Efficacy of Pesta granular formulation of Striga-mycoherbicide Fusarium oxysporum f. s p. strigae Foxy 2 after 5-year of storage uri icon

abstract

  • An important goal for mycoherbicide research and development is to produce a viable and consistently efficacious product with a long shelf life. The efficacy of 5-year-old Pesta granules of Fusarium oxysporum Foxy 2 in comparison to freshly prepared Pesta granules in controlling the root parasitic weed Striga hermonthica was studied. Pesta granules were made by encapsulating fresh chlamydospores of Foxy 2 in a matrix composed of durum wheat-flour, kaolin, and sucrose. Samples of Pesta granules were stored at 4 degrees C over a period of 5 years. Two g per pot (4 kg soil) of each granular preparation were incorporated pre-planting to sorghum together with Striga seeds. The application of the 5-year-old Pesta granules (2.4 x 10(5) CFU g(-1)) as well as the freshly prepared Pesta granules (1.5 x 10(6) CFU g(-1)) of Foxy 2 sharply reduced the total number of healthy emerged S. hermonthica shoots and/or caused severe disease on the emerged Striga plants compared to the control. None of the emerged plants reached flowering stage in Foxy 2-treated pots, whereas in the control treatment 19.2% of the Striga plants flowered. Maximum efficacy (i.e., 100% reduction in healthy emerged Striga shoots compared to the control treatment) of both Pesta preparations in controlling Striga was achieved, indicating similar potential of both old and fresh formulations. The result revealed that encapsulation of Foxy 2 into "Pesta" formulation did not adversely affect its virulence and efficacy even after 5 years of storage under cold conditions. This represents an important attribute to support wide-scale deployment, storage, handling and delivery of Striga-mycoherbicides Pesta technology in Africa.

publication date

  • 2008
  • 2008