Experimental evidence is lacking to demonstrate whether Fusarium verticillioides (synonym = Fusarium moniliforme J. Sheld.; teleomorph = Gibberella fujikuroi (Sawada) Ito in Ito & K. Kimura, mating population A) functions as a causative agent or an opportunistic invader in seed (caryopsis) rot of maize (Zea mays L.). Previous researchers have isolated this fungus, along with many other microorganisms, from seed collected in the field long after rot commenced. The current investigations used an isolate of F. verticillioides transformed with a selectable marker and a reporter gene to inoculate previously disinfected maize seed. Seed rot developed, and F. verticillioides containing the introduced genes was isolated from inoculated, but not noninoculated, seed. Efficacy of Plantpro-45, an agent with an iodine-based active ingredient (a.i.), was analyzed for controlling growth of F. verticillioides from conidia and inoculated maize seed. A solution containing <10 µg a.i./mL inhibited growth of conidia suspended for <30 s. Furthermore, seed rot was controlled without diminishing seedling survival at 10 mg a.i./kg maize seed. Thus, F. verticillioides can function as the causative agent of maize seed rot and can be suppressed and (or) controlled at the postinfection stage with Plantpro-45.Key words: mycotoxin, reporter gene, germination, iodine.

Experimental and theoretical study of the B-Ne nonbonding interaction: The freebound B 2Σ+-X 2Π electronic transition Fluorescence depletion techniques were used to test vibronic and rotational assignments for the B 2 ⌺ Ϫ -X 2 ⌸ transition of CH-Ne. Previous vibronic assignments ͓W. H. Basinger, U. Schnupf, and M. C. Heaven, Faraday Discuss. 97, 351 ͑1994͔͒ were confirmed, and observations of transitions to dissociation continua provided accurate dissociation energies for the B and X states. Errors in the rotational assignments were discovered. Re analysis of the rotational structure yielded ground state parity splittings and improved rotational constants. Adiabatic model calculations were used to determine approximate angular potential energy curves for the B and X states. These calculations also accounted for the prominent optical activity of internal rotation in the spectrum.

No abstract

Plantpro 45, an iodine-based compound, was evaluated as a seed treatment for management of fusarium wilt caused by Fusarium oxysporum f.sp. basilici on basil (Ocimum basilicum) in greenhouse assays and for effects on growth of the pathogen in vitro. Plantpro 45 at a concentration of 300 mg·L-1 (ppm) prevented fusarium hyphal growth in vitro. Seed treatments of 800 to 1000 mg·L-1 eliminated fungal contamination of seed and increased germination by 27% compared to the nontreated control. Basil transplants grown from seed treated with 400, 800, and 1000 mg·L-1 were significantly taller, weighed more, exhibited larger leaf area, and had reduced wilt severity in the greenhouse compared to the nontreated control. Transplants grown in soil treated with increasing concentrations of Plantro 45 had correspondingly decreased wilt severity, regardless of whether or not the seeds had been previously treated with Plantpro 45. Further research and optimization of soil and foliar applications in combination with seed treatments are needed to provide a complete program for management of fusarium wilt of basil.

The A2delta-X2pi transition of CH-Ne was examined using laser-induced fluorescence and fluorescence depletion techniques. The spectrum was found to be particularly congested due to the large number of bound states derived from the CH(A,n=2)+Ne interaction, and the small energy spacings between these states resulting from the relatively weak anisotropy of the van der Waals bond. High-level ab initio calculations were used to generate two-dimensional potential energy surfaces for CH(X)-Ne and CH(A)-Ne. The equilibrium structures from these surfaces were bent and linear for the X and A states, respectively. Variational calculations were used to predict the bound states supported by the ab initio surfaces. Empirical modification of the potential energy surfaces for the A state was used to obtain energy-level predictions that were in good agreement with the experimental results. Transitions to all of the optically accessible internal rotor states of CH(A,n=2)-Ne were identified, indicating that CH performs hindered internal rotations in the lowest-energy levels of the A and X states. The characteristics of the potential energy surfaces for CH-Ne in the X,A,B, and C states suggest that dispersion and exchange repulsion forces dominate the van der Waals interaction.