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Crop-to-wild hybridization has the potential to introduce beneficial traits into wild populations. Gene flow from genetically engineered crops, in particular, can transfer genes coding for traits such as resistance to herbicides, insect herbivores, disease, and environmental stress into wild plants. Cultivated sunflower (Helianthus annuus) hybridizes spontaneously with wild/weedy populations (also H. annuus), but little is known about the relative fitness of [F.sub.1] hybrids. In order to assess the ease with which crop-to-wild introgression can proceed, we compared characteristics of [F.sub.1] wild-crop progeny with those of purely wild genotypes. Two nontransgenic, cultivated varieties were crossed with wild plants from three different regions - Texas, Kansas, and North Dakota. Seed burial experiments in the region of origin showed that wild-crop seeds had somewhat higher germination rates (less dormancy) than wild seeds from Kansas and North Dakota, while no differences were seen in seeds from Texas. Progeny from each type of cross were grown in outdoor pots in Ohio and in a weedy field in Kansas to quantify lifetime fecundity and flowering phenology. Flowering periods of hybrid and wild progeny overlapped considerably, especially in plants from North Dakota and Texas, suggesting that these hybrids are very likely to backcross with wild plants. In general, hybrid plants had fewer branches, flower heads, and seeds than wild plants, but in two crosses the fecundity of hybrids was not significantly different from that of purely wild plants. In Ohio, wild-crop hybrids from North Dakota appeared to be resistant to a rust that infected 53 % of the purely wild progeny, indicating a possible benefit of 'traditional' crop genes. In summary, our results suggest that [F.sub.1] wild-crop hybrids had lower fitness than wild genotypes, especially when grown under favorable conditions, but the [F.sub.1] barrier to the introgression of crop genes is quite permeable. Key words: Asteraceae; crop-weed hybrids; fecundity; fitness; flowering phenology; gene flow; introgression; seed dormancy; sunflower.

Spotted ( Diabrotica undecimpunctata howardi) and striped ( Acalymma vittata) cucumber beetles are significant pests of cucurbits, and organic management options are limited. Beetle feeding results in aesthetic damage and reduction in marketable yields as well as transmission of bacterial wilt resulting in plant mortality. Biopesticides are formulated from naturally occurring organisms such as fungi and bacteria that are pathogenic or toxic to insect pests and may be used in organic production systems. These products are thought to have lower risk to non-target organisms including mammals and beneficial insects. This research examined the potential of novel microbial products and fungal organisms to reduce cucumber beetle damage on melons. Laboratory bioassays were performed to evaluate the efficacy of a bacterial extract of Chromobacterium subtsugae and two common strains of entomopathogenic fungi, Beauveria bassiana and Isaria fumosorosea, on cucumber beetles in a controlled environment. Trials were performed against adult beetles in organic field experiments on muskmelon ( Cucumis melo L. cv. reticulatus Ser.). Prior to testing in the field, anti-feedant effects were observed when beetles were exposed to leaves with Chromobacterium subtsugae and Beauveria bassiana in the laboratory. However, in field applications, we did not observe a reduction in beetle populations below the economic threshold levels, and subsequently, there was no yield increase compared to the control. Additional research is needed to improve biopesticide efficacy through formulation and timing of delivery, determine efficacy on multiple life stages of the pest, and understand interactions of microbial biopesticides in the environment and potential for non-target impacts in organic systems. [ABSTRACT FROM AUTHOR]

This study investigated bee visitation on 10 agricultural crops grown on diverse small farms in Tennessee to determine the abundance of native bees and honey bees and the partitioning of visitation among crops. Summaries for each crop are used to generate mean proportions of bee visitation by categories of bees. This shows that native bee visits often occur as frequently, or in greater proportions than non-native honey bee visits. Visitation across multiple crops is then analyzed together with nonmetric multidimensional scaling to show how communities of bees that provide crop pollination change depending on the crop. Within squash and pumpkin plantings, continuous and discrete factors, such as "time of day" and "organic practices," further explain shifts in the community composition of flower visitors. Results from this study show that native bees frequently visit flowers on various crops, indicating that they are likely contributing to pollination services in addition to honey bees. Furthermore, the community of bees visiting flowers changes based on crop type, phenology, and spatial-temporal factors. Results suggest that developing pollinator conservation for farms that grow a wide variety of crops will likely require multiple conservation strategies. Farms that concentrate on a single crop may be able to tailor conservation practices toward the most important bees in their system and geographic locale. [ABSTRACT FROM AUTHOR]

The use of polyethylene mulch in vegetable production is considered unsustainable because of its contribution to soil plastic pollution. Plastic biodegradable mulches (BDMs) are a more sustainable option because they are tilled into the soil or composted at the end of the cropping season, and designed to decompose into water, carbon dioxide, and microbial biomass, reducing soil plastic pollution. Regardless of the potential environmental benefits associated with the use of BDMs, farmers will have to evaluate the changes in profits when transitioning from polyethylene (PE) mulch to BDM before deciding to adopt BDMs. This study evaluates the factors associated with the economic feasibility of adopting BDM in pumpkin production using a partial budget and sensitivity analyses. Results suggest that the cost of BDM, labor costs, and sale price discounts, due to mulch adhesion in pumpkin fruit have the greatest impact on profits when transitioning from PE mulch to BDM. When assuming current market prices for PE mulch and BDM, the 2019 Tennessee Adverse Effect wage rate, and no price discounts, transitioning from PE mulch to BDM results in a positive impact on profits. When assuming a 5% price discount, this transition results in a negative impact on profits. [ABSTRACT FROM AUTHOR]