Tolerance of AR1 <i>Neotyphodium</i> endophyte to fungicides used in perennial ryegrass seed production

Abstract

Perennial ryegrass (Lolium perenne) with the elite new AR1 endophyte (Neotyphodium lolii strain AR1) was treated with fungicides used for stem rust (Puccina graminis) control during head emergence, flowering and seed development. Field trials were carried out over two seasons, evaluating triazole and strobilurin fungicides and mixtures of these two groups of fungicides, applied either one or two times (Trial 1) or two or three times (Trial 2). Seed yields were measured and endophyte viability tested with grow-out tests of freshly harvested seed. Seed yields were increased by 76 to 83% with double applications, but not by single applications of azoxystrobin and epoiconazole in Trial 1. In the second year (Trial 2) seed yields were increased by between 13 and 27% with triple applications of these two fungicides and their mixtures. Endophyte viability was not affected by any of the fungicide treatments.

Epichloë Fungal Endophytes—From a Biological Curiosity in Wild Grasses to an Essential Component of Resilient High Performing Ryegrass and Fescue Pastures

“…When processed the seed must be packaged appropriately and stored at low temperature and humidity until ready to be sown. Quality control systems and monitoring of endophyte viability is required through the retail and distribution chain [ 130 , 466 , 467 ]. This has been agreed among suppliers of Epichloë endophyte products.…”

A fungal endophyte consortium counterbalances the negative effects of reduced nitrogen input on the yield of field-grown spring barley

“…2017). Rolston et al (2002) showed tolerance of a Neotyphodium endophyte to fungicides used to control stem rust ( Puccinia graminis ) in perennial ryegrass seed production; they found that endophyte viability was not affected by single, double or triple applications of azoxystrobin and epoxiconazole during the growing season. It is alternatively possible that the benefits were conferred early, even before fungicide application.…”

Ryegrass (<i>Lolium perenne</i>) seed yield response to fungicides a summary of 12 years of field research

“…Some fungicides used for stem rust control can affect endophyte (Neotyphodium lolli) transmission (Rolston et al 2002). Recommendations on fungicide(s) for seed crops should balance the benefits of protecting seed yield and the requirement for high levels of animal-safe endophyte in seed.…”

“…In years of epidemics, yield losses can be high, with Kerse & Ballard (1989) reporting four-to five-fold increases in seed yield using cyproconazole to control stem rust. New Zealand trials have reported seed yield responses from fungicides of 27 and 82% in consecutive years (Rolston et al 2002). Other foliar diseases that can reduce green leaf area during seed fill and that have been identified in Canterbury seed crops are crown rust caused by Puccinia coronata, brown blight caused by Drechslera siccans and Ramularia leaf spot caused by Ramularia pussilla (syn.…”