Control of the carrot cyst nematode Heterodera carotae by tannin aqueous solutions.

A field trial was carried out to test the nematicidal activity of chestnut tannin aqueous solutions against the carrot cyst nematode Heterodera carotae. A soil naturally infested by the cyst nematode was subdivided in 2 m x 3 m plots distributed in a randomized block design with five replications/treatment. Plots were treated with tannin aqueous solutions at rates of 25 or 45 g/m2 in 4 l water/m2 applied in pre-emergence, 25 or 45 g/m2 in 4 l water/m2 applied in pre-emergence and 30 days after carrot emergence. Untreated soil and fenamiphos (60 l c.p./ha) treated plots were used as controls. Number and weight of marketable tap-roots from the central square metre of each plot were recorded at harvest. Cysts and number of eggs and juveniles/100 g dried soil were also determined. Cysts were extracted from soil samples, collected in each plot, by the Fenwick can. Data were statistically analysed and means compared by LSD’s test. On the base of results, the use of tannin should be favourably considered for plant protection against phytoparasitic nematodes although some aspects remain to be investigated.