Imazapyr and pyrithiobac movement in soil and from maize seed coats to control Striga in legume intercropping uri icon

abstract

  • Imazapyr and pyrithiobac dressed to seeds of imidazolinone-resistant maize effectively control Striga hermonthica (witchweed). The effects of the movement of these herbicides in the soil and in maize plants was measured on Striga germination and on legumes intercropped with maize. Striga seeds were killed when high rates of either herbicide percolated through simulated soil columns; almost no viable Striga seeds remained in the upper 10 cm, and >80% were killed at 30 cm. The herbicides applied to maize leaf whorls moved systemically out of roots, killing attached and germinating Striga. Sensitive crops (beans, cowpea, and yellow gram) were unaffected when planted at >15 cm. from maize coated with 0.4 mg a.i. pyrithiobac or 0.84 mg a.i. imazapyr seed(-1), but were severely inhibited when planted within 12 cm. Simple herbicide seed coatings are thus compatible with commonly used African intercropping systems, while facilitating maize growth and depleting the Striga seed bank. (C) 2002 Published by Elsevier Science Ltd.

publication date

  • 2002
  • 2002