When do you reccomend applying Marathon for the most effective control the entire season? Is there a whitefly control schedule available as far as when to spray and when to apply Marathon?

Whitefly Management Program with an Emphasis on the Q-biotype is a document that outlines whitefly management at different stages of poinsettia production. You can see from the title of the document that emphasis of the program is on control of the Q Biotype whitefly however research in the last couple of years has shown that the B Biotype may be showing just as much resistance to many of the chemicals that the Q Biotype is thought to be resistant to. The take home message here is that resistance management is very important with whitefly control period, regardless of which biotype you are dealing with. Rotation of chemicals is key to resistance management and that will mean relying on other chemicals in your rotation besides just Marathon and other chemicals in the neonicotinoid class.

Please review the document and let us know if you have further questions. Thanks!

Is Aug. 31 to early to apply marathon?

Over the years I have learned two things about Marathon Granules...
(1) Do not count on Marathon alone to be the end all product if you apply it to a crop of Poinsettias already infected with 2-3 generations of whitefly. There will be some resistance and you will be un-happy later on in the crop cycle when the whitefly population explodes. Do all of your chemical rotations now and use sprays to kill off the whitefly before a Marathon application. Think of Marathon as a good insurance policy on an already clean crop.
(2) Don't apply Marathon so early in the crop cycle that its effectivness wears out when the crop is in color. I always apply in very late September or the first of October down here on the Texas Gulf Coast. Any sooner and the Marathon is long gone by the first of December in my case. Your mileage may vary!....Michael Pawelek

Michael, have you ever seen leaf burn associated with applications of Marathon granules and high temperatures? I got into the habit of applying later to avoid leaf edge burn and rolling on some of the older foliage.
And you are right about Marathon not working miracles -- it worked great one year and didn't do squat the next! Gotta rotate!

Deanne, No I have not encountered any leaf edge burn with the Marathon granules but I am very careful that the granules are spread out over the whole soil surface at the first watering and that they do not congregate in a pile at one place. My first two waterings after application are just enough to spread out the granules without hardly any water dripping out the bottom of the containers. If much liquid comes out the bottom I see dollar bills dropping to the floor! ....Michael

You know, I haven't used Marathon for 4 years now. 5 or 6 years ago I bought an Auquafog atomizer from Jaybird Manufacturing. If I spray every 10 days, rotate chemical MOAs after two aps, I have zero whitefly...and mite, aphids, thrips in the spring. I quit using Marathon because every year we put it on it was always so hot, then I would have to spoon feed water for a week to keep from dropping it out the bottom of the pot. This atomizer, similar idea to Dramm's Cold Fogger but much cheaper, has allowed me to put away my hydraulic sprayer and also quit applying Marathon. In those 5-6 years, I have had less than 6 outbreaks where I have had to actually get a sprayer out. You can spray a 3,000 square foot house in 10 minutes, or in my larger ranges I set it off and go home. It has a timer to shut it down when it's finished. The largest area I spray at a time is a 1/2 acre, I think that is the max according to the manufacturer. Worth looking at if you are like me and sick of Marathon not working.

Greenthumb....do you mind me asking what chemicals you use in your rotation and when you start? thanks!

Meridith:

I usually start right after transplant. I spray every 10 days. I spray the chemical twice (2 sprayings 10 days apart), then rotate to another mode of action. This year I started with Avid/Azatin. Now I have moved to Judo and Schmitar. After I spray that twice I will rotate again.

This is off the top of my head, not in the office. Here are the chemicals I run through my mist blower for whitefly...

Avid/Azatin
Judo/Schimitar
Enstar or Distance
Endevor
Marathon II or Tristar

I will also run Decree through it the end of November, great for any risk of botrytis.

I never run hort oil through it, that won't work. Also run miticides and thrip/aphid pesticides through it in the spring. I swear by it, sure saves time.