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The aphid Aploneura lentisci is widespread in Australia and New Zealand, living all year round on roots of its secondary grass hosts. The fungal endophyte (Epichloë festucae var. lolii), strain AR37 in Lolium perenne is known to greatly reduce populations and was a likely reason for the superior growth and persistence of this association previously observed in the field. Aphid populations were quantified in a field trial near Ballarat, comparing yields of perennial ryegrass infected with eight different endophyte strains and an endophyte-free (Nil) control in a common ryegrass background (Grasslands Samson (G. Samson)). AR37 and another endophyte strain, AR5, had significantly fewer aphids than all other endophytes. These differences were significantly related to yield increases taken before and after sampling that persisted until the end of the trial. In a pot trial comparing commercially available ryegrass-endophyte combinations with equivalent Nil controls, aphid numbers were lower on G. Samson AR37 and Banquet II with AR5 (Endo®5) than on all other cultivar-endophyte combinations. Compared with Nil controls, the common toxic strain in G. Samson, and two strains in Trojan also reduced aphid numbers. The AR5 endophyte produces the alkaloid ergovaline but high concentrations of this in roots of potted plants could not account for differences in root aphid numbers. Root concentrations of epoxyjanthitrems, the only known alkaloids produced by AR37, were low and unlikely to be the cause of resistance to A. lentisci. An aphid, Aploneura lentisci , that feeds on grass roots is widespread in pastures in New Zealand and Australia. This paper reports data confirming that perennial ryegrass infected with a strain of Epichloë fungal endophyte, AR37, is highly resistant to this aphid and shows that another endophyte strain, AR5, gives the same level of control. Suppression of high aphid populations by these endophytes in the field at Ballarat resulted in a 37% increase in pasture production over endophyte-free ryegrass over a 5-month period. [ABSTRACT FROM AUTHOR]

Widespread infection of Epichloë occultans in annual ryegrass in Australia suggests that infection provides its weedy host, Lolium rigidum, some ecological advantage. Initial studies determined the distribution and profiles of known Epichloë alkaloids (epoxy-janthitrems, ergovaline, lolines, lolitrem B, and peramine) in plant extracts using a combination of GC-FID and HPLC techniques utilizing a single accession of Australian L. rigidum. However, the lolines N-acetylnorloline (NANL) and N-formylloline (NFL) were the only alkaloids detected and were highly concentrated in the immature inflorescences of mature plants. Additional glasshouse studies subjected a wide range of Australian L. rigidum haplotypes and international annual Lolium accessions to a suite of analyses to determine alkaloid levels and profiles. Again, NFL and NANL were the key lolines produced, with NFL consistently predominating. Considerable variation in alkaloid production was found both within and between biotypes and accessions evaluated under identical conditions, at the same maturation stage and on the same tissue type. The pyrrolopyrazine alkaloid peramine was also present in 8 out of 17 Australian biotypes of L. rigidum and 7 out of 33 international accessions infected with Epichloë spp.; the highest peramine concentrations were observed in seed extracts from L. rigidum collected from Australia. This study represents the first report of alkaloids from a geographically diverse collection of annual ryegrass germplasm infected with Epichloë spp. when grown under identical controlled conditions.