regulates regulation of anatomical structure morphogenesis regulation of biological process involved in symbiotic interaction modulation of formation of structure involved in a symbiotic process formation of haustorium for nutrient acquisition biological regulation regulation of formation by symbiont of haustorium for nutrient acquisition from host Any process that modulates the frequency, rate or extent of symbiont haustorium formation for nutrient acquisition from host. The host is defined as the larger of the organisms involved in a symbiotic interaction. biological_process GO:0075045 Note that this term should not be used to annotate gene products of the host. It should only be used to annotate those gene products from the symbiont involved in this process.