John D. Pesek

Comparing Willingness to Pay for Organic, Natural, Locally Grown, and State Marketing Program Promoted Foods in the Mid-Atlantic Region

A choice experiment of Mid-Atlantic consumers was conducted to determine marginal willingness to pay for the attributes organic, natural, locally grown, and state marketing program promoted for strawberry preserves. The influence of purchasing venue on willingness to pay was also examined. Results indicated a price premium when purchased at a farmers market across all five states and versions. Organic was preferred to natural in only one state. Preference ordering between local and state program promoted varied. Consumers in Maryland and Pennsylvania clearly preferred local, while those in New Jersey seemed most likely to prefer the state program version.

Copulatory courtship signals male genetic quality in cucumber beetles

In the spotted cucumber beetle, Diabrotica undecimpunctata howardi (Coleoptera: Chrysomelidae), males court females during copulation by stroking them with their antennae. Stroking occurs exclusively during the first stages of copulation, after a male has penetrated a females vaginal duct but before he is allowed access to her bursa copulatrix. Females accept the spermatophore of fast–stroking males and reject those of slow–stroking males by relaxing or constricting muscles distorting the vaginal duct. Here, we measure the repeatability of stroking behaviour within males, examine the effect of losing one antenna on male attractiveness and test whether such female control results in direct phenotypic benefits for the discriminating female or indirect genetic benefits that appear in her offspring. We also use a half–sibling design to quantify the variance and heritability of stroking speed and endurance. Female beetles were paired with a male that was known to stroke either quickly or slowly. No difference was found in the resulting fecundity or egg–hatching rate of the females, or in the survivorship, development rate, size, age at first reproduction or fecundity of their offspring indicating that no direct benefits are gained by discriminating among males on the basis of stroking speed. There were, however, good–genes benefits for the mates of fast–stroking males. Offspring of fast–stroking fathers were also fast strokers and were more likely to be accepted as mates than offspring of slow–stroking fathers. There was substantial variance among sires in stroking speed and endurance and the heritability of each trait was high. The antennal stroking rate was highly repeatable in successive mating attempts and males with only one antenna were not accepted as mates. The repeatability within males, variability between males and heritability between generations of copulatory stroking combine to provide females with a reliable and honest signal of the genetic quality of courting males.

Dispersal and Movement Behavior of Neonate European Corn Borer (Lepidoptera: Crambidae) on Non-Bt and Transgenic Bt Corn

ABSTRACT Neonate movement and dispersal behavior of the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), were investigated under controlled conditions on Bacillus thuringiensis (Bt) and non-Bt corn, Zea mays L., to assess plant abandonment, dispersal from their natal plant, and silking behavior after Bt and non-Bt preexposure. With continuous airflow, neonates on a Bt corn plant for 24 h abandoned that plant 1.78 times more frequently than neonates on a non-Bt corn plant. Indirect evidence indicated that at least one third of the neonates were capable of ballooning within 24 h. In the greenhouse, some neonates were recovered after 24 h from plants 76 and 152 cm away that likely ballooned from their natal plant. After 1 h of preexposure on a Bt corn leaf, neonates placed on a new corn leaf and observed for 10 min began silking off of a new Bt leaf significantly sooner than a new non-Bt leaf. Results suggest that neonates are unable to detect Bt in the corn within 10 min but that they can detect it within the first hour.

Ground-Dwelling and Foliar Arthropods in Four Cropping Systems

Abstract Four different corn, soybean, and wheat cropping systems were established in small replicated plots and simultaneously in larger (4-hectare) unreplicated fields. Each system was subject to distinct tillage practices, fertility programs, and methods of pest control, based on methods currently in use on farms in the Mid-Atlantic region of the United States. Ground-dwelling arthropods (mostly Carabidae and spiders) were sampled during the fourth and sixth growing season after the establishment of the plots, and foliar insects (pest and beneficial) and pest damage were sampled on corn in the sixth growing season. Overall, beneficial arthropod populations were lowest and corn pest insect populations (especially Western corn rootworms, Diabrotica virgifera virgifera LeConte) were highest in the simplest, most intensively managed continuous corn system, which had annual use of soil insecticides. Generally ground-dwelling species were higher in soybeans than in corn, and in no-till than in deep-tilled crops. Growers wishing to enhance populations of beneficial insects should consider predominantly no-till cropping systems with several different crops in the rotation and minimal insecticide use. For both ground and foliar sampling, patterns of abundance among systems and crops in the small replicated plots generally followed those observed in the large fields, but numbers of spiders and carabids collected per pitfall trap were generally much higher in the large fields.

Bioluminescence in firefly larvae: A test of the aposematic display hypothesis (Coleoptera: Lampyridae)

We investigated the hypothesis that bioluminescence in firefly larvae (Coleoptera: Lampyridae) functions as an aposematic display. In two experiments, we confirmed the distastefulness of firefly larvae, and tested the hypothesis that a naive, nocturnal predator can learn to use light signals as aposematic cues for avoiding distasteful prey. Larvae were rejected as acceptable prey by 100% of the house mice (Mus musculus) tested. Mice learned to avoid bitter food associated with light cues significantly faster (P=0.003) than mice presented with food lacking light cues. We conclude that luminescent glowing in firefly larvae meets the requirements of an aposematic signal.

Consumer Likelihood to Purchase Chickens with Novel Production Attributes

Typical supermarket chickens are produced with novel or controversial attributes. This continues despite contrasting growth in consumer interest in organic and natural foods. This study surveyed Delaware consumers’ likelihood to purchase chicken given different attributes: free range, given antibiotics, irradiated, fed genetically modified (GM) fee, GM chicken, and price. Examining conjoint analysis data with a heteroskedastic two-limit tobit model, GM chicken and other novel attributes were found to lower purchase likelihood significantly. Understanding these results should help the industry meet consumer preferences while aiding its continued expansion to benefit workers and growers across the South.

Performance Results and Characteristics of Adopters of Genetically Engineered Soybeans in Delaware

Genetically engineered (GE) soybeans first became available to farmers in 1996. Despite the common questions regarding any new crop technology, the new seeds were rapidly adopted. This study examines the characteristics of adopters, as well as yield and weed control cost changes, using survey results from Delaware farmers at the start of the 2000 season. Duration analysis reveals that earlier-adopting farmers had larger farms and tended to use computers for financial management, while regression analysis shows significantly lower weed control costs and, to a lesser extent, higher yields for GE soybeans.

Hormonal Control of Egg Dumping and Guarding in the Lace Bug, Gargaphia solani (Hemiptera: Tingidae)

This study examines the effect of juvenile hormone (JH) or a similarly acting juvenoid on the expression of maternal egg guarding and its life history alternative, egg dumping, in the lace bug, Gargaphia solani Heidemann. JH manipulations were indirect: methoprene, a synthetic JH analog, and precocene II, an allatocidal phytochemical commonly used to reduce JH synthesis, were applied exogenously to test the hypothesis that high JH titers promote egg production and egg dumping behavior, while low titers terminate egg production and initiate maternal care. As predicted, egg dumpers treated with precocene II ignored dumping opportunities and became egg guarders. Similarly, egg guarders that were treated with methoprene became gravid within 2 days and abandoned their eggs to become egg dumpers. These manipulations suggest that hormones can trigger the expression of both egg dumping and egg guarding in G. solani even when environmental conditions are inappropriate.

Effects of Varying Weed Communities in Corn on European Corn Borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), Oviposition, and Egg Mass Predation

Abstract Recent advances in weed control technology have changed how vegetational diversity can be managed in agroecosystems. This 2-yr study assessed the impact of altering the timing of herbicide application in herbicide-resistant field corn on the European corn borer, Ostrinia nubilalis (Hübner), and on the beneficial insects that prey on O. nubilalis egg masses. Treatments in this study were intended to allow weed presence in the field for varying periods of time, but control the weeds before crop yield was negatively impacted. Effects on O. nubilalis oviposition were assessed directly by counting egg masses and indirectly by assessing damage to corn stalks resulting from O. nubilalis infestations. The impact of weeds on the main generalist predators in this system was quantified through direct counts and predation trials on sentinel egg masses. In this study, altering the timing of herbicide application in herbicide-resistant field corn did not appear to affect the oviposition preference of O. nubilalis or the beneficial insects that prey on its egg masses. End-of-season stalk comparisons showed no differences in O. nubilalis infestation levels among the treatments. Predation on sentinel egg masses showed few significant differences among treatments, and predator densities were only rarely significantly different by treatment and showed no evident trends. Thus, our data suggest that under the conditions of this experiment, manipulating herbicide applications to minimize O. nubilalis damage is not a viable management technique in field corn.

Assessment of Chrysoperla plorabunda Longevity, Fecundity, and Egg Viability When Adults Are Fed Transgenic Bt Corn Pollen

Abstract The widespread planting of transgenic corn containing Bacillus thuringiensis (Bt) Cry endotoxin in its tissues for insect pest control raises the potential for influence on many non-target species including pollen-feeding species of Chrysopidae. This study was conducted to assess fitness parameters associated with longevity, fecundity, and egg viability of adult Chrysoperla plorabunda (Fitch) (Neuroptera: Chrysopidae) when fed Bt corn pollen. Bt products tested with their respective non-Bt near-isolines were Event 176 (Cry1Ab), MON810 (Cry1Ab), and TC1507 (Cry1F). Females fed pollen from Event 176 lived significantly longer than those fed pollen from its non-Bt near-isoline. Males fed pollen from TC1507 showed a trend for living longer than males fed its non-Bt near-isoline pollen, but there was no difference for females regarding this event. The mean number of eggs produced per female per day was significantly less for those fed MON810 pollen compared with females fed pollen from the non-Bt near-isoline. Total egg production was significantly less for females fed MON810 pollen vs. females fed pollen from its non-Bt near-isoline.