What steps should greenhouse growers take to build a successful whitefly management program? SAF weighs in with these suggestions:
1. Scout weekly! Use sticky cards to monitor adults, and check the undersides of leaves to monitor the immature population. Visual inspections, sticky cards and product performance-scouting are all necessary. Don’t let the whiteflies get ahead of you, or your treatment options will be more limited. Don’t wait until shipment to find out you have whiteflies!
2. Do not rely on just one or two effective products. Rotate, rotate and rotate some more with different modes of action to decrease the potential for developing resistance. A resistant B-biotype can be just as bad as a Q-biotype! Or, if you are using a product that only kills the B-biotypes and have a mixed population, you will end up with more Q-biotypes, which are harder to control.
Growers should also time product applications to meet label recommendations for the current life stage present. If neonicotinoids are applied too early in the crop cycle and/or heavy irrigation has occurred, the active ingredient residual may not last or may be leached out before the end of the crop cycle.
3. Contact your propagator, your local extension agent or university expert if you have problems. Knowing which biotype you are dealing with will help you choose the most effective control products: Q-biotype and some B-biotype whiteflies are resistant to certain products and will not be effectively controlled unless you use the correct program. Get your whiteflies biotyped. The biotyping process is fast, free, and information will be kept absolutely confidential. The Whitefly Management Program provides the contact address to which samples may be sent for biotyping.
4. Practice good sanitation between crop cycles. Whitefly management does not end once you ship. It is very important not to develop a resistant whitefly population develop within your greenhouse. Then, cycle it from crop to crop! Make every effort to eradicate residual populations after shipment. It’s important for your vegetable, cotton, or peanut-producing neighbors – and it’s important for your future crop years. Letting whiteflies – and especially difficult-to-manage populations of either biotype – survive within your greenhouse is just a headache, and maybe a disaster, waiting to happen.
5. Inspect incoming shipments and isolate if necessary. Zero-tolerance is not the goal for anyone, so you may see a whitefly or two when your shipments arrive. That’s normal and means that your propagator or rooting station is probably following good management practices. But if you see many whiteflies on incoming shipments, keep those plants separate from your other crops until they have been treated. And inform your propagator or rooting station.
6. Watch your neighbors’ fields. If you’re near cotton, peanut or vegetable fields (and especially if you are in a part of the country that has been hot and dry over the summer), you may see whiteflies migrate to your greenhouse at the end of their season. Obviously, you don’t want to be contributing whiteflies to their fields, either!
Want more information on whitefly control? Take advice from Kansas State University’s Ray Cloyd in this FloriCAST episode with scouting, cultural management, pest control and parasitoid advice on whiteflies.