Arthropods associated with medicinal plants in coastal South Carolina

AbstractArthropods were sampled from feverfew [Tanacetum parthenium (L.) Schultz‐Bip], Echinacea purpurea (L.) Moench, Echinacea pallida (Nutt.) Nutt., Valeriana officinalis L., and St. John's wort (Hypericum perforatum L.) during 1998‐2001. In addition, arthropods were sampled on tansy (Tanacetum vulgare L.) from 2001‐2004. In general, 50‐60 arthropod species where collected and identified among all of the medicinal plant species. Among the predators, Orius insidiosus (Say) (Hemiptera: Anthocoridae), Geocoris punctipes (Say) (Hemiptera: Lygaeidae) and spiders were most abundant from 1998‐2004. The three‐cornered alfalfa hopper, Spissistilus festinus (Say), was the most abundant herbivore found from 1998 to 2001. Orius insidiosus and G. punctipes were 3‐4 times more abundant on T. parthenium than on any other medicinal plant species. Based on the numbers of predatory arthropods found on T. parthenium, this crop could be suitable as a companion or “banker” plant to attract and maintain populations of predators, especially O. insidiosus and G. punctipes. Whitefly nymphs attacked by predators with piercing/sucking mouthparts are easily identified using a microscope because of the general appearance of the carcass left by the predators. Thus, populations of predators on T. parthenium suppressed Bemisia tabaci populations on E. purpurea when these crops were planted as companion crops.