Following the publication of the Scientific Opinion by EFSA's PLH Panel which assessed the risk to plant health posed by Xylella fastidiosa in the EU territory and evaluated risk reduction options, EFSA received a request for an urgent response to scientific and technical information provided by an Italian non-governmental organisation (NGO). The NGO claimed that X. fastidiosa is not the cause of olive tree decline in Lecce Province in Southern Italy, but only an endogenous element present in the trees that is not active or aggressive unless a series of fungi infect the plants and create the right conditions for the development of X. fastidiosa. The NGO also claimed that treatment possibilities do exist to treat such fungi including pruning of infected plants and soil treatment. EFSA has reviewed the submitted documentation and held a hearing with an expert on tracheomycotic fungi associated with olive decline in Apulia. EFSA concluded that currently there is no scientific evidence that tracheomycotic fungi are the primary causal agents of olive quick decline syndrome. EFSA recommended further research -based on pest biology and using replicated and well-designed field experiments - to provide insight into the sustainable management of this complex problem.