Curly top

[2] Knowledge of curly top's early history in the United States is limited owing to its sharing similar symptoms with other diseases and disorders.

[9] According to C. O. Townsend, George G. Hedgecock with the USDA reported that, on several occasions before 1888, he observed damaging outbreaks of a disease presumed to be curly top from garden beets in Nebraska.

In 1897, George Austin stated that the Utah Sugar Company suffered overwhelming losses near Lehi, UT from an unidentified disorder resembling curly top.

However, he did not attribute the appearance of the disease to any viral or pathogenic entity, figuring that the damage was directly caused by the feeding injury induced by the insect.

Nucleotide sequence comparisons suggest that curtoviruses and begomoviruses diverged after a recombination event altered insect vector specificity (Rybicki 1994).

Before the development of commercialized agriculture in the western United States, the native flora did not support large, economically damaging populations of the beet leafhopper.

This series of factors resulted in the disappearance of previously stable plant populations that were replaced by various winter and summer annual weed species.

In the fall as crops senesce, the leafhopper vector moves to breeding areas in the foothills away from cultivated fields, overwintering on various biennials and perennials.

[12] The most common infected hosts include sugar beets (for which the disease was first named), follow by tomatoes,[13] peppers, beans, potatoes, spinach, cucurbits, cabbage, alfalfa, and many ornamentals.

Although crop failures are rare today, curly top is still a potentially problematic issue for sugar beet production in several areas of the western United States.

This one disease was responsible for the closure of numerous processing plants across this growing region, in a similar manner to the impact of the cyst nematode on the European continent in the latter half of the 19th century.

Its damage also directly contributed to wild fluctuations in sugar prices due to varying supply and demand relationships, causing the cultivation of beets to constantly move to new locations, leaving others abandoned.

Following this year, the entire company very nearly closed and declared bankruptcy as a direct result of curly top, after only 7500 acres were harvested and processed.