Google Scholar is an ok tool for research but you'll get better results in less time if you learn how use advanced databases (like those linked on this page). They're not that hard to use and as long as the database is a good match for your topic, you should get better results.
This page contains links to scholarly databases and resources that will help you locate materials related to plant pathology. If you are not sure where to start, try a general database before moving on to more specialized databases.
Research tip: Always search in multiple databases.
Each database is different - they differ in interface, coverage, and features and there's no database that covers everything. This is why you will need to use more than one.
Use a general purpose database when you're not sure where to start, which terms to use, or if you are researching an interdisciplinary topic.