Effect of growing legumes as pure and mixed crops on Otiorrhynchus ligustici L. (Coleoptera: Curculionidae) damage

Ivelina Mitkova Nikolova, Natalia Anastasova Georgieva and Viliana Marinova Vasileva

Abstract: A field trial was carried out at the Institute of Forage Crops, Pleven, Bulgaria to determine the effect of the growing legumes as pure and mixed crops on the damage of Otiorrhynchus ligustici L. The study was performed for the period 2015–2017 on sainfoin, birdsfoot trefoil and alfalfa stands (grown alone) and in mixtures with cocksfoot, sowed under cover of spring forage pea. In mixed crops, the O. ligustici damage expressed through the number of holes and furrows, as well as their length, was reduced by 22.7, 33.3 and 18.2%, respectively. Alfalfa was the most preference crop by the alfalfa snout beetle and birdsfoot trefoil was less affected. In addition, the distance of the spiral furrows from the root collar and legume root length increased in mixtures by 19.0 and 3.0% to the crops grown alone. The most strongly significant negative effect on the height of legumes had the length of the spiral furrows (-13.1). A less pronounced but significant negative effect had hole number on plant roots (-5.7). The technology of growing of legume crops had an impact on the injury on the plant roots by the soil-inhabiting insects as in mixtures, there are favorable conditions for both, development of plants and reducing the degree of damage.

Keywords: damage; legumes; mixtures; Otiorrhynchus ligustici

Date published: 2020-08-28