What is the disease on my apple tree?
I have a few questions: I’m suspecting some kind of fungal infection in all my plants both vegetables and perennial plants.. It has greatly affected their growth and flowering. Some have died off completely. The 1st picture is of lavender. I tried 2 rounds of lavender in s sunny well drained garden bed. They dried out even with regular watering. Coreopsis that is nest the lavenders also looks dried out but managing somehow! The 2nd picture is of catmint. Is it powdery mildew? Last picture is the leaf from my apple tree. All my three apple trees have the same brown spots on the leaves. They were also attacked by Japanese beetles heavily in the preceding years although we had some control this year. However, the growth is stunted. Please see the pictures attached and advise. Location is Owings mills. Thank you very much!
Baltimore County Maryland
Hi- as you know, lavender needs a dry, sunny site and grows poorly in soils high in clay and organic matter. We cannot diagnose the specific cause(s) of the decline you observed. The root zone may have had more water and less air than needed. It's also possible that the roots were infected with one of the fungal pathogens that are encouraged by moist soil conditions. Southern blight would be another possibility: https://extension.umd.edu/hgic/topics/southern-blight
We suggest you avoid using wood mulches around lavender in the future.
The white spots on the catmint are not powdery mildew. They are small feeding spots (stipples) caused by one or more small, sucking insect pests (leafhoppers, aphids, planthoppers). They are considered minor pests and the leaves can be used for culinary purposes.
The apple leaf shows symptoms consistent with various fungal leaf spots. Apple has a large number of insect, mite, and disease pests in Maryland. We suggest you rake up and dispose of all fallen leaves to reduce the amount of disease inoculum available to infect the trees next spring. Pruning to improve air circulation through the canopy is also useful. Spraying with fungicides can also be very helpful in managing diseases. Please read the VA Tech home fruit spray information on apple: