Reduced fusarium ear rot and symptomless infection in kernels of maize genetically engineered for European corn borer resistance.

ABSTRACT Field experiments were conducted in 1994, 1995, and 1996 to evaluate the incidence and severity of Fusarium ear rot and the incidence of symp-tomless Fusarium infection in kernels of maize hybrids genetically engineered with Bacillus thuringiensis genes encoding for the delta-endotoxin CryIA(b). Treatments included manual infestation with European corn borer (ECB) larvae and insecticide applications to limit ECB activity to specific maize growth stages or mimic standard ECB control practices. Fusarium symptoms and infection were affected by the specific cryIA(b) transformation used in each hybrid that determines tissue-specific expression of CryIA(b). In hybrids expressing CryIA(b) in kernels, incidence and severity of Fusarium ear rot and incidence of symptomless kernel infection were reduced compared with near-isogenic hybrids lacking cryIA(b) genes. In plants that were manually infested with ECB, ear rot incidence was reduced by 87, 58, and 68%; severity was reduced by 96, 54, and 64%; and incidence of kernel infection by Fusarium species was reduced by 17, 38, and 38% in 1994, 1995, and 1996, respectively. Results were similar in treatments that were not manually infested, but differences between transgenic and nontransgenic hybrids were smaller. Most kernel infection was due to F. moniliforme, F. proliferatum, and F. subglutinans (section Liseola) collectively, and it was within this group that transgenic hybrids exhibited reduced infection. Expression of CryIA(b) in plant tissues other than kernels did not consistently affect Fusarium symptoms or infection. Disease incidence was positively correlated with ECB damage to kernels. Insecticide applications also reduced Fusarium symptoms and infection when applied to nontransgenic plants.

Migratory ecology of the black cutworm.

The long-range migration of insects in general is briefly discussed here and serves as an introduction for in-depth inquiry into the migratory ecology of Agrotis ipsilon, the black cutworm. Zoogeography, pest status and injury, and seasonal occurrence of the species are reviewed. Circumstantial evidence of long-range movement of A. ipsilon moths within both hemispheres is presented, followed by experimental evidence of long-range movement of A. ipsilon moths in China and North America. Based upon experimental evidence published by several investigators, a theory is proposed of the existence of a thermal range (0-36 degrees C) for A. ipsilon pupae that acts as the precursor for adult (moth) migration. This theory should help explain the circumstantial and empirical evidence gathered upon the annual appearance and disappearance of this species over large geographic areas.

Immunochemical quantitation, size distribution, and cross-reactivity of lepidoptera (moth) aeroallergens in southeastern Minnesota.

With an immunochemical method, we analyzed outdoor air samples during a 3-year period for concentrations of the predominant local species of moth, Pseudaletia unipuncta (Haworth). Airborne particulates were collected on fiberglass filter sheets with an Accu-Vol sampler located 1.5 m above ground on the southeastern Minnesota prairie. Filter eluates analyzed by RIA inhibition contained concentrations of moth protein peaking in June and August to September of each year, with levels comparable to reported immunochemically measured levels of pollen and mold allergens. These peaks also corresponded with total numbers of moths captured in light traps. Moth-allergen activity was distributed in particle sizes ranging from 0.8 to greater than 4.1 micron when sized samples were obtained by use of an Andersen cascade impaction head. By RIA inhibition, there was cross-reactivity between P. unipuncta and insects of different genera, families, and orders, but not with pollens or molds. Forty-five percent of 257 patients with immediate positive skin tests to common aeroallergens had positive skin tests to one or more commercially available whole body insect extracts. Of 120 patients with allergic rhinitis believed to be primarily caused by ragweed sensitivity, 5% also had elevated specific IgE to moths. We conclude that airborne concentrations of Lepidoptera can be measured immunochemically and that moths may be a seasonal allergen in the United States.