While marigolds are seldom bothered by insects and diseases, they are not problem free. Spider mites can devastate marigolds in hot, dry weather. Grasshoppers can also cause considerable damage. Aster yellows is an occasional…
Borax has sometimes been touted to kill creeping Charlie (Glechoma hederacea) in lawns. Borax contains boron, an essential plant micronutrient. However, the difference between plant requirements and toxicity problems is very small. When…
The black spots are probably sooty blotch or flyspeck. Sooty blotch and flyspeck are two different fungal diseases that often occur together on apples. Sooty blotch appears as dark brown to black, ½ inch or larger smudges on the…
Whether a crop is safe to eat after accidental exposure to a herbicide depends on several factors, including the type of herbicide used, its active ingredient(s), concentration, mode of action, and other relevant considerations. The…
Pouring boiling water on weeds can be used for control, especially in situations where other plants are not nearby, such as in cracks in patios or sidewalks. Boiling water will act as a contact "herbicide", killing only the portion of…
Russeting is probably responsible for the tan-colored spots on your pears. Russeting also develops on the surface of apples. While affected fruit are not attractive, russeting doesn’t affect the eating quality of the fruit.
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…
Ash trees infected with emerald ash borer (EAB) do not need to be treated or chipped when removed. If you do plan to keep the wood for campfires or fireplaces use it on your property and do not transport the wood to new locations. Any…
Symptoms of herbicide damage vary and depend on the type, formulation, concentration, mode of action, source, and amount of herbicide, as well as the plant species affected, application method, equipment used, and weather conditions during and…
The striped cucumber beetle is a common pest of cucurbit crops in the Midwest. The spotted cucumber beetle, also known as the southern corn rootworm, is also a pest of cucurbit crops, but the striped cucumber beetle has more economic impact due…
Perennial grassy weeds die back to ground level in fall but send up new growth in spring. These weed species have long, narrow leaves with parallel veins. They are often in the Poaceae (grass) family or a closely related family and…
Control of wild parsnip (Pastinaca sativa) and poison hemlock (Conium maculatum) is the same. Safely removing these weeds from the landscape is important as both species can be toxic to humans and animals.
Tall fescue is a cool-season perennial grass occasionally present in Iowa lawns. Because it has good drought, heat, and foot-traffic tolerance, the narrow-leaf varieties (sometimes called turf-type) can be a welcome addition to the…
Weedy vines are fast growing plants, getting very large in a relatively short amount of time often climbing and covering other garden plants. If left to grow, they can smother other plants blocking out light and killing the desirable plant.
Woody weeds are trees and shrubs that have woody plant tissue. They are perennial and typically classified as eudicots, although some may belong to other plant groups like gymnosperms (conifers). Examples of woody weeds include…
Mushrooms are the reproductive or fruiting structures of fungi. Their appearance in the lawn usually indicates decaying tree stumps or roots in the soil. In garden beds, mushrooms can appear because they are associated with decaying organic…
Annual weeds grow rapidly, flower, set seed and die in a single season. New annual weeds germinate from seeds each year. Before they die, most annual weeds produce large quantities of seeds.
Japanese beetles feed on many different types of plants. They can be problematic on sweet corn as they frequently feed on green corn silks, inhibiting pollination and leaving incomplete kernel filling in the ears. Silks must be clipped to less…
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,…
Crabgrass (Digitaria spp.) and quackgrass (Elymus repens) are two weedy grasses that stand out in traditional lawns as the leaves are much coarser than the Kentucky bluegrass, perennial ryegrass, and fescues that are typically…
The orange color is likely due to rust. Rust is a fungal disease. It can be diagnosed by walking across the lawn in white shoes. As you walk across the lawn, bright orange spores of the rust fungus will rub off onto the shoes,…
Bearded irises should be divided every three to five years. If not divided, plants become overcrowded and flower production decreases. July or August is the best time to dig, divide, and transplant bearded irises.
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,…
The curling of the tomato leaves may be a physiological disorder referred to as leaf roll. Affected leaves roll upward and inward. The leaves may also become thickened, giving the foliage a leathery appearance.
