<unk> s are insecticidal and deterrent to a broad range of insects, including species in the Hemiptera, Coleoptera, Hymenoptera, Lepidoptera, and Blattodea, such as the bird cherry-oat aphid (genus Rhopalosiphum), large milkweed bug (Oncopeltus fasciatus), and American cockroach (Periplaneta americana). LC50 values of N-formylloline or N-acetylloline from grass seed extracts are 1-20 μg/ml for aphids and milkweed bugs and impair insect development and fecundity and cause avoidance of<unk> -containing grass tissues. However, results of feeding tests with grass extracts are occasionally difficult to interpret due to the presence of other endophyte<unk> s in these extracts, and the exact mechanisms of the insecticidal actions of the<unk> s are unknown. The<unk> s may be neurotoxic to the insects, and differences in the chemical groups at the C-1-amine result in different levels of insect toxicity; for example, N-formylloline (see Fig. 2), which occurs in higher concentrations in endophyte-infected grass plants, has greater insect toxicity than some other<unk> s, which occur at lower concentrations in the grass plant. Figure 2. N-formylloline, one of the most abundant<unk> s in endophyte-infected grasses.<unk>  bioactivities show some unexpected variability with variation in their concentration in grass tissues. For example, the tall fescue endophyte, N. coenophialum, has been associated with enhanced resistance to the migratory root-endoparasitic nematode, Pratylenchus scribneri. At low concentrations, N-formylloline serves as a chemoattractant for P. scribneri, but acts as a repellant at higher concentrations. However, ergot<unk> s also have repellent and immobilizing effects on P. scribneri, and an endophyte of perennial ryegrass lacking<unk> s, and genetically engineered to produce no ergot<unk> s, exhibits resistance to this nematode. Therefore, the relative importance of the<unk>  and ergot<unk> s to nematode resistance remains unclear. Many epichloae endophytes—including N. coenophialum symbiotic with Lolium arundinaceum (syn. Festuca arundinacea, tall fescue)—also produce ergot<unk> s that are toxic to mammalian herbivores. The ergot<unk> s occur at relatively low concentrations in the plant and are often difficult to detect analytically. By contrast, the<unk> s frequently accumulate to very high levels in grass tissues, and were, therefore, initially associated also with toxicity to mammalian herbivores. Specifically, the<unk> s were thought to be responsible for toxic symptoms called fescue toxicosis displayed by livestock grazing on grasses infected by N. coenophialum. However, subsequently it was demonstrated that only the endophyte-produced ergot<unk> s are responsible for the symptoms of fescue toxicosis (or summer syndrome), and not the<unk> s which, even at high doses, have only very small physiological effects on mammalians feeders. Another group of<unk> s, the senecio-type<unk> s, are produced by various plants and like the<unk> s, the senecio<unk> s possess a pyrrolizidine ring structure. Unlike the<unk> s, however, the senecio<unk> s exhibit strong hepatotoxicity, owing to a double bond between C-1 and C-2 in their ring structure. This double bond is absent in the<unk> s, explaining the lack of hepatotoxicity of this group of compounds. The<unk> s have been suggested to inhibit seed germination or growth of other plants (allelopathy), and to increase resistance of infected grasses against drought, but such effects have not been substantiated under more natural conditions of cultivation or in habitats.
Loline alkaloid
Alkylphenol
Biogenic amine
Polychlorinated naphthalene
Polycyclic aromatic hydrocarbon
Organobromine compound
Alcohols 
Organophosphate