- Author: Neil McRoberts
Risk to spring lettuce from TSWV is generally low in the San Joaquin Valley because virus incidence is reduced by the winter period and lettuce cropping is generally finished by the time the levels of virus start to build up again in late spring and early summer. All that being said, occasional and serious attacks can occur, particularly when thrips numbers are high early in the season. In that situation thrips feeding damage can be a problem in its own right, independent of whether there is a high level of TSWV. For more detailed advice on management of thrips refer to the UC IPM guide, which can be found by clicking on this text.
This year we're off to a generally warm start, which means thrips numbers will probably build up relatively quickly. The first generation post-winter is at peak adult numbers right now. The peak of egg hatch for the next generation will be early in the first week of April, with adult numbers peaking again about three weeks later (around April 24th).