1) Mites 
Harvest mites. These are small orange-red mites that cause intense itching, particularly on the feet, at harvest time.
<dermatology> A skin infestation, common in the southern United States, caused by the larva of the red mite (harvest mite). Features include an itchy red rash to the waist, ankle and skin folds. No specific treatment is necessary as the rash will resolve spontaneously. Antihistamines can be used to control itching. ... (05 Jan 1998) ... 
Harvest mite - mites within the Family Trombiculidae. The larvae of these mites, called Chiggers, are parasitic and can cause considerable irritation and swelling.
Common name for Trombiculidiasis.