Population changes of Xiphinema index in relation to host plant, soil type and temperature in Southern Italy

Abstract

Pots containing sterilized sand, loam or clay soil were planted with fig (Ficus carica L.) or grapevine (Vitis vinifera L. cv. Regina) and inoculated with female Xiphinema index Thorne et Allen. Half of the pots were maintained in a glasshouse (24-2S°C) and half in a screenhouse subject to seasonal and daily.fluctuations of the local (southern Italy) temperature and were sampled monthly for a period of two years to ascertain nematode population densities in the different treatments. Fig and grapevine were both good hosts for X. index and peak populations of about 200 nematodes/ml soil were reached about 15 months after inoculation in the glasshouse, and slightly lower peak populations but after a similar period in the screenhouse. Populations then declined. In the glasshouse, young females were present throughout the year and egg laying was virtually continuous. In the screenhouse, egg laying continued from May until the end of September, coinciding with the period when the mean air temperature was 15°C or above. It is estimated that there were just over two generations completed per year in the screenhouse (field conditions) and about four in the glasshouse. Because of the longevity of the females and the extended period of egg laying, all life stages were present at any time during the year. Population densities were similar in sand and loam, but populations on both fig and grapevine were generally lower and increased more slowly in clay soil.