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Resistant whitefly

Discussion in 'Florida Lawn Care Forum' started by jvanvliet, Dec 3, 2011.

  1. jvanvliet

    jvanvliet LawnSite Gold Member
    Messages: 3,944

    The Ficus continues to be heavily infested with active white fly, normaly they'll have gone dormant or have succumbed to the colder weather by now.

    They don't seem to be responding as well to imidacloprid, bifertin, Aloft, or Orthene. Squirt guys here have been treating them with the same stuff (mostly Imidacloprid) for years instead of cycling the pesticide. Treatment has usually been limited to a foliar drench; very few guys will throw down a granular.

    We were just retained to treat hedges for whitefly... After a discussion with Helena chemical, I learned guys were not having as much success with the usual low cost products, which accounts for the continued activity.

    I'd like to hear about whitefly activity around the state (specially the Gumbo Limbo) and the chemical experience treating it. We just completed a foliar spray using Safari on 1,800 ft. of hedge. I'll check Monday for efficacy.
  2. phasthound

    phasthound LawnSite Fanatic
    Messages: 5,149

    The overuse of pesticide is the cause of pesticide resistance, as you have correctly pointed out. We have learned that even the rotation of different classes of pesticides may still build up resistance. If you are successful with your recent application, additional cultural management practices will provide better results.
    If you are concerned about long term control and making a client happy, please consider the following information taken from http://miami-dade.ifas.ufl.edu/pdfs/urban_hort/The Fig Whitefly (AUG2008) Fact Sheet.pdf

    Management: Although efforts to understand and control this pest are ongoing, there are several potential options for whitefly control. However, it is necessary to consider the site (landscape, hedge, large tree, container, production, etc), the size and number of trees, and the surrounding environment before taking steps to control this pest. For large trees, for example, a foliar spray may not be possible.

    In the landscape, several natural enemies have been observed attacking this whitefly which can play an important role in long term control. Awareness of these natural enemies is very important so decisions for additional control measures can be made wisely so as not to also kill the natural enemies. The most commonly seen natural enemies include beetle predators, parasitoids, and lacewings.

    Monitor your ficus plants for early signs of an infestation because it will be easier to manage the pest before it builds to high populations and causes major damage. Defoliation usually occurs after the whiteflies have been there for several generations. Also, if infested trees or hedges are trimmed, either leave the clippings on the property or if removing, bag the clippings to reduce the chance of spreading the insects. If clippings are being transported in a truck, be sure to either bag them or cover these clippings with a tarp. Although the eggs and early stages of the whitefly on fallen leaves will die, the last nymphal stage of the whitefly can likely survive, emerge into an adult and attack more ficus. Insecticidal soap or oil sprays may be an effective method of control for small trees or shrubs, but, thorough coverage of the undersides of the leaves is especially important. It will also be necessary to repeat these applications every 7 to 10 days. The use of other insecticides may be necessary to control this pest. However, it is important to use products that will not be detrimental to the natural enemies. Protecting natural enemies may be a critical component in the long-term control of this pest. Insecticides with systemic properties may be very useful in whitefly control because they can be applied as a drench to the soil and provide longer lasting control.
  3. jvanvliet

    jvanvliet LawnSite Gold Member
    Messages: 3,944

    Thank you. We covered this in the white fly seminar the Palm Beach extension hosted recently. Cultural practices are great, but not always practical. Chemical application is always a last resort.
  4. greendoctor

    greendoctor LawnSite Fanatic
    Messages: 10,003

    Question. Is this whitefly not susceptible to IGR type materials? Reason why I ask is because in my state, it is safe for me to assume that any species of whitefly and mealybug are at least partially resistant to neonicotinoids and pyrethroid insecticides. That leaves oil, Orthene, and IGRs. What drives this resistance is lack of rotation(everyone with a bottle of Talstar or pack of Merit 75 WP is a pest management pro) and poor coverage due to incorrect/inadequate equipment(same "expert" is applying to high trees and dense shrubbery with nothing more than a manual backpack sprayer). Upon review of the Florida bulletin, Endeavor, Distance, Talus and Judo/Forbid, are products not neonicotinoids or pyrethroids and allowed in landscapes. Endosulfan would be terrific for this but last I heard, that will be banned in 2014 and has not been legal in landscapes for at least 20 years.

    My usual program for whitefly begins with Orthene, followed by an IGR and ends with a soil injection of Merit. I say soil injection because it is rare that I am treating plants on porous soils that will take a drench acceptably.
  5. Plantculture

    Plantculture LawnSite Member
    Messages: 128

    The problem in our situation (SE FL) is that there are neighborhoods and towns with ficus trees all over and 1000's upon 1000's of feet of ficus hedges up to 20' tall. Their life cycle is very fast in the middle of summer, so treating your hedges with an igr will certainly help, but they will fly in from other properties. That would mean treating at a shorter interval than every 3 months which is pretty common around here, but may be necessary in the future.
    I have been using an imidacloprid drench with good success. I don't like the idea of spraying the hedges all the time because you kill a beneficial insect that feeds on ficus thrips.
    I think down the road you will see ficus hedges only in the neighborhoods where people will fork over the dough to manage them.
  6. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    My county lists all plants in the Genus of Ficus as noxious exotics. They are in Fact Illegal to plant in my county. We do have a few older Banyan Trees but the Popular Ficus benjamina or weeping Fig so popular in your area is illegal here.

    The Main Reason for our county making them illegal is their invasive root system. I am always so surprised to see the Light Years of Ficus hedge all over the East coast as Privacy barriers. I often wonder why you all don't have big plumbing problems.

    Also I am reading you only treat ornamental plants every 90 days. I tried that and went back to every 60 days for better control. I think we have more open wet lands in my area than your area. Nocturnal Flying Chewing Insects are a problem that must be addressed with repellent insecticides Because these are travelling Pests. Repellents don't last very long in our rainy season.
  7. jvanvliet

    jvanvliet LawnSite Gold Member
    Messages: 3,944

    Interesting that your county has banned them, good idea. I've always recommended cocoplum for hedge plantings as opposed to ficus. I encourage HO's and HOA's to switch the capital they invest on whitefly treatment into removing and replacing the ficus with a resistant hedge planting. People love the ficus because they grow fast and are cheap, although with the required treatments they are high cost maintenance.
  8. jvanvliet

    jvanvliet LawnSite Gold Member
    Messages: 3,944

    A foliar orthene spray (or bifertin) followed by a Imidacloprid root injection very early in the spring has proved to be efficacious for six - eight months bringing us into the cold season. Unfortunately our warm season (zone 9/10) is dragging on into December and the fly is endemic. We will treat topically for control until the temperatures abate.

    I'm sure IGR's are effective. Like plantculture said, ficus is everywhere from hedges to trees. Not everybody treats so while a IGR would be effective on the existing larvae & pupae on a given plant, it would only be re-infested in short order from neighboring ficus thus demanding more spraying which would result in the eradication of beneficial insects.

    Next year the game plan is a foliar spray & to inject Dinetefuran, Clothianadin and Imidacloprid in rotation and only as necesary for control. I'm hoping FL will aprove thiamethoxam for lawn and garden use soon; I know these are all neonicotinoids.

    Another genus of white fly is moving up the peninsula, gumbo limbo white fly. Unlike the fig, which is apparently finicky, the gumbo limbo is not and has a voracious appetite. Last I heard (end of October) it was as far north as Hollywood Florida. It's this fly I'm hoping to hear some field experience about.
  9. greendoctor

    greendoctor LawnSite Fanatic
    Messages: 10,003

    Understood. What also drives resistance is usage of neonicotinoids as foliar treatments. Reason for that is sublethal application techniques and product rates. I would not be in business for long if I only applied foliar sprays or only soil injections. A foliar spray does not last long enough and a soil treatment takes a very long time to go up. Especially with the erratic weather here. It is either cold and rainy, causing plants to shut down and not uptake materials or it is hot and dry.
  10. greendoctor

    greendoctor LawnSite Fanatic
    Messages: 10,003

    To add, I am very careful about clothianidin and dinotefuran because they do not last. Properly applied imidacloprid lasts for up to 12 months if not longer in my area.

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