The ornamental crop industry in the United States, is a billion-dollar industry. Weed management in nursery container production is a significant challenge, as weeds compete with ornamentals for essential resources, reducing plant quality, marketability, and overall profitability. Controlling weeds in containers is one of the highest production costs encountered by nursery growers, often exceeding $4,000 per acre. Previous research results have shown that weeds within a restricted area can reduce ornamental growth by 60%. Some of the most problematic weed species identified in the container production includes liverwort, hairy bittercress, oxalis, chick weed, etc. Liverwort is one of the major weed problems in greenhouses and nursery container production. Historically liverwort has been reported as a weed issue in cooler regions of the Northeast and Pacific Northwest regions of the United States. It thrives well in moist, low UV light condition, and in presence of high fertility and a cool temperature. Hence, nurseries and greenhouses are ideal places for their growth. Growers rely mostly on hand weeding to manage these problematic weeds, especially inside the greenhouse production system as there are limitations in applying herbicides within greenhouse conditions. Since hand weeding is very time consuming, laborious, and expensive, there is an immediate need for research to improve chemical weed control practices through alternative pesticides that can be applied to container production and improve growers’ productivity and profitability. New plants are always being added to nursery production so phytotoxicity studies are also required. Some previous research has focused on evaluating synthetic versus organic herbicides for weed control inside greenhouse conditions. However, there is almost no information available on how alternative pesticides such as fungicide or miticides can be used for weed control in container production and whether they will be safe on ornamentals. This significant knowledge gap has led to the development of this master’s research proposal. Hence the objectives of this research proposal are: To evaluate the preemergence efficacies of fungicide and miticide as alternative pesticides on liverwort control; To assess newer herbicide formulations and rates for controlling weeds and phytotoxicity on container-grown woody shrubs; To disseminate the research results to the growers and scientific community. Preliminary results have shown that miticide Tetracurb Max and fungicide Zerotol can provide suppression of liverwort in containers without causing any significant injuries to the woody ornamental shrubs.
