We have struggled with whiteflies this year and we still have a few really bad spots. These plants have a lot of sooty mold and a few plants even appear as though the pests are literally sucking the life out of them. I had treated with Flagship in late Sept./early Oct. and Marathon in early Nov. We've been fogging like crazy and even tried a few wet sprays. All of these applications have provided some degree of knockdown, but I think we just got too far behind and there are so many nymph/larval stages on the leaves still. I'm sure we'll have to trash some of them, but for the others and for the protection of surrounding uninfested plants I have two questions: Is there anything we can do about the sooty mold? Can I spray Tristar in these hotspots or would that be too many Class 4 applications?
Thanks,
Erin

What about a Pyrethroid? check the labels, but maybe "Judo"??? Just a thought.

Erin, there are a lot of folks that have been there and know that feeling. In a perfect situation you would not apply Tristar. However, that may be the best step in this situation. Use the highest label rate and it is important to get as much coverage as possible down in the plant canopy. The last nymph stage does not feed and will not be killed. Adults will continue to emerge for a week or so and then will be killed when they start feeding. Use sticky cards set out for about 4 hours each day. In a couple of days the number of adults on the cards should start going down. Marathon is probably not the best product for use in November. It is less mobile in the plant and less moves into the lower leaves. Marathon is probably better applied 2-3 weeks after pinch when all of the leaves are actively growing. For Nov. Tristar or Safari are probably the better options in this class of chemicals. Good luck. Jim

Hi Erin - Dr. Barrett has you headed in the right direction, so we just have a couple of additional comments. For hotspots we also like a tank mix of Talstar/Avid which you could apply 3-4 days before the Safari or Tristar of 3-4 days after to catch the adults that are hatching.

Lower leaf removal is also something to think about because there is probably a heavy population of eggs especially on the lower leaves. If the sooty mold is that bad they'll have to be removed anyway and it’s a good way to knock out a good percentage of the population even before your chemical application.

If you don't want to remove the leaves and you want to try and clean the sooty mold you can try a Capsil solution - mix 1 oz. of Capsil in 1 gallon. Spray the foliage and rinse immediately with clear water. The solution may help clean the leaves and remove some of the sooty mold.

Good Luck!

Hi Erin--we also had a rough time with whitely this year- especially in November as the canopy was closing in. I had to spend extra time "wet" spraying and making sure that I had really good coverage under the leaves before I got a good knockdown. I had the best luck with a tank mix of Azitin and Safari. (We are a fairly large place, so Flagship was a little too expensive for hand spraying large areas.) I don't usually like to tank mix, but I was desparate. Early in the season prior to first color I also had luck with Judo.

Hi Erin,

little late but maybe usefull. I had a resonable Whitefly population in october. That's when i applied my Marathon drench. Wish i could have done that end op september but due to nutrient issues i had that to take care of first.
In november i waited long enough for Marathon. I ran a test and 55% of the Whitefly was Q-biotype and resistant to Marathon. 2 days after Marathon, Avid + Taltstar. 8 days late Sanmite. Tristar 10 days later and Talstar 3 days later. Had a lot of adult kill, not suficient enough. I guess i should have kept my interval shorter? But my result is loaded with Whitefly at start shipping Nov 28. My last option was a Safari drench at high rates, 5 days later no more whitefly, or viable eggs, nymphs or Larvea. Wish i would have done this in October, since it works for 6 to 7 weeks.

For those who have consistant whitefly problems I would recommend adding an Insect Growth Regulator (IGR) to your tank mix such as "Distance IGR". Killing just the adults never works very well as there will always be eggs and nympths present that many chemicals do not kill so days or weeks after an insecticide application the problem can pop up all over again. The IGR's keep the eggs and nympths from growing into the next stage of development so they never end up as adults on your plants. I believe that "Distance IGR" is translaminar in its action so spraying it on the top of the leaves in effect eventually transports the chemical to the bottom surface also. Someone correct me on this point if I am incorrect!.....Michael Pawelek

I have found that Safari does a great job on whitflies for us for 2 years now. I don't apply it until early October and it gives me total control through shipping. Before the Safari application I will control in August and Sept by rotating sprays of chemicals like Avid and Talstar.