For a variety of reasons I have resisted “sounding the alarm” for potential whitefly problems in 2017. We have been seeing more whiteflies than usual throughout the winter months, but we have also been looking closer than usual. However, today I saw a sample from a melon field that had as severe an infestation as I have ever seen in August, and we are still in May. Given this severe whitefly sighting, we have the potential to generate even worse populations than we had last year, especially if we have a dry summer. The one saving grace is that we have not yet seen significant occurrences of viruses in the system (knock on wood).
Simply put, we went into winter with ridiculous populations and we have undoubtedly overwintered higher than normal populations, particularly where we have acreages of favorable winter hosts like cole crops. The large acreage of cabbage and collards (and now kale) is probably why our “normal” whitefly problems are located where they are located. The really bad population in melons was on the same farm where they had been battling whitefly in kale all winter.
From this point forward I can only suggest keeping a very close eye on all host crops (for example vegetables, cotton, peanuts, beans, etc.) and treating before the population gets too entrenched. The vast majority of insecticides we use for control of whiteflies are efficacious against immature stages and cause relatively minimal mortality of adults; thus, it is nearly impossible to regain control once the population reaches outbreak proportions. Finally, when you are done with any host crop, destroy the remains of that crop as soon as possible, particularly if there are any whiteflies in the field. Anything we do now to reduce populations will reduce the potential for problems in cotton and other summer hosts which produce the populations that enter vegetables in the fall.