Preliminary results regarding the attack produced by the species Diabrotica virgifera virgifera le conte on maize, depending on the chemical treatment applied to the soil, in the conditions of Central Moldova

Abstract

The species Diabrotica virgifera virgifera Le Conte (western corn rootworm) belongs to the order Coleoptera, family Chrysomelidae. It originates from North America and entered in Europe in 1992, in Yugoslavia. It entered in Romania in 1996, when three specimens were recorded in Nădlac (Arad county), and since then the range of the pest has continuously expanded (Manole, 2017). To reduce the spread of this pest, it is recommended to avoid monoculture and practice rotation. It can reduce the root attack to a minimum level, the larvae not being able to survive in soils cultivated with other plants (Ciobanu, 2009). The most common strategies used to protect maize roots against the pest Diabrotica virgifera virgifera are the application of an insecticide to the soil at seeding and the use of an insecticide in the seed treatment (Sutter et al., 1990). The average number of larvae per plant varied from 1 to 5, the fewest larvae being recorded in the variant where the granular insecticide Force G was applied to the soil at a dose of 15 kg/ha. The frequency of swan neck ranged from 0% to 58%. The attack produced by adults on the leaf recorded frequencies between 32% and 66%, and on maize silk, the attack was 100%. The average number of adults per plant was between 9 and 10.