Farmers use various pesticides to control pests, weeds, and diseases in order to meet the demands in terms of yields and quality of agricultural products. The use of pesticides in Uruguay has increased steadily since 2000(1). The total number and amount of active substances imported increased from 3.9 to 10.6 thousand tons between years 2000 and 2020. Within plant protection products, herbicides had the highest increase, from 2.1 thousand tons in 2000 to 9.5 thousand tons in 2020(1). Similar trends are observed worldwide(2).

Most plant pathogens exhibit host specificity but when former barriers to infection break down, new diseases can rapidly emerge. For a number of fungal diseases, there is increasing evidence that hybridization plays a major role in driving host jumps. However, the relative contributions of existing variation versus new mutations in adapting to new host(s) is unclear. Here we reconstruct the evolutionary history of two recently emerged populations of the fungus Pyricularia oryzae that are responsible for two new plant diseases:wheat blast and grey leaf spot of ryegrasses.

Herramienta para la clasificación de ambientes basada en el índice verde.

Herramienta para la clasificación de ambientes basada en el índice verde.

ABSTRACT.- Plants deploy diverse anti-herbivore defences which reduce feeding and performance of herbivores. Temperate grasses use silicon (Si) accumulation and Epichloë-endophytes for physical and chemical (i.e. endophytic-alkaloids) defence against insect herbivores. Recent studies suggest that Epichloë-endophytes increase Si accumulation in their host grass. It is unknown, however, how this affects Si-deposition on the leaf surface, their impacts on insect herbivore feeding efficiency and their immunity to potential infection/parasitism.