Which of the following actions should be taken first when determining how to fertilize turf in which the grass is proving unusually susceptible to diseases and pests? apply a high-nitrogen chemical fertilizer until grass shows signs of improvement

withhold fertilizer prior to testing soil for chemical balance

eliminate weeds prior to applying a 20-20-20 organic fertilizer

apply a top-dressing of organic compost to the mowed, dethatched, and aerated grass