Plants are exposed to large number of threats caused by herbivores and pathogens which cause important losses on crops. Plant pathogens such as nematodes can cause severe damage and losses in food security crops worldwide. Chemical pesticides were extendedly used for nematode management. However, due to their adverse effects on human health and the environment, they are now facing strong limitations by regulatory organisations such as EFSA (European Food Safety Authority). Therefore, there is an urgent need for alternative and efficient control measures, such as biological control agents or bio-based plant protection compounds. In this scenario, chitosan, a non-toxic polymer obtained from seafood waste mainly, is becoming increasingly important. Chitosan is the N-deacetylated form of chitin. Chitosan is effective in the control of plant pests and diseases. It also induces plants defence mechanisms. Chitosan is also compatible with some biocontrol microorganisms mainly entomopathogenic and nematophagous fungi. Some of them are antagonists of nematode pests of plants and animals. The nematophagous biocontrol fungus Pochonia chlamydosporia has been widely studied for sustainable management of nematodes affecting economically important crops and for its capability to grow with chitosan as only nutrient source. This fungus infects nematode eggs using hyphal tips and appressoria. Pochonia chlamydosporia also colonizes plant roots endophytically, stimulating plant defences by induction of salicylic and jasmonic acid biosynthesis and favours plant growth and development. Therefore, the combined use of chitosan and nematophagous fungi could be a novel strategy for the biological control of nematodes and other root pathogens of food security crops.

Pinna nobilis (Linnaeus, 1758) is the largest bivalve endemic to the Mediterranean. It is distributed in a wide range of coastal environments, including estuaries. Pinna nobilis has recently become a critically endangered species (with almost 100% mortality) along the entire Spanish Mediterranean coast. This may be due to coinfections caused by Haplosporidium pinnae and bacterial pathogens such as Mycobacterium spp. We extensively sampled P. nobilis from Mar Menor lagoon (SE Spain), a site where individuals still survive. Using conventional PCR, we found Haplosporidium spp. in 7.1% of mantle and faecal DNA samples in different individuals of P. nobilis. We identified and quantified Haplosporidium pinnae in P. nobilis using Sanger sequencing and qPCR. Faecal H. pinnae detection is non-invasive, unlike biopsies. Therefore, this non-lethal and non-invasive sampling method could contribute to the welfare of living populations, particularly in eutrophic environments, where they are prone to septicaemia. The use of faecal DNA analysis could be a major advance in epidemiology and recovery assessment studies of P. nobilis.