The fungus should have a positive effect on crops, especially if you don't disturb the soil too much and break the very fine fungal threads.
Plants and mycorrhizal fungi have been forming symbiotic relationships for 400-odd million years - plants exude sugars through their roots which feed the fungi and the fungi in return provide plants with micro nutrients, minerals and moisture from beyond the normal reach of the plant roots. The fungus will also be producing glomalin which causes the soil to hold together and form crumbs rather than remain in fine particles (healthier soil, better moisture retention, improved drainage of excess water and easier for plant roots to penetrate).
Unless it's Honey Fungus you're lucky to have fungal growth, we've worked for seven years to encourage it to colonise our whole plot.
