Question From: Metamora, Illinois, United States
Q: I have whitefly in the greenhouse on some peppers and tomatoes. I have some pyrethrin spray to use, but it says on the label not to spray when plants are in flower. What is the reason for this? My plants ARE in flower, so will it do any harm to the plants and/or US when we eat the produce if I do spray the plants? I have already sprayed them once.
Wendy, I am not trained in the use of insecticides, especially for use in a greenhouse. However, I do know that pyrethrin carries the signal word CAUTION and is used on edibles. While I can't say for sure I think the reference not to use while plants are in flower has to do with killing pollinators. However both tomatoes and peppers are self pollinating so that would not be an issue. However, peppers and tomatoes grown in a greenhouse should be shaken several times during the hours of 10 and 2 to move the pollen around. A broom handle swept over the tops of the peppers will do the job. Growers use special machines. For more information on the insecticide contact the manufacturer. Best And Happy Yardening, Nancy