Plant parasitic nematodes (PPNs) undermine agriculture globally, through direct parasitism of crops and/or as vectors of secondary infections. The impacts are so severe and far reaching that quantifying the associated damage is virtually impossible. With the growing pressures on modern agriculture to increase productivity and to meet consumer demands, while facing limitations from increased biotic and abiotic challenge (despite slowing improvements in the development of new varietal germplasm), there is a widening gap between high yielding, high quality stock, and demand requirements. This study investigated the PPN populations in Northern Ireland agricultural land to enable identification of potential threats to plant-based agriculture systems from economically damaging species. Here, the extent of PPN diversity in Northern Irish agriculture was illustrated, with the identification of 18 different genera and the presence of statistically significant trends linking specific nematode presence and abundance with environmental and edaphic factors. Most notably, was the apparent significant increase in root knot nematode (Meloidogyne spp.) populations that were present at significantly higher incidences than those reported in the historical records. The detection of Meloidogyne minor in agricultural fields further strengthened the belief that this recently described species is in fact endemic to the British Isles. Potential nematode control management strategies were investigated and Northern Irish recommended cereal and pasture varieties were screened for the presence of naturally occurring resistance. The direct effects of several plant derived compounds and biostimulants on PPNs were investigated. Many of the compounds screened displayed attractive or repellent properties, while further analysis of ET and SA suggested Meloidogyne incognita juveniles possess memory and associative learning traits. In addition, the effects of biostimulant pre-treatment on crop plant health and resistance to nematode challenge was examined. Molecular-level impacts on the main plant defence signalling hormones (salicylate, jasmonate and ethylene) of biostimulant pre-treatment and! or 'priming' of plants during nematode challenge was assessed. Key defence related marker genes were compared at early stage infection time points (3 and 7 days post inoculation) in biostimulant pre-treated Arabidopsis thaliana.