August 13, 2021

Juglone – What is it?


Juglone is a chemical that inhibits the growth of certain plant species.  When plants produce a chemical that prevents the growth of other plants, it is called allelopathy.

Controlling Weeds in the Home Vegetable Garden


Control of weeds in the vegetable garden is important. These unwanted plants are strong competitors for available water, nutrients, and sunlight and can reduce yields when not controlled.

Oak Wilt or Bot Twig Canker?


A year after the derecho, we lost so many beautiful trees while others lost limbs. We always remind oak lovers to avoid unnecessary pruning from April to July to minimize the risk of Oak wilt transmission. We had questions at the Plant and Insect Diagnostic Clinic from oak caretakers wondering if their derecho injured trees may be infected with oak wilt after the derecho.

Summer Foliar Lilac Diseases

Top: spots of various sizes, random distribution can coalesce and blight the leaf Middle: the arrow show fungal structures Bottom: magnification showing Pseudocercospora spores

​With summer comes lilac leaf spots; at the plant clinic this year, we have seen the usual fungal pathogen Pseudocercospora causing leaf spots and blight (rapid death). Historically, Septoria leaf spot and powdery mildew also contribute to leaf blight, and in some cases, to abundant leaf drop.  Environmental conditions, humidity, and stressors like drought, shaded locations, or lack of proper pruning could be exacerbating these problems.

Emerald Ash Borer Discovered in 3 More Iowa Counties


Emerald ash borer has been found in Calhoun, Winnebago and Worth counties for the first time. 

I See Dead Plants Podcast


A new integrated pest management podcast from Iowa State University Extension and Outreach is now open to listeners interested in learning how plant science research impacts everyday life.