ABSTRACT.- The aim of this study was to determine if different mixtures and monocultures of cover crops (CC) reduce aerial dry matter, number and diversity of autumn-winter weeds. Two experiments with different CC species were implanted in the INTA Pergamino Agricultural Experimental Station (Pergamino, Buenos Aires, Argentina, 33° 51'S, 60° 34'W) in 2018 and 2019. The species used were:Avena sativa, Triticosecale and Vicia villosa. Mixtures and monocultures of CC were used, in different proportions and densities, and were compared with a chemical fallow.

ABSTRACT.- Cover crops constitute an interesting option for cultural weed control. Expansion of herbicide resistant weeds in Uruguay, has been associated with an increase use of pre-emergent herbicides for their control. Crops residues could decrease their effectiveness. The objective of these work was to evaluate the effect of Avena strigosa straw and moment and amount of rain, in Amaranthus spp. control effectiveness by flumioxazin and sulfentrazone. Two experiments were carried out for each herbicide in pots, in a greenhouse.

ABSTRACT.- Biological control is an alternative strategy to control Cacopsylla bidens. The aim of this study was to untanglethe trophic network involving C. bidens as prey. Molecular techniques along with predator activity surveys were employed to evaluate predation on psylla. Feeding on C. bidens was detected for five predators:Chrysoperla externa, Chrysopidae sp., Hemerobiidae sp., Harmonia axyridis and Cycloneda sanguinea. All these predators begin to feed earlier in the season, apart from C. externawhich fedds from the third psylla generation.

ABSTRACT.- Plutella xylostella (L.) is one of the main pests in Brassicaceae crops, although, information regarding its biology on alternative hosts is scarce, crucial for its mass rearing. We studied the development, biology, and population parameters of P. xylostella, fed with different Brassicaceae. In laboratory conditions, P. xylostella was reared from larva 1 to adult. Larvae were fed with B. napus (rapeseed), Brassica carinata (Ethiopian rape), Brassica oleracea var. capitata (cabbage), Rapistrum rugosum (turnipweed) and Raphanus raphanistrum (radish).

ABSTRACT.- Plutella xylostella (L.) is one of the main pests in Brassicaceae crops, although, information regarding its biology on alternative hosts is scarce, crucial for its mass rearing. We studied the development, biology, and population parameters of P. xylostella, fed with different Brassicaceae. In laboratory conditions, P. xylostella was reared from larva 1 to adult. Larvae were fed with B. napus (rapeseed), Brassica carinata (Ethiopian rape), Brassica oleracea var. capitata (cabbage), Rapistrum rugosum (turnipweed) and Raphanus raphanistrum (radish).

ABSTRACT.- Thorough and systematic surveys of host associations of Anastrepha fraterculus and Ceratitis capitata are lacking in Uruguay. Our aim was to establish the host status in field conditions and the pattern of use of different fruit species in agroecosystems and wild environments in Uruguay. Tephritid monitoring was conducted in citrus and deciduous fruit orchards using McPhail traps baited with four PBX® yeast/borax pellets. A survey of host fruits was conducted by collecting fruits in commercial and non-commercial orchards and wild vegetation. Ceratitis capitata and A.

ABSTRACT.- Thorough and systematic surveys of host associations of Anastrepha fraterculus and Ceratitis capitata are lacking in Uruguay. Our aim was to establish the host status in field conditions and the pattern of use of different fruit species in agroecosystems and wild environments in Uruguay. Tephritid monitoring was conducted in citrus and deciduous fruit orchards using McPhail traps baited with four PBX® yeast/borax pellets. A survey of host fruits was conducted by collecting fruits in commercial and non-commercial orchards and wild vegetation. Ceratitis capitata and A.

ABSTRACT.- The incidence of Colletotrichum latent infections during fruit development was evaluated in south-eastern and south-central agroclimatic regions of Uruguay, in Arbequina, Cortina and Picual cultivars. Colletotrichum latent infections were present at all stages of olive fruit development, with a substantially higher incidence in the south-eastern (60.5%) than the south-central region (1.2%). The south-eastern had substantially greater number of days with high relative humidity (>80%) and light rainfall (

ABSTRACT.- Bitter rot (BR), caused by Colletotrichum spp., is one of the most prevalent fungal diseases of apple worldwide. Some Colletotrichum spp. also causes Glomerella leaf spot (GLS), a disease restricted to a few regions worldwide. Recently, we reported the presence of C. siamense causing BR on low-chill apple cultivars in central Argentina. In further studies we detected the presence of apple leaf spot also associated to Colletotrichum spp.

ABSTRACT.- Pecan scab caused by Venturia effusa is the main crop disease affecting leaves and fruits, resulting in defoliation and yield and fruit quality losses. Recently, pecan groves expanded into Uruguay, Brazil and Argentina, where the temperate-humid climate is conducive for scab development. Chemical control is difficult given the height of adult trees which exceeds 20 m. Therefore, the strategy consists on selecting tolerant cultivars accompanied by cultural management aimed at providing a good ventilation and light interception.