Seasonal Populations of Xiphinema Index in Vineyard Soils of North-Eastern Victoria, Australia

Systematic sampling of field populations of Xiphinema index in a vineyard in north-eastern Victoria indicates once-yearly reproduction in late summer. Few first stage larvae were recovered from the soil, but numbers of each successive stage were progressively higher. The proportion of adults reached a peak in summer and then declined rapidly. This was followed by increases in the percentages of successive larval stages. Under Victorian conditions X. index probably completes its life cycle in less than one year. Numbers of X. index and fluctuations in population were greatest at a depth of 15 cm, and were greater in a sandy loam than in a clayey soil. In laboratory experiments X. index survived for 69 days under a wide range of soil temperatures and moisture levels. Nematodes survived storage in soil at 37° and -11°, but 45° and -22° were lethal; few survived in either saturated soil or soil held at less than 74% R.H.