CNNMoney So far this month, it's been more Shocktober than Rocktober for stocks. TheDow,S&P 500andNasdaqplunged again Tuesday and are down about 2% during the first few trading days of October -- despite thebig rally Fridayfollowing thejobs report. Will stocks continue to slide for the rest of the month? October is notorious for some of the worst market crashes in history. Whether or not we get another one will all depend on corporate earnings. KFC and Taco Bell ownerYum! Brands(YUM)kicked off things Tuesday after the closing bell. It's the first major company to report results for the third quarter. Earnings and sales missed forecasts. Costco(COST),Monsanto(MON)andAlcoa(AA)are due to release their earnings on Wednesday.Pepsi(PEP)will report earnings on Thursday. Corporate America needs to deliver strong results to make investors forget about Ebola, ISIS and signs of economic weakness in Europe and China. Analysts had originally expected earnings growth of 9% for the third quarter back in August, according to FactSet. It may be tough to justify why stocks should head that much higher from current levels given that the estimated earnings growth rate for the quarter has been nearly cut in half. One expert thinks companies also have to show that their profits are going up because of revenue growth -- higher demand for their products and services. It's not enough to just have cost cutting from mergers and layoffs as well as stock buybacks boosting earnings through lower share counts. Sales are expected to increase in the quarter. But the 3.6% growth rate is lower than the growth rate for earnings. "We are at the stage of the recovery where organic earnings matter. Financial engineering, not so much," wrote Tom Stringfellow, president and chief investment officer of Frost Investment Advisors in a report Tuesday.