The perspectives to use an organic extract from the Fabaceae family to control the maize leaf weevil (Tanymecus dilaticollis gyll) at the maize crop in Romania

Abstract

In this paper, we present results of two years study, in the field conditions, at NARDI Fundulea, located in the southeast of Romania, concerning the effectiveness of the biological control of the maize leaf weevils (Tanymecus dilaticollis Gyll) at maize crops, with organic insecticide on a base of plant extracts from the Fabaceae family (0.3 %) applied both, like seed coating and foliar spray. It has assessed weevils attack intensity at maize plants on a scale from 1 (plants not attacked) to 9 (plants complete destroyed), saved plants percent at 30 days from maize emergence and plants height at 50 days from plants emergence. At maize untreated plants, the weevils attack intensity was 3.16 in 2020 and 5.71 in 2021, while at variants treated with organic insecticide on a base of plant extracts from the Fabaceae family the weevils attack intensity ranged from 3.08 to 3.14 in 2020 and from 5.65 to 5.68 in 2021. The lowest value of the weevils attack intensity was registered in the case of the variant with seeds treated with imidacloprid active ingredient (I=2.56 in 2020; I=4.46 in 2021). The highest values of saved plants percent were registered in the case of the variant with seeds treated with imidacloprid (94.04 % in 2020, respectively 86.80 % in 2021). In this two-year study, in field conditions, in the southeast of Romania, it hasn’t registered significant statistical differences concerning weevils attack registered at untreated maize plants and maize variants treated with organic insecticide on a base of plant extracts from the Fabaceae family (0.3 %). Both years haven’t registered significant statistical differences concerning plant heights at 50 days from the maize emergence.