The lilacs have finished blooming so if you need to prune them, this is the time to get that done. Remember to cut them back far enough to give them room to grow to the size you will want them to be. If there are no leaves on the stems when you have finished the task, that’s OK. They will develop new leaves on the stems that have been cut back.
I noticed black spots showing up on Goldsrum Rudbeckia (common name is black-eyed susan). That is evidence of septora leaf spot, a fungus that will destroy the beauty of the plant in a matter of days with the heat and humidity common for us.
This fungus is easily controlled with a spray application of Daconil. Thorough leave coverage is necessary, meaning both top and bottom of the leaf. An application now will stop the infection but will not make the existing black spots go away. The fungicide prevents the disease from spreading. Often, if caught early enough, new growth will cover up the diseased leaves to make the damage less visible.
And then another insect pest that has appeared in mass is psyllid. This is a sap-sucking insect and one of its favorite “juice bars” is purple dome aster.
This year the stress of drought coupled by the voracious feeding of these insects is doing serious damage to the aster foliage with the potential of actually killing the plant.
Eight is a Bonide brand insecticide that does an excellent job of eradicating these pests. Again, application to all leaf surfaces for thorough coverage and one spray is normally all you need for the season.
Eight insecticide and Daconil fungicide are two valuable tools to have in your arsenal for pest control. Both are broad spectrum and are safe to use.
That being said, I try not to use them on blooming plants when bees are present because they can be toxic to our pollinator friends. So that means if the plants are blooming, you need to spray early, like really early in the morning before the bees become active. Generally, we hope the spray has dried before the bees start working.
An application of Daconil to tomato plants now will give a head start to preventing blights later in the season. The plants might not be blooming yet, so protecting the bees isn’t an issue. Also, remember that preventing a disease is much easier that trying to cure it when the symptoms appear.