An Economic Analysis of Wild Bee Pollination in Lowbush Blueberry Production

The purpose of this project is to determine the relative economic values of wild bee pollinators and commercial honeybees in lowbush blueberry production for individual Maine farms. The lowbush blueberry requires insect pollination in order to set fruit. Most farmers rent colonies of the non-native honeybee for pollination services, but wild, native bees are also effective pollinators. This project aims to provide growers with the means to assess the pollination needs of individual fields and to understand the levels of pollination possible if honeybees are not available. In order to achieve these goals, the relative abundance and species diversity of native bees found foraging on blueberry flowers will be determined. This information, along with crop yield, will be used to calculate the economic value of native bees as a community and how much value to attribute to honeybees and common native bee groups. Native bee abundance and diversity will also be examined in relation to field characteristics and farm management practices. Workshops and on-farm trainings will provide farmers the means to assess their pollination needs and develop a sustainable pollination strategy based upon use of honeybees and/or native bees

Factors Responsible for Differences in Yield Among Lowbush Blueberry Clones

Identify factors that explain differences in yield among lowbush blueberry clones. Compare high yielding clones to low yielding clones for several factors. Factors include average genetic similarity with neighbors and effects of relationship of parents in controlled crosses on fruit set, synchrony of flowering time with neighbors, freezing tolerance of closed flower buds and open flowers, floral morphological and physiological differences (nectar amounts) that might be more attractive to bees, signs of disease, etc. Studies will focus on comparing high yielding clones to low yielding clones for several factors. Because V. angustifolium is predominantly outcrossing and self-fertility is poor due to earlyacting inbreeding depression, one of the factors that will be investigated is genetic relationship with neighboring clones. EST-PCR markers will be used to genotype clones and determine relationship (genetic similarity) to other clones. Crosses will be made between high yielding clones and other clones in the field that have clearly different similarity values. The same will be done with low yielding clones. In this way, it will be determined if genetic relationship affects yield. In addition, 4-5 clones in the immediate vicinity of each high and low yielder will be genotyped. The average similarity value between each focal high and low yielder and its neighbors will be determined and compared. Other factors will be compared between high and low yielding clones including synchrony of flowering time with neighbors, freezing tolerance of closed flower buds and open flowers, flower morphology, signs of disease, etc

Some Aspects of the Biology of a Predaceous Anthomyiid Fly, \u3ci\u3eCoenosia Tigrina\u3c/i\u3e

The results of a two-year study in Michigan on the incidence of Coenosia tigrina adults under different onion production practices is presented. In Michigan, C. tigrina has three generations and is more abundant in organic agroecosystems than chemically-intensive onion production systems

TB172: Evaluation of Entomopathogens for Biological Control of Insect Pests of Lowbush (Wild) Blueberry

To maintain the economic viability of Maine’s blueberry farms, to offer alternative pest control strategies in light of the implementation of the Food Quality Protection Act of 1996, and to reduce the human health and environmental risks associated with pest management, these researchers have been researching biological control tactics. This technical bulletin outlines protocols and experimental design necessary for evaluation of entomopathogens targeted against the significant direct and indirect pests associated with lowbush blueberry.https://digitalcommons.library.umaine.edu/aes_techbulletin/1035/thumbnail.jp

Fertilizer and fungicides: Effects on wild blueberry growth, insect attack, and leaf spot disease incidence

The goal of our three-year field study (two replicated two year trials) was to evaluate the influence of fertility and disease management practices commonly implemented by Maine wild blueberry growers during the prune year. Our treatments reflected grower practices. We tested applications of chlorothalonil (formulated as Bravo®), pyraclostrobin and boscalid (formulated as Pristine®), pyraclostrobin and boscalid with diammonium phosphate fertilizer (formulated as DAP®), and a non-treated control. Measured responses included sap-feeding hemipteran insects, fungal leaf spot pathogens, premature flowering, stem growth characteristics, flower bud cluster production, leaf retention, foliar nutrients, and yield. Among plant growth measures that represent potential yield, only stem length responded consistently over both trials. Plots treated with Pristine + DAP had significantly greater stem length compared to the other three treatments. Plots treated with Pristine only were not different than Bravo treated plots, but stems were significantly longer than the non-treated control. The fungicide, Pristine, and the fertilizer, DAP applied in the prune year enhanced leaf spot disease in both years; however, the combination of Pristine and DAP did not consistently effect yields. We found a significant and diverse community of sap-feeding hemipteran incidence in the 2016 trial, but not in the 2015 trial. Only in the 2016 trial did the Pristine and DAP treatment enhance sap-feeding bugs. Multivariate analysis of variance provided evidence that leaf spot pathogens and sap feeding insect pests responded positively to nitrogen concentration in foliage. We also found that fungicides do not compensate for the enhanced disease levels brought about by fertilizer application

TB147: Simulating the Development of Mexican Bean Beetle Immature Stages, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), on Dry Beans

A computer model was developed to simulate and predict the phenology of Mexican bean beetle (MBB), Epilachna varivestis Mulsant, populations on dry beans, Phaseolus vulgaris. Time-varying distributed developmental rates of the egg, four larval instars, and pupal stages were simulated with degree day models, based on a standardized cumulative probability distribution function from a range of constant temperature experiments. Predictions from the simulation model provided a good fit to the observed constant temperature data and field experiments. Using temperature data in the form of daily maximums and minimums, the model can be used to predict the occurrence of immature MBB stages under field conditions, when the frequency distribution of egg mass recruitment is known.https://digitalcommons.library.umaine.edu/aes_techbulletin/1204/thumbnail.jp

TB199: Ant–Homopteran Relationships: Relevance to an Ant Invasion in Maine

The richness and diversity of native ant species on Mt. Desert Island, Maine, have been reduced in areas infested with Myrica rubra (European red ant). In general, the success of invasive ant species has been attributed to interference and exploitative competition coupled with the ants’ opportunistic diets. In field experiments on Mount Desert Island, Maine, M. rubra discovered and recruited to baits faster than native ants. This study also showed that M. rubra displaced most native ant species from food resources (Garnas 2005). This, together with M. rubra’s aggressive defense of invaded territories, has led to fewer native ants in infested areas. The purpose of this literature review is to investigate ant–homopteran relationships and discuss the possibility of homopterans indirectly aiding ant invasions.https://digitalcommons.library.umaine.edu/aes_techbulletin/1004/thumbnail.jp

TB163: Insect Predation of Seeds and Plant Population Dynamics

This review provides a framework for understanding the mechanisms of insect seed predation, the diversity of insects that prey on seeds, and the ecological and evolutionary consequences of insect seed predation. Insect seed predation can play significant roles in reducing plant population growth, modifying intraspecific and interspecific competition, shifting spatial and temporal distribution, affecting species evolution, and plant community structure, both in natural and agricultural ecosystems.https://digitalcommons.library.umaine.edu/aes_techbulletin/1039/thumbnail.jp

Itty-bitty traps for monitoring spotted wing Drosophila (\u3cem\u3eDrosophila suzukii\u3c/em\u3e Matsumura), does size matter?

The objective of this study was to determine an optimal trap design and bait for spotted wing drosophila, Drosophila suzukii (Matsumura), in the wild blueberry agro-ecosystem. Two preliminary experiments were conducted in 2013 and 2014 to address this objective. In 2018, an experiment was conducted to evaluate the effect of the physical trap size, as perceived by the spotted wing drosophila, on trap capture efficacy. We found that the red Solo® cup trap was an optimal trap for monitoring spotted wing drosophila in wild blueberry and that inserting a yellow sticky card inside the trap or painting a black contrast ring around the top entrance holes resulted in no benefit. We also found in early experiments that the live yeast bait with sugar syrup either alone or with apple cider vinegar was a superior bait. Trap size affected trap capture abundance; when considering catches based on adjustments for bait volume or two-dimensional trap area, the small trap size was more efficient than the standard

TB192: The Use of Glyphosate Herbicides in Managed Forest Ecosystems and Their Effects on Non-target Organisms with Particular Reference to Ants as Bioindicators

This publication reviews and synthesizes the results of many research studies designed to elucidate the ecological effects of the herbicide glyphosate used in forested landscapes. We have not intended our review to be an exhaustive review of all published studies (both laboratory and field investigations) concerned with faunal and floral glyphosate interactions and the environmental fate of glyphosate. We particularly focused on studies that had relevance to north temperate forest ecosystems and selected published investigations to incorporate into our review that cover a wide range of faunal and floral taxa that might be exposed to herbicides during applications.https://digitalcommons.library.umaine.edu/aes_techbulletin/1016/thumbnail.jp