THE SYNERGISM OF SOIL SOLARIZATION WITH FUMIGANT NEMATICIDES AND STRAW FOR THE CONTROL OF HETERODERA CAROTAE AND DITYLENCHUS DIPSACI

N. Greco, T. D'Addabbo, V. Stea, A. Brandonisio

Abstract


The synergism of soil solarization with applications of reduced rates of 1,3 D and dazomet and soil incorporation of wheat straw on the control of Heterodera carotae on carrot and Ditylenchus dipsaci on onion was investigated in 1990-1991 in six field trials in Italy. Fumigations with 25 or 50 1 1,3 D/ha followed by four or eight week solarization periods improved the control of H. carotae compared with either method alone, resulting in the near eradication of the nematode from the top 30 cm soil and suppression of carrot feeder root infestation. Significant increases in carrot yields were obtained with 50 1 1,3 D/ha in combination with soil solarization. Similar levels of egg mortality of H, carotae were obtained by a combination of soil application of 50 or 100 kg dazomet/ha and soil solarization, although the treatment had no effect on carrot yield and root infestation. More onion plants survived Ditylenchus dipsaci infestation and larger marketable yields of onions were obtained with a combination of soil solarization with 25 or 50 1 1,3 D/ha. Except for an application of 50 kg dazometh followed by eight week solarization, both solarization periods and all rates of dazomet, alone or in combination, fenamiphos at 10 kg/ha and 1,3 D at 250 l/ha suppressed nematode infestation and increased onion yield. Soil incorporation of 5 and 10 t wheat strawha, or 5 t straw/ha followed by eight week solarization, also reduced nematode infestation and increased onion yield.

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