What is the meaning of the quote "Lottery in June, corn be heavy soon"?

Old Man Warner, the oldest man in town, repeats this old saying in Shirley Jackson's "The Lottery" as a way to express his disdain for other communities that have decided to give up the lottery as a community tradition.
The saying, "Lottery in June, corn be heavy soon" is meant to sound like an aphorism, or an old saying that goes back so far in time, it can't be argued, altered, or ignored. The inclusion of the lottery in an aphorism makes the existence of the lottery as normal and commonplace and inevitable as a June rainstorm or a July harvest of corn.
The fact that Old Man Warner is the speaker of the saying indicates that the tradition of the lottery goes back generations and generations; if he, the oldest man in town, repeats a saying of this old style, the tradition behind it must go back even further than the reader might have expected at the start of the story.