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This work was carried out with the objective of documenting the main biostimulants used in the world to mitigate the effects of water stress, as well as the physiological, morphological and biochemical effect that these substances cause in the crops that have been studied. A review of scientific articles published in national and international journals, as well as master's and doctoral theses from different universities and scientific centers was carried out. The application of biostimulants is one of the most promising agricultural practices to mitigate the effects of drought on plants. There are numerous microorganisms in the world, as well as synthetic or naturally occurring substances that have a positive effect on crop development, yields and drought tolerance. They can optimize biochemical, physiological and anatomical processes such as regulating stomatal conductance, increasing the concentration of proline and cellular osmolytes, increasing photosynthetic efficiency, inducing the production of LEA proteins and antioxidant enzymes, reducing cell membrane damage, maintaining leaf water content and increasing the soil exploration capacity of the root system. [ABSTRACT FROM AUTHOR]

This research was done in Fomento municipality, Sancti Spíritus, in Cuba, from 2011 through 2013 in two ecosystems and in two sowing times (rainy and dry seasons). The objectives were to describe the life cycle of Peregrinus maidis (Ashmead) and the damage caused to corn (Zea mays L.), to identify the main pest bio-regulators naturally occurring in two agro-ecosystems, and to determine the predator-prey relationship. The experiment was arranged in a randomized block design. The data were collected through observation at weekly intervals. In order to estimate the number of pest insects and bio-regulators occurring on the plants, 25 plants per parcel were selected for a total of 100 plants per treatment (maize/squash, maize/beans, maize/ Sesame, maize/sunflower, and maize monoculture). Once the research was accomplished, it was concluded that P maidis had been present since the first week, and reached its population peak in week six. The lower indexes of affectation occurred in the pre-mountain agro-ecosystems, and with more frequency in the maize/sesame and maize/squash polyculture, which depended on the time of the year and the season. Fifteen species of P. maidis control insects of were identified, and Scymnus sp was found in all treatments. The life cycle of P maidis averaged 5.4 days more in the dry season than in rain season. The predator-prey relationship showed relatively superior indexes in the polyculture systems than in monocrops systems. [ABSTRACT FROM AUTHOR]