Quantifying survival of nematodes in disturbed soil and under prolonged drying intervals

Abstract

Soilcontaminated footwear and equipment have been highlighted as a biosecurity risk for the entry of exotic unwanted organisms including nematodes into New Zealand Exotic plant parasitic nematodes (PPN) are of concern because of the risk they pose to commercially important crops and native plants Understanding survival probabilities of PPN in loose soil can assist in determining establishment probabilities if the soil is transported to new environments Two experiments were carried out (spring 2008 and summer 2009) using fieldcollected soil to determine nematode survival after 7 28 and 56 days of drying under ambient conditions in the laboratory Soil moisture at the beginning of the spring and summer experiments were ca 37 and 15 respectively Season appeared to be an important factor in the ability of the nematodes to survive desiccation with some plant parasitic taxa (Helicotylenchus and Criconematidae) present after 56 days in the summer experiment but none present beyond 7 days in the spring experiment Overall the reduction in total nematode numbers did not show a consistent pattern when compared to the day 0 samples with a reduction of 79 83 and 97 after 7 28 and 56 days of desiccation respectively for springcollected soil and 36 86 and 92 respectively for summercollected soil