ABSTRACT. The transgenic maize that expresses the Bt protein is one of the strategies most used for the control of Spodoptera frugiperda, key pests of this crop in America. With the objective of verifying the susceptibility of S. frugiperda; toxicity studies were conducted of the proteins Bt expressed in leaves of different events of maize released in Paraguay, 2B587hx™ (cry1F); VT triple PRO™ (Cry1A/Cry2Ab/Cry3Bb) and Formula TL™ (Cry1Ab). The rearing of S. frugiperda was conducted in the laboratory to obtain a uniform population under controlled conditions of temperature (25 ± 2°C), relative humidity (60 ± 10%) and photoperiod of 14:10 h (L:D). Mortality was evaluated and in the case of survivors; the weight and length of the pupae, the fertility of the females, the longevity of the adults, the viability of eggs, and the duration of the different stages and the total cycle. The supply of larvae neonates in the leaves of maize of the event VT triple PRO™ produced 100% mortality; however, in the larvae fed with leaves of the events 2B587hx™ and Formula TL™; the mortality was 58% and 56%, respectively. The survivors to these treatments had a longer life cycle, fertility and reduced fertility.

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The mite Mononychellus planki (McGregor) is reported for the first time in Paraguay, collected from the different soybean producing areas. KEYWORDS. Glycine max. Phytophagous mite. Sampling. RESUMEN. Se da a conocer el primer registro en el Paraguay del ácaro Mononychellus planki (McGregor) colectados de las diferentes zonas productoras del cultivo de la soja. PALABRAS CLAVE. Ácaro fitófago. Glycine max. Muestreo.

Paraguayan livestock production is based mainly on the use of natural and sown pastures as basic cattle feed. Several genera of harmful insects reported in forage grasses can cause damage to both yield and quality of forage. A review of the insect collection of the Plant Protection Area of the Faculty of Agrarian Sciences, National University of Asunción was carried out, in order to prepare a list of insects with incidence in grasses. Then random sampling of different species of Poaceae showing insect damage in open areas of paddocks grazed by cattle was carried out during 2014‒2017 in all Regions of Paraguay. Thirteen different genera and species of pastures were collected and 20 species of insects were identified in the following orders: Hymenoptera (Formicidae family: 5 species); Isoptera (Termitidae: 3 species); Hemiptera (Cercopidae: 6 species; Lygaeidae: 1 species); Lepidoptera (Noctuidae: 2 species); and Orthoptera (Acrididae: 3 species). The most common forms of damage observed in pastures were: leaf consumption (25%), leaf cutting (25%) and leaf yellowing-drying (35%).

Spodoptera cosmioides Walk (Lepidoptera: Noctuidae) is a polyphagous species, considered a secondary pest in soybean crop. The Intacta soybean (Bt soybean) event was released in Paraguay with Bt proteins which are supposed to be toxic for caterpillars. However, the effects of these proteins in the Spodoptera cosmioides biology still uncertainty. This study evaluated the biological activity of Bt soybean in S. cosmioides that were fed on Bt and non-Bt soybean leaves under laboratory conditions. The experiment was carried out at the Laboratory of Entomology; temperature 26±2 ºC; relative humidity: 60±10%; photoperiod: 14:00 h where 150 neonate larvae were used per treatment. The period and viability of each stage, the mortality of larval, number of eggs and neonate per couple, and the period of larvae to adult were the assessed variables. Higher mortality was observed in larvae fed with intact soybeans, but without statistical differences with non-Bt soybeans. For larval survival, period, number and total period, no statistical differences were verified. Higher percentage of fertility was observed in soybeans non-Bt but no statistical differences.