Q: Is spring really the best time to attempt crabgrass control?
--S.Y., Lennox A: Many experts believe that if you wait beyond spring, any crabgrass seeds in the soil will sprout, making chances of control slim.
Control usually is a sure thing if you use a pre-emergent crabgrass killer before the seeds emerge from the soil. According to lawn experts, such as O. M. Scott & Son, by the time crabgrass starts growing, a pre-emergent herbicide won't help. A spring pre-emergent application of balan or a herbicide in combination with a fertilizer for a spring feeding, will not damage the desirable turf grass. The incorporated herbicide will kill weeds as well as crabgrass. If the spring "treatment window" is missed, the herbicide Betasan can be used for control.
Q: We have lost one avocado tree after another because our soil is infected with avocado root-rot fungus. Should we give up?--K.M., Fullerton A: University of California researchers have concluded that they can successfully replant avocados in known root- rot areas by using a mound-planting technique. By placing trees on soil mounds, drainage and soil aeration are improved. Avocados now are being grown commercially in areas where the disease has killed thousands of acres of trees because of the cultural technique.
Drip irrigation and the dimensions of the planting mound are important. University of California researchers used mounds about 18 inches high and 3 feet in diameter at the original soil level. They also recommend that the mounds be compacted or well-settled.