Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Biological control of common cocklebur by Alternaria helianthi.

Abstract

Greenhouse studies were carried out on the use of Alternaria helianthi as a biological control agent against Xanthium strumarium. A. helianthi conidia grown at 18°C were the most virulent in producing diseases on hosts. The dew period requirements could be reduced to 9 hours with an unrefined maize oil emulsion and the dew period could also be delayed for 24 hours after application. A. helianthi was effective in the control of imazaquin-, MSMA- and metribuzin-resistant biotypes of X. strumarium. A. helianthi was most effective on young seedlings (2- to 6-leaf stage), but higher doses (>50 000 conidia/ml) could also control older seedlings.