Abstract: The effects of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) and fungi strains (Beauveria bassiana) were evaluated in laboratory assays against larvae of four xylophagous pests: the Asparagus moth Parahypopta caestrum, the European goat moth Cossus cossus, the pine longhorn Arhopalus syriacus and the black Buprestid Capnodis tenebrionis. Due to their biology and ethology, these insects may be included in the category of pests residing in cryptic habitats. The control of these species is very difficult, due to the inability of chemical pesticides to penetrate the cryptic habitats and reach the targets. The results showed that all the nematodes and fungal strains affected the insect survival. Steinernema feltiae and Beauveria bassiana showed the best performances. Considering the lack of effective chemical control means, the microbial control of the xylophagous pests by EPNs and EPFs reveals promising perspectives. Nematodes and fungi are able to penetrate the cryptic habitats because they are living organisms and may be horizontally transmitted by infected hosts. The distribution of EPF as preventive control method and the injection of EPNs suspensions to reach and infect the larvae inside the wood galleries can be a combined sustainable control system.