July 1, 1994
Black flies (buffalo gnats) are once again starting to make their presence felt across the state. While we always seem to have some black flies every year, the last two years have seen higher than normal populations.
A problem encountered by some home gardeners in recent weeks is the sudden wilting of tomato plants. The two most likely causes of wilting are vascular wilts and stalk borers.
The initial symptoms of Verticillium and Fusarium wilts are wilting of the plant leaves during the heat of the day. Affected plants often recover in the evening or overnight. Gradually, however, the wilting becomes progressively worse and many plants eventually die.
A prominent plant in many Iowa lawns in early summer is white clover. White clover (Trifolium repens) is a creeping perennial. Plant stems root at the nodes where they touch the soil. The leaves are composed of 3 leaflets. Plants bloom profusely in early summer. Flower heads consist of 20 to 40 individual white to pinkish-white, fragrant flowers. White clover is common in many lawns because it is a prolific seed producer and adapts well to mowing and other lawn care practices.
Imagine a horror movie depicting a plant species that grows everywhere, consuming cars, buildings, and everything in its path. Although this is strictly science fiction, there are plants that are quite aggressive, taking over a garden, forest, or turfgrass areas in a short period of time. An example of this is the kudzu vine (Pueraria lobata). It was widely grown in the southeast United States as a fodder plant, to control erosion, and sometimes as an ornamental. Due to its rapid growth rate it has become a rampant weed. Fortunately, kudzu is not hardy in Iowa.
The common stalk borer is a slender, purple and white striped caterpillar that can be found tunneling inside the stems of a wide variety of plants. It is most commonly found inside the stalk of giant ragweed, but is of some importance as a pest of potatoes, tomatoes, corn and other plants. Samples and calls indicate the abundance of this pest is much greater than average this year.
It is often difficult to estimate when vegetable crops will be ready to be harvested. Weather conditions effect growth and development of the crop and can advance or delay maturity. For flowering vegetables, days from flowering provides a fairly accurate determination of harvest time.
Days from Flowering to Maturity
Crop Time (Days)