From a disease transmission standpoint, My guess is that most are talking about CWD. As a deer hunter (both gun and bow) for over 30 years I have opinions on hunting methods and things hunters do to give themselves an advantage. I will also say that I do not bait or use food plots. As a member of Wisconsin's CWD Stakeholder advisory board, I have met the researchers and sat through their study presentations and read and heard their data on CWD transmission and the risks. From a disease transmission standpoint, any method of attracting, congregating and feeding deer has a certain risk level. This includes all ways that hunters attract, congregate and feed deer whether it is grown or poured out. Most are unaware that CWD is more easily transferred from the environment than it is from host to host. In fact once in the soil, CWD prions become 700% more infective that CWD prions transferred from an infected host animal to another. What makes it worse is that those prions bind to the soil and remain infective for over a decade. (one study proved at least 16 years). This is what lead CWD guru Judd Aiken to make this statement last week in the Science News From the New York Times
"Dr. Aiken said prions tended to bind to clay in soil and to persist indefinitely. When deer graze on infected dirt, prions that are tightly bound to clay will persist for long periods in their intestinal regions. SO THERE IS NO CHANCE CHRONIC WASTING DISEASE WILL BE ERADICATED, he said. Outside the laboratory, nothing can inactivate prions bound to soil. They are also impervious to radiation. "
Hunters growing turnips and beets and clovers and all the other food plot varieties, are contributing to the spread of CWD just the same as a hunter dumping corn. We also know that deer that frequent hunter provided food will urinate and defecate in that area so repeatedly attracting deer to piles or food plots will over time build up an environmental reservoir of infected prions in the soil. Since food plots do not move each year this is a constant location for prion shedding. Baits move from year to year and are only temporary but neither is immune from the negative effects of disease transmission. It is the fecal and urine based transmission into the soil that is getting the most attention because it outweighs the amount of saliva that is deposited by deer by many times. Here is more from the article.
" Researchers are reporting that they have solved a longstanding mystery about the rapid spread of a fatal brain infection in deer, elk and moose in the Midwest and West. The infectious agent, which leads to chronic wasting disease, is spread in the feces of infected animals long before they become ill, according to a study published online Wednesday by the journal Nature. The agent is retained in the soil, where it, along with plants, is eaten by other animals, which then become infected.
The finding explains the extremely high rates of transmission among deer, said the study's lead author, Dr. Stanley B. Prusiner, director of the Institute for Neurodegenerative Diseases at the University of California, San Francisco.
First identified in deer in Colorado in 1967, the disease is now found throughout 14 states and 2 Canadian provinces. It leads to emaciation, staggering and death.
Unlike other animals, Dr. Prusiner said, deer give off the infectious agent, a form of protein called a prion, from lymph tissue in their intestinal linings up to a year before they develop the disease. By contrast, cattle that develop a related disease, mad cow, do not easily shed prions into the environment but accumulate them in their brains and spinal tissues.
There is no evidence to date that humans who hunt, kill and eat deer have developed chronic wasting disease. Nor does the prion that causes it pass naturally to other animal species in the wild. Besides mad cow and chronic wasting disease, the prion diseases include Creutzfeldt-Jakob, which leads to dementia and death in humans. Each of these diseases is caused by a different strain, and all strains behave somewhat differently. In the case of chronic wasting disease, "it turns out prions exploit the oldest trick in the book used by pathogens and parasites," said Mike Miller, a veterinarian at the Colorado Division of Wildlife who is an expert on chronic wasting disease.
"Fecal-oral transmission is very effective," Dr. Miller continued. Each deer excretes about two pounds of fecal pellets a day. As wild herds move around, or captive herds are trucked between states, more soil becomes infected. In captive herds, up to 90 percent of animals develop the disease, Dr. Prusiner said. In wild herds, a third of animals can be infected. "This is an important finding," said Judd M. Aiken, a leading prion expert who is director of the Alberta Veterinary Research Institute in Canada and who was not involved in the new study. "Most of us suspected that prions might be spread in feces, but we needed proof."
"The fact that prions are shed at a preclinical stage of the disease is very significant," Dr. Aiken added.
The study was carried out in two parts. First, Dr. Miller and his team infected five mule deer by feeding them brain tissue from an infected animal. They took fecal samples before infection and at three to six months afterward. The deer came down with chronic wasting disease 16 to 20 months later.
Four to nine months after infection, the deer began shedding prions in low levels in their feces, even though they had no symptoms. Surprisingly, an infected deer could shed as many prions at this stage as would accumulate in its brain during terminal disease. In the second part of the experiment, Erdem Tamguney, an assistant professor at Dr. Prusiner's institute, created a strain of mice with deerlike prions in their brains.
When Dr. Tamguney inoculated the brains of these mice with feces from infected but asymptomatic deer, half developed symptoms of chronic wasting disease. Fourteen out of 15 fecal samples transmitted the disease to some of the mice. Dr. Aiken said prions tended to bind to clay in soil and to persist indefinitely. When deer graze on infected dirt, prions that are tightly bound to clay will persist for long periods in their intestinal regions. So there is no chance chronic wasting disease will be eradicated, he said. Outside the laboratory, nothing can inactivate prions bound to soil. They are also impervious to radiation."
From a disease transmission standpoint, there is little difference between food plots and corn or apple piles except that the piles are used for a much shorter time period and move around from year to year. If you're concerned about CWD and you are a food plotter, you should change your methods to reduce the risk. If you're in favor of plots but opposed to piles, you're off base and a bit of a hypocrite. From an ethical standpoint, if you are using hunter provided food to attract, congregate and feed deer to advantage your hunting situation, it does not matter if you grow it or pour it. you placed it there as a hunter to give you an advantage in seeing and taking game and once you hunt over or near it, you are a baiter. Just like a recurve and compound hunter are both bowhunters, food plotters and corn pilers are both baiters just using different means to reach the same goal.