Farmers are spraying for other pests, but at the same time selecting for pyrethroid resistance in lygus in alfalfa, and the bugs are carrying the resistance with them to cotton. More than 80 percent of lygus populations tested in 1998-99 were resistant to pyrethroids. Pyrethroids were the most effective group of pesticides for lygus control in the 1990s and we don't have new selective pesticides to replace them. In contrast, pesticide resistance in spider mites is manageable because it declines each winter. In the early season, resistance is less than 5 percent, but then swells to about 30 percent in the late summer.
Aphid resistance is high, however, natural enemies can help farmers keep the pest under control.
Wet spring weather would help researchers study grapevine disease Last year's dry, cold spring practically eliminated the incidence of phomopsis disease in grapevines. That was good news for growers, but scientists were sent back to the drawing board when each of their experimental treatments to combat phomopsis turned out statistically identical to the untreated control. University of California Cooperative Extension viticulture farm advisor George Leavitt is one researcher studying new treatments for phomopsis. In the spring, around the time of bud break, the fungus' fruit body produces spores that ooze onto the surface forming gelatinous curlicues on the vine surface. When it rains, the spores are splashed around and infect the young shoots.