Open AccessMortality of Horn Fly (Diptera: Muscidae) Larvae in Bovine Dung Supplemented with Loline Alkaloids from Tall Fescue
Author(s) -
C. T. Dougherty,
F. W. Knapp,
Lowell P. Bush,
Jude E. Maul,
John van Willigen
Publication year - 1998
Publication title -
journal of medical entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 99
eISSN - 1938-2928
pISSN - 0022-2585
DOI - 10.1093/jmedent/35.5.798
Subject(s) - muscidae , biology , haematobia irritans , larva , stable fly , nuisance , stomoxys , french horn , myiasis , zoology , veterinary medicine , botany , ecology , psychology , pedagogy , medicine
Larvae of arthropod ectoparasites of livestock, such as the horn fly, Haematobia irritans (L.), may be exposed to acyl-loline alkaloids in dung of ruminant livestock ingesting herbage of the tall fescue (Festuca arundinacea Schreb.)-endophyte association [Neotyphodium coenophialum (Morgan-Jones & W. Gams) Glenn, Bacon & Hanlin comb. nov.]. Biological activity of alkaloid-supplemented bovine dung was assayed by growth, development, and survival of 1st instars of horn fly. An extract from tall fescue seed, containing N-formyl loline (NFL), N-acetyl loline (NAL), and loline (59:21:20 by mass, respectively) caused 100% mortality of horn fly larvae when dung was supplemented at > or = 100 micrograms/g. Probit analysis of data corrected for natural mortality indicated a LD50 of 30 micrograms/g (95% fidicial limits: 20-49 micrograms/g). When horn fly larvae were introduced to dung supplemented with up to 50 microM of acyl-loline derivatives, mortality of larvae varied significantly between alkaloids (P < 0.0001). Probit analysis indicated that NFL [LD50: 34 microM (95% fidicial limits: 3-53 microM)] was more toxic than NAL [LD50: 46 microM (0-83 microM)], and that loline hydrochloride was not toxic.