Sampling Soybean Looper on Soybean

Abstract

The absorption characteristics and mechanisms of pertechnetate (TcO47) uptake by hydroponically grown soybean seedlings (Glycinemax cv Williams) were determined. Absorption from 10 micromolar solutioDs was linear for at least 6 hours, with 30% of the absorbed TcO47 being transferred to the shoot. Evaluation of concentration-dependent absorption rates from solutions containing 0.02 to 10 micromolar TcO4-shows the presence of multiphasic absorption isotherms with calculated K, values of 0.09, 8.9, and 54 micromolar for intact seedlings. The uptake of TcO4-was inhibited by a 4-fold concentration excess of sulfate, phosphate, selenate, molybdate, and permangnate; no reduction was noted with borate, nitrate, tugstate, perrhenate, iodate, or vanadate. Analyses of the kinetics of interaction between TcO47 and inhibiting anions show permangnate to be a noncompetitive inhibitor, while sulfate, phosphate, and selenate, and molybdate exhibit characteristics of competitive inhibitors of TcO4-transport suggesting involvement of a common transport process. Technetium-99 is currently projected to be one of the most important isotopes associated with the nuclear fuel cycle based on potential long-term dose to man. This is based on a number of criteria including fission yield (6%), long half-life (2.13 x l0 year), mobility and persistence in soils as the pertechnetate ion (TcO4-), and its comparatively high availability for plant absorption (11, 19). Wildung et al. (18) have shown that TcO4-added to soil was readily accumulated by soybean and wheat seedlings over a 30-d period with reported CR2 values (CR = activity/g tissue dry weight. activity/g soil dry weight) of 380 to 170 for soil concentrations of0.001 to 0.1 Mg Tc/g soil. At concentrations above 0.1 Mg/g, severe toxicity and seedling death resulted. At soil concentrations of 1 pg Tc/g soil, CR values have been reported to range from 50 to 400 for cheatgrass and tumbleweed grown on arid soils (16). Landa et al. (12) showed a similar range in CR values for six plant species grown hydroponically and for wheat grown on 11 different soils. While CR values for TcO4-are high compared with values for fission products and non-nutrient pollutant elements (<1), they are of a magnitude observed for trace' nutrient ions such as Mo, Mn, Cu, Fe, and Zn (4). The solubility ofTcO4-in soils, although an important aspect of its soil-plant behavior, does not totally explain the high affinity of plants for TcO4-. The observed phytotoxicity of9Tc was investigated by Berlyn et al. (2). Their results failed to demonstrate cytological evidence ' Work performed for the United States Department of Energy under Contract DE-AC06-76RL0 1830. 2 Abbreviation: CR, concentration ratio. for radiation-induced damage and suggested an interaction or substitution of Tc for an essential nutrient. Pertechnetate has been shown to be toxic to a number of algae and bacteria, and interfere with both respiration and photosynthesis (9) at concentrations in excess of 1 mm. The potential interaction of Tc with nutrient...

Soybean Looper (Lepidoptera: Noctuidae) Oviposition on Cotton and Soybean of Different Growth Stages: Influence of Olfactory Stimuli

“…Soybean looper moths preferred to oviposit on the bottom surface of soybean and cotton leaves, as opposed to the upper surface, stems, blooms, squares, or pods. Herzog (1980) and Mascarenhas and Pitre (1997) reported similar observations. Eggs on the lower surface of leaves are provided some protection from adverse environmental conditions.…”

Attractiveness of binary blends of floral odorant compounds to moths in Florida, USA

“…Many of the moth species collected are economic pests in diverse cropping systems. Velvetbean caterpillar and soybean looper are important defoliators of soybeans and peanuts in the southeastern USA (Herzog & Todd, 1980; Herzog, 1980). Mocis spp.…”

Influence of induced resistance in soybean on the development and nutrition of the soybean looper and the Mexican bean beetle

“…MBB is an oligophagous insect and its host range is restricted within the plant family Leguminosae (Turnipseed & Shepard, 1980). SBL is a general plant feeder and its host range includes members of 28 plant families (Herzog, 1980). The role of induced factors in the resistance of soybean to herbivores is only beginning to be unravelled, but recent studies have shown that soybean resistance to the MBB increases in response to extrinsic stress factors, including UV radiation (Hart et al, 1983), mechanical injury and fungal cell wall suspension (Lin & Kogan, unpublished), and insect herbivory (Chiang et al, 1987;Lin & Kogan, unpublished).…”