Gloria S. McCutcheon

Incidence of Parasitoids and Parasitism of Bemisia tabaci (Homoptera: Aleyrodidae) in Numerous Crops

Abstract Understanding the relationship of parasitoids with their insect hosts and crop plants is needed to develop good management strategies for Bemisia tabaci (Gennadius), a whitefly pest. The abundance and establishment of parasitoids of B. tabaci B-biotype were tested with taxonomically diverse plants in the greenhouse (7 plant species) and in the field (16 plant species in Egypt). Greenhouse tests were conducted on plants free of whitefly nymphs to avoid this influence on parasitoid behavior, and field tests were conducted in crops with feral populations of B. tabaci. In the greenhouse, the parasitoid, Encarsia pergandiella Howard, was most abundant on Vigna unguiculata (L.) Walpers, followed by Gossypium hirsutum L. The propensity for this parasitoid to forage on the bottom leaf surface compared with the top surface varied among crops (45–90% were on the bottom leaf surface) and over time (≈50% were on the bottom leaf surface around sunrise, whereas ≈90% were on the bottom surface by mid-day). Inundative releases of laboratory-reared parasitoids, Eretmocerus mundus (Mercet), into field crops increased parasitization rates in all crops tested. Some crops (e.g., two Brassica species and V. unguiculata) were more conducive to parasitism of B. tabaci than other crops (e.g., Cucumis sativus L. and Lycopersicon esculentum Miller). Findings from this research may be useful in the enhancement and conservation of parasitoids of Bemisia.

Bemisia argentifolii (Homoptera: Aleyrodidae) Attacking Species of Medicinal Herbal Plants

Abstract Research was conducted on the production potential of selected medicinal herbal plant species as new crops suitable for cultivation in South Carolina. Whiteflies (Bemisia argentifolii Bellows & Perring) were found in an experimental production field infesting five perennial species of medicinal herbal plants [feverfew, Tanacetum parthenium (L.) Schultz-Bipontinus; St. John’s wort, Hypericum perforatum L.; purple coneflower, Echinacea pallida (Nuttall) Nuttall and E. purpurea (L.) Moench; and common valerian, Valeriana officinalis L.]. This article reports on whiteflies attacking and developing on these plant species. Density of whitefly nymphs was highest (mean = 2.3/cm2) on the second fully expanded leaf on the apical meristem of E. purpurea as compared with the same leaf position on the other plant species where average whitefly density ranged from 0.1 to 0.6 nymphs per square centimeter from late November 1998 through January 1999. Similarly, adult capture on sticky cards was high (mean = 123 whiteflies per card) in plots of E. purpurea compared with plots of the other four species (mean = 8 to 20 whiteflies per card per species), and adult counts were elevated in the highest (440 kg N/ha) of three fertility rates in E. purpurea. Moreover, laboratory tests agreed with the observation of a higher population of B. argentifolii on E. purpurea compared with the other four plant species. The whitefly completed development on all five plant species, and whitefly-associated parasitoids emerged from field-leaf samples of each plant species.

Revival of Herbalism and Its Roots in Medicine

ABSTRACT The proper use of phytomedicines in human health care may add a dimension currently lacking in the United States in the treatment of certain diseases and syndromes. Sales of botanicals have been rising for the past few years and are expected to increase 12% to 16% annually for the next few years. As agriculturists, we are developing production techniques using good management practices to grow and process these new crops. However, a fundamental understanding of the genesis of this “new” industry is needed to appreciate the historic use of herbs and significance in society.

Dilemma of regulating dietary supplements.

ABSTRACT The manufacturing of herbal preparations or dietary supplements, has become a multibillion dollar industry in the United States. Presently, dietary supplements are not considered drugs by the government, but are classified as food supplements. The Dietary Supplement Health and Education Act of 1994 (DSHEA) has defined dietary supplements as a product intended to supplement the diet that contains one or more of a vitamin, mineral, an herb or other botanical, an amino acid or a dietary substance to supplement the diet by increasing the total dietary intake, or concentrates, metabolites, constituents, extracts or combinations of any ingredients described above. The main limitation of DSHEA is that it deals only with herbs as dietary supplements, i.e., as foods and not as drugs. A quandary still exists among: (1) the consumers who want to use these products safely; (2) the government that wishes to protect its citizens from potential hazards; and (3) the conventional medical community still questioning the safety and efficacy of these products. DSHEA does not appear to be the final verdict on herbal regulation, but just the first step in a long process of interpretation, evaluation, and decision-making required in the U.S. for regulation of any new class of such products. This paper reviews the current status facing the consumer, medical industry, and government in regards to herbal use.