Monitoring Striga asiatica (Orobanchaceae) seedbank for eradication success

Abstract

To enable evaluation of eradication efforts for the parasitic plant Striga asiatica (L.) Kuntze, seed sachets were buried in perforated PVC canisters at 25 sites across the infested area in July 2016. The canister sites were selected based on the proximity to previous S. asiatica detections and cover the range of soil types and topographies associated within the eradication program treatment area. At each site the canisters received the same eradication treatments that were applied to the surrounding area. Site characteristics necessitated different combinations of false host (soybean), true host (corn), fumigant (dazomet), stimulant (ethylene) and herbicide treatments, to achieve a rapid decline in the soil seed bank.
The viability of retrieved seeds shows an accelerated decline (92.5 % to 6.5 % in four years) across all sites in response to the treatments irrespective of treatment combination used. The viability of seeds was found to vary across sites, burial depth and time. The information collected has provided valuable data for the eradication of S. asiatica in Australia and for evaluating the timing for
release of paddocks from active treatment.