The Cooperative Extension Service is a national network of land-grant colleges, universities, and the United States Department of Agriculture serving communities across the country by providing research-based information and educational programming. Purdue Extension serves Indiana residents in the following program areas: Agriculture and Natural Resources, Health and Human Sciences, Community Development, and 4-H Youth Development. Purdue Extension offices are located in all 92 Indiana counties! One of Purdue Extension’s signature programs is the Purdue Master Gardener Program. The purpose of the Purdue Master Gardener Program is to train volunteers to assist Purdue Extension Offices with consumer horticulture education needs in local communities. Purdue Master Gardeners complete horticultural training in a variety of topics from plant and soil science to fruit, vegetable, and ornamental gardening. The Purdue Master Gardener Basic Training is conducted by Purdue Extension Educators in participating Indiana Counties. To become a Purdue Master Gardener Intern, participants must complete the[Read More…]
Archives for June 2019
Viburnum leaf beetle, a newly arrived exotic pest in Indiana may be the cause of viburnum defoliation. Report this pest to 1-866-NO-EXOTIC if you find this insect in Indiana.
Although most cities contain an Elm Street, very few cities can claim having mature American elms on that street, or any other. The American elm was a premier street tree: Tolerant of compacted soil, fast growing, long-lived, and with a beautiful vase-shaped form. It’s very popularity led to its downfall. The introduction of Dutch elm disease (DED) in the 1900’s began devastating the elm population, which fell like dominos due to its overabundance in the urban and forest landscape. Although no number will be determined, the loss of hundreds of millions of elms is considered a conservative estimate, at best. The elm host. Native Elm species vary in their susceptibility to DED. American elm (Ulmus americana L.) is highly susceptible, cedar elm (U. crassifolia Nutt.), rock elm (U. thomasii Sarg.), September elm (U. serotina Sarg.), slippery elm (U. rubra Muhl.), and winged elm (U. alata Michx.), range from susceptible to[Read More…]
Like anthracnose diseases of other shade trees, sycamore anthracnose is a very common occurrence in the landscape (Figure 1). Symptoms of sycamore anthracnose normally develop as small spots or dead areas centered along the veins of leaves or along leaf margins (Figure 2). Under conducive conditions these spots expand, killing more leaf tissue and causing premature leaf drop. However, damage can be pretty severe in prolonged wet, cool weather like we have been experiencing (Figure 3). Extensive twig or shoot blight occurs when young, growing shoots are killed, leaving affected stems leafless until dormant buds farther down, below the dead tissue, are able to develop and push out new leaves (Figure 4). This type of damage causes the tree limbs to look deformed or gnarled due to the repeated infections and twig death caused by this disease (Figure 5). It is commonly observed that the very top of the tree[Read More…]
Introduction The Colorado Blue spruce is not native to Indiana and tends to be susceptible to disease. One common disease, caused by the fungus Rizosphaera kalkhoffii, results in the defoliation of the tree. If left untreated needlecast can lead to the death of the tree. Symptoms and Signs Symptoms of needlecast don’t develop until two to three years after initial infection. Needles will turn a purplish brown color and fall from the tree. As needles fall the branches of the tree will start to die. The disease typically starts in lower portions of the tree where humidity and temperatures are higher. However, it is not uncommon to see disease develop in patches higher in the tree. Disease Cycle Rhizosphaera overwinters in the needles then sporulates in the spring when temperatures become warm and humidity rises. The spores, called pycnidia, form rows of black dots along the length of the needle[Read More…]
It takes more than a tiny leaf mining weevil to kill a vigorously growing elm tree.