Agricultural plastics area significant contributor to solid waste disposal problems, particularly in areas with heavy use of plastic-covered greenhouses or mulch films. Field-burning and landfilling are no longer viable options for disposal in many areas. Reuse and reduced weight of films are two methods to reduce the amount of material requiring disposal. Recycling, incineration, and on-site degradation appear to be the most-promising technologies for disposal. Each technology has its drawbacks. These include dirt and pesticide residues on mulch films, the presence of stabilizers and photoactivators, possible limitations to recycling mixtures of types of plastics, and high costs for recycling and incineration facilities. This is an active area of research for many members of the American Society for Plasticulture.
Sanitation, which includes removing plant and growing medium debris, is an important component of any greenhouse or nursery pest management program. However, there is minimal quantitative information on how sanitation practices can reduce pest problems. In this study, conducted from May through Nov. 2005, we evaluated plant and growing medium debris as a source of insect pests from four greenhouses located in central Illinois. Two 32-gal refuse containers were placed in each greenhouse with a 3 × 5-inch yellow sticky card attached to the underside of each refuse container lid. Each week, yellow sticky cards and plastic refuse bags were collected from the containers and insects captured on the yellow sticky cards were identified. Insects captured on the yellow sticky cards were consistent across the four greenhouses with western flower thrips (Frankliniella occidentalis), fungus gnats (Bradysia spp.), and whiteflies (Bemisia spp.) the primary insects present each week. Insect numbers, in order of prevalence on the yellow sticky cards, varied across the four locations, which may be related to the type of plant debris discarded. For example, extremely high numbers of adult whiteflies (range = 702 to 1930) were captured on yellow sticky cards in one greenhouse each month from August through November. This was due to the presence of yellow sage (Lantana camera), bee balm (Monarda didyma), garden verbena (Verbena × hybrida), common zinnia (Zinnia elegans), sage (Salvia spp.) and fuchsia (Fuschia spp.) debris that was heavily-infested with the egg, nymph, pupa, and adult stages of whiteflies. High western flower thrips adult numbers in the greenhouses were generally associated with plant types such as marguerite daisy (Dendranthema frutescens) and pot marigold (Calendula officinalis) disposed while in bloom with opened yellow flowers, which contained adult western flower thrips. Based on the results of this study, it is important that greenhouse producers timely remove plant and growing medium debris from greenhouses or place debris into refuse containers with tight-sealing lids to prevent insect pests from escaping.
disposal of nutrients and pesticides ( Montesano et al., 2010 ). This system can increase crop production through the higher water and fertilizer use efficiency, resulting in higher plant uniformity and anticipating the growth time ( Dumroese et al., 2006
disposing of PE mulch at landfills or other even less desirable disposal methods (e.g., burning). At the end of season, farmers remove PE mulch and dispose of it in landfills, stockpile it on the farm, or burn it on site ( Kasirajan and Ngouajio, 2012
, 2008 ). Proper disposal of harvested invasive plant parts is an important consideration because many invasive plants reproduce easily and successfully both sexually and asexually where any plant propagule could potentially produce new stands of plants
The widespread use and disposal of plastics are associated with significant environmental impacts, such as accumulation in landfills and the natural environment, and threats to wildlife via entanglement and ingestion ( Thompson et al., 2009a , 2009
and disposal of used plastic. Removal and disposal of used plastic can cost $250/ha ( Shogren, 2000 ). Several alternatives to reduce this cost have been evaluated by research teams throughout the world. Strategies have varied from the development of
Briassoulis, 2007 ; Steinmetz et al., 2016 ). PE mulch made from nonrenewable, petroleum-based feedstock is typically used for only one growing season before disposal ( Goldberger et al., 2015 ). The use of plastic mulches in agriculture has increased