It would be best to place weeds that are producing seeds and diseased plant debris in biodegradable bags and have the material picked up and composed by a municipal or commercial composting facility. The temperatures in home compost piles…
Temperatures of 150 to 180 degrees Fahrenheit are required to kill most plant disease pathogens. Unfortunately, the internal temperatures of most home compost piles don’t reach this level and the disease organisms are not destroyed. For many home…
Phytophthora root rot can be a serious problem in poorly drained sites. Phytophthora root rot can be avoided by planting blueberries in well-drained soils. Outside of root rots, blueberries generally have few insect and disease…
Foliar diseases of tomatoes are a common problem in the home garden. Fungal diseases, such as early blight (Alternaria tomatophila and Alternaria solani), late blight (Phytophthora infestans), and…
Proper cleaning and sanitization of pruners and other garden tools is important to prevent the spread of disease issues. At minimum when removing disease-infected plant material, pruners should be disinfected between plants. Ideally,…
The symptoms are those of peach leaf curl. Peach leaf curl is a fungal disease. The disease is caused by the fungus Taphrina deformans. Infections occur as the peach tree buds begin to swell in spring.
The ‘Spring Snow’ crabapple is widely planted as it’s one of the few crabapple varieties that doesn’t bear fruit. Unfortunately, ‘Spring Snow’ is very susceptible to apple scab.
The leaf drop is probably due to anthracnose. Anthracnose is a common fungal disease of trees in Iowa. Anthracnose may occur on ash, sycamore, maple, oak, walnut, and other deciduous trees (see encyclopedia article…
The sap oozing from the elm wound is probably due to bacterial wetwood or slime flux. Bacterial wetwood or slime flux is a common on elm, cottonwood, and mulberry. It also occurs on maple, birch, ash…
Fire blight is probably responsible for the wilted shoots on your crabapple. Fire blight is caused by the bacterium Erwinia amylovora. Plants susceptible to fire blight include apple, crabapple, pear, hawthorn, and…
The gray, velvety growth on your berries may be gray mold. It is also known as Botrytis fruit rot. Gray mold is favored by poor air circulation and a high humidity in the strawberry planting. The most commonly infected berries…
The symptoms on your bee balms (Monarda spp.) are most likely due to powdery mildew. Powdery mildew is a common fungal disease on bee balms. Symptoms are most severe on overcrowded plants and those growing in partial shade.…
Cherry leaf spot is probably responsible for the symptoms on your cherry tree. Cherry leaf spot is caused by the fungus Blumeriella jaapii. The fungus produces small purple spots on the upper surface of the leaves. …
The black sooty material is likely sooty mold. Sooty mold is caused by several different fungi. The fungi don’t infect plants, but grow on the sugary honeydew excreted by aphids, scales, mealybugs, and other insects. In…
The spotting and premature leaf drop on your dogwoods is probably due to Septoria leaf spot. Septoria leaf spot is a common fungal disease of dogwoods in Iowa. The disease typically causes irregularly shaped grayish spots with dark…
In Iowa, the foliage of the river birch (Betula nigra) often turns a sickly yellow-green. The yellow-green foliage is due to a deficiency of iron. The problem is referred to as iron chlorosis. (A close examination of chlorotic leaves…
Oedema is probably responsible for the lesions on the undersides of the ivy geranium leaves. Oedema is not caused by an insect or disease pathogen. It is a physiological problem. Oedema is most often encountered in greenhouses…
The large, hard growth is probably crown gall. Crown gall is caused by the bacterium Agrobacterium tumefaciens. The bacterial disease can infect roses, grapes, apples, raspberries, willows, euonymus, and many other woody…
Ash rust is probably responsible for the orange growths on your ash tree. Ash rust is caused by the fungus Puccinia sparganioides. The fungus produces conspicuous swellings on leaves, petioles, and twigs. Infected…
Symptoms of impatiens downy mildew initially appear as yellowing of infected leaves. The yellow-green foliage may initially be confused with a nutritional deficiency. As the infection progresses, leaves may curl downward and a white, fuzzy growth…
Brown rot is a common fungal disease of peaches and other stone fruits. Affected fruits develop circular light brown spots that expand rapidly and rot the fruit. Sometimes the fungus that causes this rot is visible as ash-gray tufts.…
The main objective in spraying apple trees is to prevent insect damage to the fruit. The most important period to spray apple trees is from petal drop until just prior to harvest. Several applications will need to be made during this…
All varieties of the common garden impatiens (Impatiens walleriana) and interspecific hybrids with an Impatiens walleriana parent (such as Fusion and Butterfly impatiens) are susceptible to Impatiens downy mildew. Garden balsam…
Snow molds may be responsible for the brown spots in your lawn. Two snow mold diseases, gray snow mold and pink snow mold, occur in Iowa. Gray snow mold is caused by two species of the fungus Typhula, while pink snow mold is…
The leaf drop is likely due to anthracnose. Anthracnose is a common fungal disease of sycamore, ash, maple, oak, and other trees. Anthracnose is most severe in years with cool, wet spring weather. While anthracnose may cause extensive defoliation…
