Effect of orchard site and climatic conditions on plant nematode density levels

Phytoparasitic nematodes are commonly found in the soil and their presence can lead to plant diseases, weaker growth, reduced yields and lower fruit quality. A study conducted in 2006–2009, involving the monitoring of climatic conditions, identified the influence of precipitation and temperature on the number of nematodes, in 7 sites within a cherry orchard. Soil samples to assess nematode populations were taken from 7 sites that differed in terms of cultivation and age: 5 cherry orchards established in different years. Not all nematode taxa responded in the same way to temperature increase. Members of the families Belonolaimidae, Trichodoridae and the genus Aphelenchus increased in number with rising temperatures. The negative water balance limited the number of nematodes in the soil in the layer up to 30 cm, whereas the increase in soil moisture had a positive effect on the development of Paratylenchus spp., and mebers of the family Hoplolaimidae and Heterodera. The largest total number of nematodes was found on the strip cultivated with agricultural crops after orchard liquidation. However, parasitic nematodes accounted for were at low levels (17%). The size of fruits from trees growing on sites with a large number of nematodes decreased with a simultaneous increase in total soluble solids and fruit firmness.