An integrated strategy is required to control the sugar beet cyst nematode Heterodera schachtii which
causes severe yield losses in sugar beet. This study aimed at evaluating the effect of trap crop cultivation
(nematode resistant mustard, crop mixture (Trifolium alexandrinum L., Lupinus angustifolius L.,Pisum
sativum L., Phacelia tanacetifolia Benth., Guizotia abyssinica (L.F.) Cass., Avena strigosa Schreb., Vicia sativa
L.), straw mulch as control), nematicide application before sugar beet sowing and sugar beet variety
(susceptible, tolerant or resistant to H. schachtii) on population dynamics of H. schachtii and sugar yield.
Field experiments were conducted in eight environments (site
year) located in Northern Germany in
2012–2013 and 2013–2014. An insufficient trap crop dry matter yield (1.1–2.5 t ha1) mostly led to nonsignificant
trap crop effects on the nematode population whereas in one environment a high dry matter
yield of mustard (3.3 t ha1) resulted in a nematode reduction of 40%. However, there were no significant
differences to the straw mulch control. The nematicide application had no effect on nematode
reproduction. In contrast, population dynamics of H. schachtii were strongly influenced by the sugar beet
variety and the initial nematode population (PiSB). The highest reduction of 70% was achieved when a
resistant sugar beet variety was grown, while the tolerant and susceptible varieties increased the
nematode population in most environments. There was evidence that the sugar beet harvest date can
highly influence population dynamics of H. schachtii. Sugar yield was influenced by variety and PiSB, but
not by trap crop cultivation or nematicide application. Sugar yield decreased with increasing PiSB for all
varieties. The resistant and tolerant varieties did not differ in sugar yield and response to H. schachtii,
while the susceptible showed the steepest decline in sugar yield with increasing PiSB. The cultivation of
the resistant sugar beet variety can be clearly suggested with respect to sugar yield and nematode control
because all other tested factors failed to control the nematode population