Influence of plastic covering on raspberry infection by Thekopsora americana.

• Grant number: 22/14848-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2023
• End date: December 31, 2023
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Daiana Maria Queiroz Azevedo
• Grantee: Gabriel Wildner Cordeschi Leite
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 19/13191-5 - Epidemiological components, damage characterization and control of tropical and temperate rusts at a global climate change scenario, AP.TEM

Abstract

Raspberries are traditionally grown in cold climate, particularly in North America andEastern Europe. Due to the increasing global demand for this fruit, its cultivation is expandingto non-traditional regions, including subtropical regions of Brazil. Cultivating raspberries innon-traditional climate is possible partly because of the use of plastic coverings byproducers, which minimize climatic variations and mitigate the effects of radiation andexcessive temperatures on the fruits. Light restriction established by plastic coverings caninduce changes in the morpho-anatomy of the leaves, such as leaf area increase,parenchyma thickness reduction and modifications in stomatal density. Late rust caused byThekopsora americana is the most important foliar disease of raspberry, causing up to 100%damage, and it is the most frequent on crop in Brazil. The influence on morpho-anatomicalchanges on infections by foliar pathogens are poorly understood and more studies arenecessary. The aim of this research is to evaluate the effect of plastic covering on T.americana infection and on the morpho-anatomy of healthy and T. americana-inoculatedraspberry leaves. Part of the research will be carried out in a commercial raspberry orchardwith the cultivar 'Heritage, located in Piracicaba-SP. Raspberry plants covered with plastic anuncovered will be inoculated with T. americana urediniospores in leaves on their basal,middle and apical thirds. Samples from covered and uncovered plants, healthy andinoculated, will be collected, fixed in Karnovsky's solution and processed for analysis ofstomatal density and studies of T. americana infection under a scanning electronmicroscope. Another part of the research will be carried out in the experimental field ofESALQ. Potted plants kept in a greenhouse under plastic cover and uncovered will beinoculated with T. americana to the evaluation of the monocyclic components. Ourhypothesis is that plastic covering alters the morphology of the raspberry leaf blade, withconsequences on the infection of the pathogen.