to delay picking until all the bolls were ready for picking because the quality of the cotton deteriorated as soon as bolls opened. But about the time mechanical pickers were introduced, plant breeders developed hybrid cotton varieties with bolls higher off the ground and that ripened uniformly. With those innovations, the harvester could make just one pass through the field. Also, herbicides were developed to defoliate the plants and drop their leaves before the picker came through, producing a cleaner harvest. Conventional harvester The first harvesters were only capable of harvesting one row of cotton at a time, but were still able to replace up to forty hand laborers. The current cotton picker is a self-propelled machine that removes cotton lint and seed (seed-cotton) from the plant at up to six rows at a time. There are two types of pickers in use today. One is the "stripper" picker, primarily found in use in Texas. They are also found in Arkansas. It removes not only the lint from the plant, but a fair deal of the plant matter as well (such as unopened bolls). Later, the plant matter is separated from the lint through a process dropping heavier matter before the lint makes it to the basket at the rear of the picker. The other type of picker is the "spindle" picker. It uses rows of barbed spindles that rotate at high speed and remove the seed-cotton from the plant. The seed-cotton is then removed from the spindles by a counter-rotating doffer and is then blown up into the basket. Once the basket is full the picker dumps the seed-cotton into a "module builder". The module builder creates a compact "brick" of seed-cotton, weighing approximately 21,000 lb (16 un-ginned bales), which can be stored in the field or in the "gin yard" until it is ginned. Each ginned bale weighs roughly 480 lb (218.2 kg). An industry-exclusive on-board round module builder was offered by John Deere in 2007. In c.2008 the Case IH Module Express 625 was designed in collaboration with ginners and growers to provide a cotton picker with the ability to build modules while harvesting the crop. References Holley, Donald. Mechanical Cotton Picker Encyclopedia article, University of Arkansas at Monticello International Harvester article from Engineering & Technology for a Sustainable World "Recent Progress in the Mechanization of Cotton Production in the United States," by Gilbert C. Fite ©