Stick with the best varieties for dry or wet years. Yes, there is a certain danger from irrigating while there is no leaf canopy during the summer. Scald in alfalfa is caused when standing water covers the soil and direct bright sunlight heats the soil and water. After a few inches of regrowth foliage shades the soil and plants are normallyunharmed by standing water during bright sun. Plants growing without shaded soil suffered from scald.
Most scalded plants die during a few days or weeks.
If you have sprinkle irrigation move the sprinkle line quickly enough the first time around so that water does not stand for more than an hour. Then, the other irrigations can allow water to stand because plants will shade the soil from direct sunlight. It seems like we get more grasshoppers during dry weather. Early summer is the time to control grasshoppers. Producers should not wait until they are winged and large, when control is difficult or impossible.