Jeremiah D. Lowe

Nosema apis infection in honey bee (Apis mellifera) queens

Summary Queen honey bees were fed Nosema apis spores in sucrose solution, returned to their hives, and examined later for N. apis infection by a polymerase chain reaction test. Eggs, larvae and pupae from the hives were also examined for infection on three observation dates during a 39 day period following the inoculation of the queens. Six of seven surviving queens developed N. apis infections in their ventriculi, but none had detectable N. apis in their ovaries. No eggs, larvae or pupae taken from the hives of Nosema inoculated queens contained detectable N. apis. These results suggest that N. apis is not transmitted vertically, unlike many other Microsporidia in other invertebrate hosts. In an effort to determine if the stress of shipping increased the susceptibility of Nosema exposed bees, another set of mated, queen honey bees was fed N. apis spores in sucrose, and the queens were then either mailed in small shipping cages, from Kentucky to Indiana and back, or kept caged for the same period in the laboratory. These queens were then dissected and their ovaries and ventriculi examined for N. apis. Of the mailed queens, all developed infection, whilst 86% of the queens not mailed became infected, but this difference was not statistically significant. N. apis was not detected in any of the ovaries of mailed queens nor of those queens not mailed.

Clonality of Pawpaw (Asimina triloba) Patches in Kentucky

Abstract Pawpaw [Asimina triloba (L.) Dunal] is a tree-fruit (see overleaf, page 2) native to the southeastern region of the United States. Kentucky State University serves as the USDA-National Clonal Germplasm Repository for pawpaw, therefore assessing genetic diversity across the pawpaws native range is a high priority. Pawpaw is usually found in large patches as an understory tree and root suckering likely occurs. To determine if native pawpaw patches are clonal, DNA was extracted from leaf samples collected from trees in six native patches in three counties in central Kentucky. Two ISSR-PCR primers yielded three polymorphic and six monomorphic markers in the six patches. Three patches did not display any polymorphic markers in each patch, suggesting they were clonal. However, three other patches did show polymorphic markers within each patch, indicating these patches were not clonal and contained trees of at least two genotypes within each patch. This study suggests that to assess the genetic diversity of a pawpaw patch or local population, more intensive sampling strategies will be required.

Potential of Ripe Pawpaw Fruit Extract as an Insecticide and Feeding Deterrent for Striped Cucumber Beetle (Coleoptera: Chrysomelidae) on Squash

Laboratory experiments were performed to study the effects of pawpaw, Asimina triloba (L.) Dunal, fruit extract on mortality and feeding deterrence of striped cucumber beetle, Acalymma vittatum (F.). Recently, fruit tissues of pawpaw were found to contain phenolic and antioxidant compounds, as well as annonaceous acetogenin compounds having insecticidal activity. Ripe pawpaw fruit pulp from a range of pawpaw varieties was extracted with 100% ethyl alcohol to obtain acetogenin compounds. Pulp extracts of 0, 10, 100, 1,000, 10,000 and 50,000 ppm were then used to assess feeding deterrence and mortality of beetles. Buttercup squash leaf disks 3.5 cm in diameter were treated individually with each concentration and placed on water moistened filter paper in plastic Petri dishes (9 cm diam). Five striped cucumber beetles were placed on each leaf disk. All Petri dishes were then placed in an environmental growth chamber at 27°C and a 16:8 h light:dark photoperiod. Feeding activity was recorded 1, 4 and 24 h after beetle introduction. After 24 h the beetles were removed. Beetles did not feed on treated squash leaves at either 1 or 4 h of exposure. However, significant feeding occurred between 4 and 24 h after beetle introduction. Feeding was lowest and feeding damage least on 50,000 ppm pawpaw-treated leaf disks compared with leaf disks treated with < 10,000 ppm dilutions. Pawpaw fruit extract reduced feeding by 89% and 97% in the 10,000 and 50,000 ppm treatments, respectively. The calculated LC50 value was 50,538 ppm whereas the LCF10 (concentration at which only 10% of the leaves were consumed) was 2,033 ppm. At 10,000 ppm 10% of the beetles were killed; however, only 3% of the leaf tissue was consumed. Thus, pawpaw fruit extract may be an effective insect feeding deterrent. The duration of treatment effectiveness and susceptibility of other pest and beneficial insect species to the extracts also needs to be examined.

The Pawpaw Peduncle Borer, Talponia plummeriana Busck (Lepidoptera: Tortricidae): A Pest of Pawpaw Fruit

ABSTRACT The pawpaw peduncle borer, Talponia plummeriana Busck (Lepidoptera: Torticidae), is a pest of pawpaw flowers often boring into the peduncle and causing flower drop. Here we document the first occurrence of this insect infesting ripe pawpaw fruit. Infested fruit that had been collected at the Kentucky State University Research and Demonstration Farm in Franklin County, Kentucky were dissected and small tan colored larvae with brown head capsules were discovered in the fruit. Pawpaw peduncle borer adults were reared from fruit held at room temperature in the laboratory.

Pawpaw Patch Genetic Diversity, and Clonality, and its Impact on the Establishment of Invasive Species in the Forest Understory

ABSTRACT The pawpaw (Asimina triloba) is a native understory tree of 26 states of the Eastern and Midwestern United States. Pawpaws genetic diversity and clonality in relation to this trees ability to compete with local invasive species in Kentucky has not been examined. The objectives of this study were two-fold: to determine the genetic diversity and clonality displayed in seven native pawpaw patches located at the Kentucky State University Environmental Education Center (KSU-EEC), The Kentucky River, Cove Spring Park, and the KSU Research and Demonstration Farm in Franklin County using DNA microsatellite markers; and to determine if patches reduced the incidence of invasive species. Twenty-five trees from seven patches in the four different locations were sampled for genetic analysis. Leaf samples were extracted using the DNAmite Plant Extraction Kit and products from four microsatellite loci were analyzed using a 3130 Applied Biosystems Gene sequencer. String grids were created and invasive plants c...

Genetic Diversity in Kentucky Spicebush Populations using Simple Sequence Repeat Markers

ABSTRACT Spicebush (Lindera benzoin L.) is a small native shrub that grows in the moist, understory areas of Appalachia and has potential as a new niche crop for small farmers. Native Americans and early settlers used this plant traditionally as a tea, and used the berries for jam, to spice food, and possibly for health benefits. Native spicebush patches may serve an important role in forest ecosystems in terms of fruit production for animals, soil erosion control, and enhancing insect biodiversity. Spicebush may also serve to hold ecological niches by outcompeting invasive plants compared to those in unchallenged areas. Genetic diversity of native spicebush populations in Kentucky has not been examined. The objective of this study is to determine the genetic diversity in spicebush populations in Kentucky using simple sequence repeat (SSR) DNA marker systems. Leaf samples were collected from 120 spicebush plants in the forests at the Kentucky State University Environmental Education Center (EEC), at a loc...