Invasive weeds should be of great concern to any rancher or farmer. Invasive weeds can reduce crop yields and many are unpalatable or toxic to livestock. In pastures, invasive weeds can produce virtual monocultures, thereby limiting the variety of plants in the diets of livestock. Most livestock will not eat invasive plants, and will, therefore selectively feed on native plants providing for the growth and spread of invasive populations. Farmers should be concerned about invasive plants in fields also. Invasive plants can crowd out desirable vegetation, as well as consume fertilizer and water. It is very important to control invasive weeds in fencerows and ditches adjacent to fields and rangelands. Invasive weeds in places adjacent to fields can act as a seed source and allow the plants to re-infest fields much more quickly and easily.

Spotted knapweed was introduced into North America accidently in the 1890's. Since then, it has spread to virtually every state in the nation and has been disastrous to the rangelands of Idaho, Montana, Washington and Minnesota. Spotted knapweed is unpalatable to livestock and is only eaten when other plants are not available. Spotted knapweed also releases a chemical from its roots that inhibits germination and slows the growth of many native plants. Plants can produce thousands of seeds each year and once a seed bank is established, eradication can take several years.

Asian soybean rust was first detected in the United States in the winter of 2004. It is now present in Florida, Georgia, Alabama, Arkansas, Louisiana, Texas and Mississippi. Almost all commercially grown soybean cultivars are susceptible to this disease. Asian soybean rust is caused by Phakospora pachyrizi, an invasive fungus. The fungus causes tan to reddish brown lesions on the surface of leaves, petioles, cotyledons, stems and pods. The disease progresses rapidly and leads to smaller seed and reduced yields. The spores of this fungus can only survive in the presence of its host; hosts include soybean, vetch, lespedeza, kudzu, and many legumes.

Feral hogs can cause a wide variety of problems for farmers and ranchers in the South. Hogs are omnivores and will eat almost anything including crops and feed. Feral hogs have also been known to prey upon young livestock and other small animals. Hogs are wallowers and rooters. These activities can destroy livestock and game fences and banks of agricultural ditches and streams. Feral hogs have also been shown to spread brucellosis to humans and livestock. While symptoms of a mild case of brucellosis can resemble the flu, severe infections can affect the central nervous system and the lining of the heart. There is, currently, no brucellosis vaccine available for humans.

Africanized honey bees were first reported in the United States in southern Texas in 1990. Since that time they have spread to Florida, Oklahoma, Arkansas, Louisiana, New Mexico, Arizona, Nevada and California. Since introduction into the United States the bees have caused 16 human deaths. Deaths to livestock and animals are much more frequent and are not currently being reported. Africanized honey bees closely resemble European honey bees, since they are a hybrid between African bees and European honey bees, and cannot be distinguished except by microscopic measurements. However, Africanized honey bees are much more defensive than European honey bees. Many human deaths are because of inability to get away from the swarming bees. Animal deaths are usually due to being tied or penned. Bees nest in any enclosed area, such as barbeque grills, mailboxes or other containers. A person walking within 50 feet of a nest can trigger an attack, while things that produce vibrations, such as a tractor, lawn mower or power tools, can trigger an attack from 100 feet.