Abstract Sunflowers are attacked by insect pests at various stages of crop development. Among them there is a complex of species of Coleoptera order, genus Listroderes Schoenherr, commonly known as “sunflower weevils”. The adults affect the crop at the early stages of its development. During 2019-2020 growing season, adult of Listroderes foveatus (Lea) species caused significant losses in the sunflower plant stand, in several sunflower plots of the southeastern region of Buenos Aires province. Damage at basal level of the plant stem was registered. Depending on the vegetative development stage, they caused their cut or strangulation, followed by overturning and subsequent death. The magnitude of the damage caused was reflected in the need for total or partial resowing in several sunflower plots.

Resumen El cultivo de girasol es afectado por insectos plaga en sus diferentes estadios de desarrollo vegetativo. Entre estos, se encuentra un complejo de coleópteros del género Listroderes Schoenherr, conocidos vulgarmente como “gorgojos del girasol”. Los adultos afectan al cultivo en las primeras etapas de su desarrollo. Durante el ciclo agrícola 2019-2020, adultos de la especie Listroderes foveatus (Lea) causaron pérdidas significativas en la densidad de plantas logradas de girasol, en varios lotes de la región del sudeste de la provincia de Buenos Aires. Se registró daños a nivel de la base del tallo de las plantas. Dependiendo de su estadio de desarrollo vegetativo, ocasionaron su corte o estrangulamiento, seguido por vuelco y posterior muerte. La magnitud de los daños producidos se reflejó en la necesidad de resiembra parcial o total en varios lotes de girasol.

Abstract The genus Copitarsia Hampson (Lepidoptera. Noctuidae) includes agricultural pests of at least 48 crop plants and they are distributed from Mexico to southern South America. In South America, from Venezuela to Chile and Argentina, Copitarsia incommoda (Walker) is one of the most economic important species of the genus. In this work, we record for the first time for Copitarsia, and specifically for C. incommoda, larvae feeding on soybean leaves and beans. Also, this species is recorded for the first time for Argentina, feeding on lucerne crops. Finally, we provide a larval identification key for most common noctuoids soybean pests of South America, including C. incommoda. This will be helpful for identify this species in soybean crops without the need of larvae rearing.

The grey field slug Deroceras reticulatum has become a pest in no tillage sunflower (Helianthus annuus L.) and soybean (Glycine max L.) crops in the southeast of Buenos Aires province, Argentina. Ground beetles (Coleoptera: Carabidae) are an important component of the arthropod community in agricultural systems and have the potential to reduce pest populations. We tested the predation capacity of the carabid beetle Scarites anthracinus on Deroceras reticulatum individuals of different body mass (10, 20 and 30 mg) and on their eggs, in a controlled laboratory no-choice assay. We also tested its preference for juvenile slugs and the similarly-sized pillbugs (Armadillidium vulgare), under choice conditions. This beetle preyed upon both eggs and juvenile slugs, with the highest consumption rate on 20 mg body mass individuals. While preferring the pillbug during the first 24 h of the choice test, our results suggest that in field conditions, S. anthracinus might be a natural enemy of D. reticulatum, consuming slug eggs and juveniles of different body mass.

La babosa gris grande Deroceras reticulatum se ha convertido en una plaga importante de los cultivos de girasol (Helianthus annuus L.) y soja (Glycine max L.) en siembra directa del sudeste de la provincia de Buenos Aires, Argentina. Por su parte, los carábidos (Coleoptera: Carabidae), son importantes componentes de la comunidad de artrópodos en los agroecosistemas y tienen el potencial para reducir las poblaciones de invertebrados. Determinamos la predación de Scarites anthracinus sobre huevos y juveniles de diferente masa corporal (10, 20 and 30 mg) de D. reticulatum, en experimentos de no elección en condiciones controladas de laboratorio, y la preferencia alimentaria por juveniles de babosas y bichos bolita Armadillidium vulgare de tamaño similar, en experimentos de elección. S. anthracinus consumió huevos y juveniles de babosas con una tasa de consumo mayor de individuos de 20 mg. A pesar de una mayor preferencia por bichos bolita durante las primeras 24 h del ensayo, los resultados sugieren que S. anthracinus podría actuar como enemigo natural de D. reticulatum en condiciones de campo, consumiendo huevos y juveniles de diferente masa corporal.