Protecting pasture from predators

In NZ many common pasture plants are attacked by insects, damaging the plants themselves and causing economic losses. In response to these attacks plants produce a number of natural compounds in an effort to ward off predators; however, some of these compounds are toxic to the animals eating the plants, and may cause illness and death reports Scoop. The grasses do not produce the toxic compounds themselves; instead, they are produced by a type of fungus called an endophyte that is intimately associated with the grass (in what is called a symbiotic relationship that benefits both the fungi and the grass). These natural compounds, called alkaloids, produced by the endophyte, protect the plant from insect attack. Dr Brian Patchett from the Agriculture and Life Sciences Division at Lincoln University has undertaken research on the effect of particular alkaloids, known as lolines that are produced in meadow fescue grass containing the endophyte Neotyphodium uncinatum, on sheep, grass grubs and the Argentine stem weevil. "The main objective of my research was to investigate the concentration and distribution of loline alkaloids in 12 Cropmark Seeds meadow fescue breeding lines and the effects of these loline alkaloids on two common pasture insects in New Zealand, grass grub and Argentine stem weevil," said Dr Patchett. "My work showed that loline alkaloids produced by different parts of meadow fescue grass (leaves, stems, roots) containing the endophyte Neotyphodium uncinatum, were non toxic to sheep but toxic to the two important pasture insect pests, grass grub and Argentine stem weevil." These findings are significant in terms of developing an environmentally friendly and sustainable biological approach to the control of insect pests and related potential benefits to improving livestock performance in New Zealand.