Effects of Carriers, Emulsifiers, and Biopesticides for Direct Silk Treatments on Caterpillar Feeding Damage and Ear Development in Sweet Corn.

In the northeastern United States, control of Lepidopteran pests of sweet corn, particularly corn earworm [Helicoverpa zea (Boddie)], is difficult using organic methods. The direct application of corn oil and Bacillus thuringiensis (Bt) to corn silk has been shown to reduce ear damage from corn earworm in past studies; these studies sought to optimize this method by evaluating additional carrier and biopesticide mixtures that comply with the United States Federal Insecticide, Fungicide, and Rodenticide Act and National Organic Standards. Carriers, which are liquids used to dissolve the biopesticide and deliver it into the tip of the ear, may have phytotoxic or insecticidal properties. Experiments conducted from 2001 to 2005 evaluated caterpillar damage and ear development effects from carriers (vegetable and paraffinic oils and carrageenan), biopesticides (Bt, spinsosad, and neem), and three emulsifiers in various combinations when applied directly to the tips of the ears 5-7 d after silk initiation. There were no effects of emulsifiers on ear quality, except for slight reduction in caterpillar damage in one of the two years. There were no differences among corn, soy, canola, and safflower oils in corn earworm control or tip development. The carrageenan carrier had the least effect upon ear development as measured by the length of nonpollinated kernels at the tip, compared to corn oil or paraffinic oil (JMS Stylet Oil), which caused the greatest tip damage as well as an oily discoloration. The carrier-pesticide combinations with the best ear quality overall were spinosad in carrageenan or corn oil, and Bt in carrageenan.

Evaluation of oils and microbial pathogens for control of lepidopteran pests of sweet corn in New England.

Vegetable and mineral oil, Beauveria bassiana (Balsamo) and Bacillus thuringiensis subsp. kurstaki Berliner were evaluated for control of Ostrinia nubilalis (Hübner) (Lepidoptera: Pyralidae), Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) and Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in sweet corn (Zea mays L.). Field experiments in Maine and Massachusetts during 1993 and 1994 evaluated oils and pathogens singly or in combinations, using a single application directly to the top of the silk channel, immediately after pollination. Mineral oil alone provided equal (1993) or better (1994) control compared with corn oil. In both years, mineral or corn oil plus B. thuringiensis resulted in 93-98% marketable ears, compared with 48-52% marketable ears in untreated plots. In three factorial experiments with B. bassiana, B. thuringiensis and corn oil, B. bassiana at 5 x 10(7) conidia per ear provided little or no control while B. thuringiensis and corn oil provided significant though not always consistent control of all three species. The combination of B. thuringiensis and corn oil provided the largest and most consistent reduction in numbers of larvae and feeding damage to ears.

Insect herbivores as potential causes of mortality and adaptation in gallforming insects.

Recent studies have suggested that plant galls benefit only the insects living in them and not the host plants, and that galls are induced by insects primarily to improve the plant as a microenvironment or a food source. The potential advantage to insects of protection from their predators and parasitoids has been considered unclear and perhaps minor in importance. However, the potential threat to gallforming insects from other insect herbivores has usually been relatively neglected. This paper notes literature and observations which suggest that herbivores may either consume or be deterred by galls. Even soft leaf galls produced by Hormaphis and Phylloxera aphids appeared to deter some herbivores in the field. The threat of herbivory to galls might help explain general patterns of gall ecology and morphology, and deserves closer attention.

A Physiologic Profile Comparing Levels and Styles of Female Dancers.

In brief: A physiologic profile comparing 39 female dancers was undertaken to better understand the factors distinguishing four levels and styles of dance: professional ballet (PB), professional modern, university ballet, and university modern. The PB dancers had significantly lower VO2 max values on the tread-mill as well as lower peak blood lactate levels following the Wingate test for anaerobic capacity than the other dancers. The PB dancers also had a significantly higher isokinetic hamstring-quadriceps ratio than the modern dancers. These findings suggest that physiologic capacity may differ among female dancers according to their levels and styles of dance.