Rusts are mostly damaged to dash crops
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Answer:
There are three different rust diseases that affect wheat—leaf rust (also known as brown rust or orange rust), stripe rust (commonly known as yellow rust), and stem rust (commonly referred to as black rust of black stem rust). Of these, leaf rust is the most frequently occurring in Ohio, but in any given year, any of these diseases can infect and cause substantial yield losses if not adequately managed. Rusts are notorious for their ability to spread rapidly and reduce wheat yield and quality. It all depends on the susceptibility of the variety, race of the pathogen present, timing of infection, and the weather conditions. Damage to wheat depends on the growth stage at the time of infection and the overall level of rust severity. High levels of disease before or during flowering usually have the greatest impact on yield. Rust causes losses by reducing the number of kernels per head and the size of the kernels, and by lowering test weight and the protein content of the grain. In the case of stem rust, additional losses may result from girdling of the stems which cause plants to lodge. However, for years, the widespread use of rust-resistant varieties has substantially reduced losses caused by leaf, stripe and stem rust. In addition, since none of the rust fungi typically overwinter in Ohio and other parts of the Midwest, spores have to be blown up from the south in order for these diseases to develop, and in most years, this usually occur very late in the season, towards the end of grain development. Some leaf rust can be found on volunteer plants in the fall, but these fall infections appear to be of limited importance for the occurrence and spread of the disease in the spring. In Ohio, late May and early June are times when rust infection becomes critical and rust is more damaging on late-maturing varieties in years when cool, moist weather persists into mid-summer, extending the growing season.