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Nematode destroying microbes and the decline of potato cyst nematodes - HH3110SPO

This one-year proposal aims to assess whether nematophagous fungi and the bacterium, Pasteuria penetrans are able to significantly increase the rates of decline of potato cyst nematode (PCN) populations between potato crops. Recent research on PCN conducted within DEFRA project HP0115, indicates that PCN eggs within cysts are susceptible to fungal attack in soil. This finding suggests that PCN populations may be further reduced between potato crops and provide the potential for reducing recommended crop rotations on nematode infested land. The main nematophagous fungi affecting PCN populations are Pochonia chlamydosporia, Plectosphaerella cucumerina and Paecilomyces lilacinus, which caused significant (>40%) reductions in the number of eggs surviving in soil after potatoes were grown in laboratory experiments.

Two stages of PCN, eggs and second-stage (infective) juveniles survive in soil between potato crops. Nematode parasitic fungi and bacteria in soil will be investigated in laboratory tests and in the field to assess their impact on PCN abundance under different break crops.

PCN is the major pest on potatoes in the UK and growers use nematicides on infested land to reduce PCN populations before susceptible crops are grown. There are no effective resistant potato varieties that are effective against Globodera pallida, which is the major potato cyst nematode species in the UK. Nematicides include some of the most toxic products used in agriculture and there is a need to develop alternative more sustainable control measures for these pests in line with DEFRA policy for more environmentally benign pest control. The work proposed would contribute to the development of an integrated management strategy for PCN that would depend less on the use of nematicides.
This short (one-year) proposal aims to establish proof of the concept that microbial agents in soil may significantly reduce the number of PCN eggs and juveniles surviving in soil following a potato crop. This will be tested within the following objectives:
1. To evaluate the effect of different rotational crops such as brassicas, oilseed rape, sugar beet, cereals and a potato trap crop on the abundance of P. chlamydosporia, P. lilacinus, and P. cucumerina and their parasitism of PCN eggs in cysts in soil in controlled conditions.
2. To test different isolates of P. penetrans for their ability to attack different populations of G. rostochiensis and G. pallida.
3. To estimate levels of egg parasitism of PCN from May to October in at least two field soils following potato crops in 2002.
Project Documents
• Final Report : Nematode destroying microbes and the decline of potato cyst nematodes   (92k)
Time-Scale and Cost
From: 2003

To: 2004

Cost: £74,011
Contractor / Funded Organisations
Rothamsted Research (BBSRC)
Biological Control              
Fields of Study