatments. These results confirm that tall fescue invasion and dominance may be deteriorating the quality of grassland habitats for native pollinators; however, this effect does not appear to be linked to endophyte infection

Endophyte in Tall Fescue: Impact on Horses and Cattle

Tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] is an introduced cool-season perennial grass from Europe. Originally imported for regularly flooded pastures, tall fescue is now widespread across the United States due to its adaptability of a wide range of soils and climate. Kentucky 31 tall fescue is the ecotype discovered in 1931 by E.N. Fergus, which launched its popularity as a dependable, adaptable, and palatable pasture crop. In the mid-1970s, the negative effects caused by consuming tall fescue were termed fescue toxicosis. The source of fescue toxicosis was not identified until Charles Bacon first reported evidence of an endophytic fungus in tall fescue. The endophytic fungus, later identified as Neotyphodium coenophialum, has a symbiotic relationship with tall fescue. Tall fescue provides nutrients for the endophyte, while Neotyphodium coenophialum produces toxic alkaloids that protect the plant from herbivory, diseases, and gives the plant its tolerance of many environmental stresses, including drought. The three main classes of alkaloids that potentially cause fescue toxicosis are ergot, pyrrolizidine (lolines), and pyrrolopyrazine (peramine) alkaloids (Schultz). Ergot alkaloids are made up of three families: ergopeptines, ergolines, and clavines. Ergovaline, an ergopeptine, is the primary alkaloid toxin affecting grazing mammals. Neotyphodium coenophialum does not change the appearance of the plant. Therefore, the endophyte is only detected by laboratory analysis. Endophyte-infected tall fescue spreads solely by seed. Due to the vast acreage of tall fescue, fescue toxicosis is the top toxicity problem of large animals in the United States

Perennial Warm-Season Grass Forages Impact on Cow-Calf Profitability in the Fescue Belt

Incorporating a perennial warm- season grass (WSG) into tall fescue (Lolium arundina-ceum [Schreb.] Darbysh.) forage systems in the fescue belt can help avoid the effects of fescue toxicosis on beef cattle (Bos taurus) reproduction and animal performance and provide forage during summer when fescue production is low. However, little information is available on the economics of incorporating WSG into fescue-based forage systems. We developed a simulation model to compare profitability of three forage systems—100% tall fescue, 70% tall fescue/30% bermudagrass (Cynodon dactylon), and 70% tall fescue/ 30% switchgrass (Panicum virgatum)—while also comparing spring- and fall-calving sea-sons on model beef cattle cow-calf operations in the fescue belt. Incorporating switch-grass increased profitability of tall fescue forage systems in both spring- and fall- calving herds, while adding bermudagrass increased profitability in spring-calving herds but not fall-calving herds. Spring-calving herds benefited the most from incorporating WSG, with profitability increases of $877 and$372 per hectare for switchgrass and bermudagrass, respectively, over the 100% tall fescue system. The order of profitability of forage systems did not change with randomly simulated decreases in rainfall and associated increased hay- feeding days, but with annual rainfall \u3e88% of the long- term average, fall- calving 100% tall fescue was more profitable than fall- calving 70% tall fescue/30% bermuda grass. Of the scenarios modeled, the results of the simulation suggest that a profit-maximizing producer would utilize a 70% tall fescue/30% switchgrass forage system

A Review of the Agronomic Characteristics of Endophyte-Free and Endophyte-Infected Tall Fescue

Agronomic differences between endophyte- (Acremonium coenophialum Morgan Jones and Gams) free and endophyte-infected tall fescue (Festuca arundinacea Schreb.) exist, and should be considered when implementing a management strategy. Although dry matter yield of tall fescue does not generally appear to be influenced by endophyte infection status, endophyte infection has been shown to improve seedling performance and survival, is associated with insect and nematode resistance, drought resistance, improved nitrogen assimilation, and higher seed set. Considering all biologically valuable characters of the endophyte-tall fescue relationship, survival of endophyte-infected tall fescue is probably better than that of endophyte-free tall fescue, especially in drought- or heat-stressed environments. Despite problems which growers have reported in establishing stand; of endophyte-free tall fescue varieties, there is still a decided advantage to seeding endophyte-free tall fescue because of improved livestock performance. However, greater attention to management is needed, particularly during the establishment year. Good seedbed preparation, including fertility improvements, should be stressed for endophyte-free tall fescue. Since endophyte-free tall fescue seedlings are not as vigorous as endophyte-infected tall fescue seedlings, using other grasses as nurse crops, or seeding with clovers, is not recommended when establishing new stands. Environmental or imposed stress on newly established endophyte-free tall fescue stands should be avoided by selecting optimum planting dates, and limiting livestock access. Top growth should not be grazed or clipped shorter than 3-4 in. (7-10 cm) during the first year of growth

Effects of Fescue Toxicosis on Bovine Acrosomal Integrity and Semen Cryopreservation

Tall fescue is the most widely used cool-season perennial bunchgrass in the southeastern United States and serves as forage for approximately 8.5 million cattle. Through a mutualistic relationship with the endophyte Epichloë coenophiala, tall fescue is bestowed insect resistance and disease, drought, and grazing tolerance. In spite of these desirable agronomic traits, the endophyte produces ergot alkaloids that are harmful to the physiology of animals consuming tall fescue. Accumulation of ergot alkaloids in animal systems results in a syndrome known as fescue toxicosis. Among other symptoms, reproductive inefficiencies are reported for beef cattle consuming toxic tall fescue. The objectives of this research were to assess the influence of toxic tall fescue consumption on bull sperm by evaluating acrosomal integrity and survival of spermatozoa following cryopreservation. Semen was collected and fixed from bulls that were either fed a ration containing toxic or nontoxic tall fescue seed or grazing toxic or nontoxic tall fescue pasture. Fluorescent-labeled peanut agglutinin was used to evaluate sperm acrosomal integrity. According to our methodologies and data, subtle, if any, differences due to treatment were detected. Semen was also collected, extended, and frozen from bulls grazing toxic or nontoxic tall fescue. Differences due to treatment post-thaw were detected for sperm progressive motility. Significant treatment by day interactions were detected for sperm concentration, motility, total motile sperm per dose, and total progressive motile sperm per dose post-thaw. Our results indicate that acrosomal integrity is not greatly affected by fescue toxicosis, and that grazing toxic tall fescue negatively impacts spermatozoa physiology as measured by survival of sperm following cryopreservation

Nematode resistance in tall fescue

Tall fescue, Festuca arundinacea. an important forage grass in the southeastern United States, is frequently infected with Acremonium coenophialum. an endophytic fungus associated with fescue toxicosis in livestock. Endophyte-free (E-) tall fescue is more difficult to establish and are not as resistant to environmental stress and pests as endophyte-infected (E+) tall fescue. Greenhouse trials were conducted on three species of plant-parasitic nematodes with different feeding patterns to compare populations on E+ and E- tall fescue. Presence or absence of the endophyte was determined with PAS-ELISA. After 15 weeks, numbers of Pratylenchus scribneri. a migratory endoparasite, were significantly higher on E- than on E+ tall fescue roots. After 8 weeks, numbers of egg masses and eggs of Meloidogyne graminis, a sedentary endoparasite, were significantly higher on E- than on E+ tall fescue. Numbers of Helicotylenchus pseudorobustus, an ectoparasite, were not significantly different on E- and E+ tall fescue after 8 weeks. Numbers of an undescribed species of Meloidogyne, which is parasitic on legumes, were unaffected by presence of E+ or E- tall fescue in the rhizosphere. Results of these experiments suggest that substances within E+ tall fescue roots may be inhibitory or toxic to some plant parasitic nematodes. These substances have not been identified. A bioassay using P. scribneri as the test organism was developed to determine toxicity of alkaloids and other compounds isolated from E+ tall fescue. Nematodes were exposed to test compounds for 48 hours; survivors were allowed to exit the test system for 72 hours and were counted. Ergotamine tartrate was more toxic to nematodes than saturated pyrrolizidines