Experiments for immunization of Asclepias syriaca infected turfs

Abstract

In this article we publish information about the biology of Asclepias syriaca and the possible ways of protection against it based on field experiments. We also indicate the spread of Asclepias syriaca in Körös-Maros National Park and argue about the fate of these spots. Upon the results of our experiments we should make a protection plan against about 200 Asclepias-spots, in order to preserve the current state of nature of Körös-Maros National Park. We made botanical experiments on pastures and meadows around Biharugra. Relevés show that natural turfs keep shifting to anthropogenic vegetation, mainly around animal quarters. It is a highly important task to force back dangerous weeds. We can kill them off by adequate agricultural engineering, secondly by annual chemical weed control combined with cultivation and mechanical interventions. The cheapest and simplest method is prevention: to hinder the sedentation of seeds, and the elimination of sprouts. Besides intensive cultivation and mechanical intervention a good method for forcing back Asclepias syriaca is to plant leguminous crops or pastures with intensive mechanical mowing. We must make multi-year protection plans. A well timed disturbance of the soil or chemical weed control indicates the growth of root-buds, which results in the temporary spread of Asclepias syriaca, but on long term the sprout-colonies weaken due to the decrease of nutrients of roots. The best chemicals against Asclepias syriaca in monocot cultures are: bentazon, dikamba, triklopyr and fluroxipir and in slightly higher concentration sulfonil-carbamids. Other field herbicides are also effective. Herbicides are most effective when the assimilates are carried to the roots (before flower-formation and in fall, before winter dormancy). Older shoots carry the nutrients downwards while the young ones away from the roots. On uncultivated areas we van use non-selective herbicides, although it is much harder to eliminate undisturbed sprout-colonies. We must fight against Asclepias syriaca as best as we can, and we must find new methods.