If Warrior or Baythroid is used, a spray interval of 3 to 4 days should provide adequate control. Cool temperatures favor adequate control at the longer end of these spray intervals. Populations of crabgrass are greatest in the southern parts of the state. Large crabgrass usually has gray-green sometimes green foliage and dense coarse hair. Crabgrass plants are generally low growing.
Crabgrasses are summer annuals that germinate and grow best late in the season.
The optimum soil temperatures for germination are 85 to 95 o F. Crabgrass persists in the soil as seed. A single large crabgrass plant can produce 150,000 seeds. During the growing season crabgrass plants tiller, resulting in lateral development of a large infestation from a single seedling plant. Crabgrass is native to Eurasia and was introduced by the United States Patent Office in 1849 as a forage. Immigrants during the late 1800's also introduced crabgrass as a grain.