fungus is capable of colonising roots and forming symbiotic relationship with many plants. Endophytes appear to enhance the growth of their plant host symbionts. Endophytes also provide their hosts with an increased resilience to both abiotic and biotic stressors such as drought, poor soils and herbivory. The increased growth and resilience is likely caused by the endophytes ability to improve plant nutrition or secondary metabolite production, as in the case of Phoma eupatoriis inhibition of the phytopathogen Phytophthora infestans. Endophytes accomplish this by increasing the uptake of valuable land limited nutrients from the soil such as phosphorus and making other plant nutrients available to plants such as rock phosphate and atmospheric nitrogen which are normally trapped in forms that are inaccessible to plants. Many endophytes protect plants from herbivory from both insects and animals by producing secondary metabolites that are either unappetizing or toxic to the herbivore. Increasingly there has been great importance placed on endophytes that protect valuable crops from invasive insects. One example of an endophyte-plant-insect interaction is located in the New Zealand grasslands, where endophytes, known as AR1 and AR37 are utilized to protect valuable ryegrass from the Argentine stem weevil but remain palatable to another important food source, livestock. There are several endophytes that have been discovered that exhibit insecticidal properties. One such endophyte comes from the Nodulisporium sp. which was first harvested from the plant Bontia daphnoides. Indole diterpenes, known as nodulisporic acids, have been harvested from this endophyte which have effective insecticidal properties against the blowfly larvae. There are many obstacles to successfully implementing the use of endophytes in agriculture. Despite the many known benefits that endophytes may confer to their plant hosts, conventional agricultural practices continue to take priority. Current agriculture relies heavily on fungicides and high levels of chemical fertilizers. The use of fungicides has a negative effect on endophytic fungi and fertilizers reduce a plant's dependence on its endophytic symbiont. Despite this, the interest and use of bio-insecticides and using endophytes to aid in plant growth is increasing as organic and sustainable agriculture is considered more important. As humans become more aware of the damage that synthetic insecticides cause to the environment and beneficial insects such as bees and butterflies biological insecticides may become more important to the agricultural industry. See also Biofertilizer List of endophytes Plant use of endophytic fungi in defense Arbuscular mycorrhiza Mycorrhiza Rhizobia References Microbial growth and