Big Bud Disease in Tomatoes and Peppers

This fact sheet provides information on the symptoms of big bud on tomatoes and peppers. It reviews the disease cycle and recommendations on controlling beet leafhopper and managing big bud disease in Utah

Importance of seed as an inoculum source for High Plains Virus in sweet corn

High Plains Virus (HPV) is found in small grains and corn and is commonly transmitted by the wheat curl mite. In 2016, a local farmer had a high incidence of HPV in all of his sweet corn in three different locations. However no mites were found. Drone imagery was taken of the field and showed a pattern of infected corn plants that indicated that the virus was seed borne. Yield loss was an estimated 50% for the field. Seed transmission of HPV in corn has been considered unimportant in the past due to low percentage of infection (Forster et al. 2001). The objective of this project was to determine the level of seed contamination with HPV and rate of seed transmission to corn plants

Fire Blight of Pears and Apples

This fact sheet describes fire blight, a bacterial disease of concern to apple and pear growers, and how it can be managed

Desynchronization of pulse-coupled oscillators with delayed excitatory coupling

Collective behavior of pulse-coupled oscillators has been investigated widely. As an example of pulse-coupled networks, fireflies display many kinds of flashing patterns. Mirollo and Strogatz (1990) proposed a pulse-coupled oscillator model to explain the synchronization of South East Asian fireflies ({\itshape Pteroptyx malaccae}). However, transmission delays were not considered in their model. In fact, the presence of transmission delays can lead to desychronization. In this paper, pulse-coupled oscillator networks with delayed excitatory coupling are studied. Our main result is that under reasonable assumptions, pulse-coupled oscillator networks with delayed excitatory coupling can not achieve complete synchronization, which can explain why another species of fireflies ({\itshape Photinus pyralis}) rarely synchronizes flashing. Finally, two numerical simulations are given. In the first simulation, we illustrate that even if all the initial phases are very close to each other, there could still be big variations in the times to process the pulses in the pipeline. It implies that asymptotical synchronization typically also cannot be achieved. In the second simulation, we exhibit a phenomenon of clustering synchronization

Powdery Mildews on Vegetables

Powdery mildew is one of the most easily recognized fungal plant diseases. It is categorized by spots or patches of white-to-gray powder-like growth on foliage, stems, or fruit. Roughly 700 species exist that infect grasses, ornamentals, weeds, fruit trees, landscape trees, shrubs, and vegetables. The closely related species of fungi that cause powdery mildew are host-specific, meaning they cannot survive without the proper host. Powdery mildew fungi spread in conditions of low rainfall and hot temperatures, making Utah’s climate the perfect environment. This fact sheet provides information on powdery mildew and its management