Distribution of potato cyst nematodes in England and Wales and the use of 1,3-dichloropropene for their control.
In the UK the most problematic pests of the potato crop are the potato cyst nematodes
Globodera rostochiensis and G. paUida. A structured survey of potato growing land in
England and Wales was undertaken to reassess their occurrence and distribution. peN
were present in 64% of sites sampled and of the populations found, 67% were G. pallida,
8% were G. rostochiensis and 25% contained both species. Just over 50% of the sites
sampled had a rotation length of 1 in 5 or less and cultivars with partial resistance to G.
paUida represented only 6% of the total number of plantings while those with resistance to
G. rostochiensis represented 43%. The results show an increase in the incidence of peN
compared with previous surveys and confirm the perceived shift towards G. paUida as the
Two field experiments were done to look at the integration of methods for the control of
peN and subsequent reduction in yield loss in situations of very high peN levels. The first
experiment assessed the use of 1,3-dichloropropene (1,3-D) with the granular nematicides
aldicarb, oxamyl and fosthiazate when growing the susceptible cultivar Estima. The second
experiment assessed the use of the resistant cultivar Sante with 1,3-D and oxamyl at full
and half-rates. 1,3-D significantly advanced emergence, increased percentage ground
cover, root invasion, yield, tuber numbers, and improved tuber size distribution. Nematode
multiplication was significantly reduced by fumigation in the first experiment.
The use of 1,3-D for the control of weed seeds was assessed and the results show a
reduction in germination of weed seeds in soil after fumigation. The use of 1,3-D for the
control of Rhizoctonia solani was also assessed and a trend in reduction in R. solani was
observed after fumigation although the differences were not statistically significant