the low productivity of yellow passion fruit is due often to the phytosanitary problems, being the collar rot caused by nectria haematococca, one of the main problems in the majority of the producing states of brazil. the disease control is basically preventive, avoiding the introduction of the pathogen in the area. so, the present work aimed at: a) evaluating the behavior of ungrafted yellow passion fruit cultivars 'afruvec', 'iac 275' and 'maguary' and 'afruvec' passion fruit grafted on five passiflora species (passiflora alata, p. maliformis, p. morifolia, p. mucronata and p. suberosa) in orchard where the disease is frequent; and b) evaluating the efficiency of chemical (copper oxychloride, prochloraz and thiabendazole) and biological products (trichoderma harzianum and trichoderma sp.) in the control of collar rot in 'afruvec' yellow passion fruit in field conditions. yellow passion fruit grafted on p. maliformis, p. suberosa and p. alata presented greater resistance to the collar rot in relation to the ungrafted yellow passion fruit. the chemical and biological products applied to the base of plants (500 ml of volume) in monthly or biweekly intervals were not efficient in reducing the disease occurrence.