Copper sulfate and other chelated or complex copper forms are commonly used to manage nuisance and noxious algae and invasive weeds through direct application to aquatic systems. Regulatory scrutiny and perceived non-...Copper sulfate and other chelated or complex copper forms are commonly used to manage nuisance and noxious algae and invasive weeds through direct application to aquatic systems. Regulatory scrutiny and perceived non-target species impacts supported the need for an accurate risk assessment of fate and effects of copper applied as a pesticide. Copper inputs to aquatic systems originate from numerous sources (e.g. natural, storm water, industrial) whereas direct pesticide applications account for approximately 13%. Following a pesticide application, copper rapidly partitions to suspended algae and particulates and the majority (>90%) of applied copper is transferred to sediments within 2 days. Copper subsequently shifts to less bioavailable forms and risks to non-target species are significantly decreased. Additionally, the copper that partitions to sediments is diluted through migration to greater sediments depths and accretion. Even when elevated sediment copper concentrations were measured following chronic applications or high treatment levels, no adverse effects to non-target species were observed with laboratory or field experiments. When used appropriately copper can be an effective tool for water resource managers with negligible environmental impact.展开更多
Water resource management programs designed to control nuisance algal infestations have historically been dominated by reactive approaches. With increased regulatory scrutiny regarding algaecide use, data regarding ef...Water resource management programs designed to control nuisance algal infestations have historically been dominated by reactive approaches. With increased regulatory scrutiny regarding algaecide use, data regarding efficacy of integrated management approaches are needed. This research outlines an efficient method of comparing management programs based upon exceeding designated algae action threshold levels (AATL) in pond systems. Phosphorus mitigating technologies were specifically evaluated as phosphorus had been indicated in supporting many nuisance algal types/densities. The objectives of this research were to evaluate pond management programs in terms of action thresholds exceeded, number of reactive algaecide treatments and algaecide amount required to maintain ponds below AATL. This research compared management programs consisting of: 1) Copper sulfate;2) SeClear Algaecide and Water Quality Enhancer;and 3) Phoslock phosphorus binding technology plus SeClear (as needed). Water and algae samples were analyzed every two weeks over two growing seasons on replicated research ponds and compared with designated AATL parameters. If an AATL was exceeded, then a reactive algaecide treatment was implemented for the corresponding water body. Ponds managed by copper sulfate alone exceeded a greater amount of AATL and required a significantly greater (P < 0.05) amount of reactive algaecide treatments to maintain control (average 6.5 annually) whereas SeClear and Phoslock plus ponds required 4.3 and 1.8 treatments, respectively. The average amount of copper applied to maintain ponds below AATL was 1414 g with copper sulfate whereas copper amendments were significantly decreased with SeClear (830 g) and even further with Phoslock plus management programs (342 g). Additionally, management programs incorporating nutrient mitigation required fewer treatments and less copper in year two of the program. This research provides valuable information for water resource managers to evaluate integrated approaches to water resource management in terms of social, economic, operational and regulatory viewpoints.展开更多
Sponge plant is an emerging threat that has spread throughout California including the Sacramento-San Joaquin Delta, which is an important water resource for agriculture as well as critical habitat for a variety of th...Sponge plant is an emerging threat that has spread throughout California including the Sacramento-San Joaquin Delta, which is an important water resource for agriculture as well as critical habitat for a variety of threatened and endangered species. More data are needed on effective control methods for this spreading invader, as current management practices are not preventing proliferation. The overall objectives of this research were to evaluate imazamox, penoxsulam, topramezone, florpyrauxifen-benzyl, and carfentrazone-ethyl for control of sponge plant using three testing scales, as well as compare image analysis software to traditional biomass response for measuring herbicide performance. Overall, 280 g imazamox ha−1 (with one-percent methylated seed oil surfactant) was found as a potent solution for all different growth stages of sponge plant, and 70 g penoxsulam ha−1 as an alternative for control of sponge plant in the seedling and rosette growth stage. The image analysis software yielded similar measurement of herbicide effects as traditional biomass measure. Mesocosm testing indicated imazamox treatment sites should be inspected at four week intervals to identify plants missed by prior applications. This research provides water resource managers critical information for identification of an aquatic invasive species, and selecting an effective rapid management program.展开更多
文摘Copper sulfate and other chelated or complex copper forms are commonly used to manage nuisance and noxious algae and invasive weeds through direct application to aquatic systems. Regulatory scrutiny and perceived non-target species impacts supported the need for an accurate risk assessment of fate and effects of copper applied as a pesticide. Copper inputs to aquatic systems originate from numerous sources (e.g. natural, storm water, industrial) whereas direct pesticide applications account for approximately 13%. Following a pesticide application, copper rapidly partitions to suspended algae and particulates and the majority (>90%) of applied copper is transferred to sediments within 2 days. Copper subsequently shifts to less bioavailable forms and risks to non-target species are significantly decreased. Additionally, the copper that partitions to sediments is diluted through migration to greater sediments depths and accretion. Even when elevated sediment copper concentrations were measured following chronic applications or high treatment levels, no adverse effects to non-target species were observed with laboratory or field experiments. When used appropriately copper can be an effective tool for water resource managers with negligible environmental impact.
文摘Water resource management programs designed to control nuisance algal infestations have historically been dominated by reactive approaches. With increased regulatory scrutiny regarding algaecide use, data regarding efficacy of integrated management approaches are needed. This research outlines an efficient method of comparing management programs based upon exceeding designated algae action threshold levels (AATL) in pond systems. Phosphorus mitigating technologies were specifically evaluated as phosphorus had been indicated in supporting many nuisance algal types/densities. The objectives of this research were to evaluate pond management programs in terms of action thresholds exceeded, number of reactive algaecide treatments and algaecide amount required to maintain ponds below AATL. This research compared management programs consisting of: 1) Copper sulfate;2) SeClear Algaecide and Water Quality Enhancer;and 3) Phoslock phosphorus binding technology plus SeClear (as needed). Water and algae samples were analyzed every two weeks over two growing seasons on replicated research ponds and compared with designated AATL parameters. If an AATL was exceeded, then a reactive algaecide treatment was implemented for the corresponding water body. Ponds managed by copper sulfate alone exceeded a greater amount of AATL and required a significantly greater (P < 0.05) amount of reactive algaecide treatments to maintain control (average 6.5 annually) whereas SeClear and Phoslock plus ponds required 4.3 and 1.8 treatments, respectively. The average amount of copper applied to maintain ponds below AATL was 1414 g with copper sulfate whereas copper amendments were significantly decreased with SeClear (830 g) and even further with Phoslock plus management programs (342 g). Additionally, management programs incorporating nutrient mitigation required fewer treatments and less copper in year two of the program. This research provides valuable information for water resource managers to evaluate integrated approaches to water resource management in terms of social, economic, operational and regulatory viewpoints.
文摘Sponge plant is an emerging threat that has spread throughout California including the Sacramento-San Joaquin Delta, which is an important water resource for agriculture as well as critical habitat for a variety of threatened and endangered species. More data are needed on effective control methods for this spreading invader, as current management practices are not preventing proliferation. The overall objectives of this research were to evaluate imazamox, penoxsulam, topramezone, florpyrauxifen-benzyl, and carfentrazone-ethyl for control of sponge plant using three testing scales, as well as compare image analysis software to traditional biomass response for measuring herbicide performance. Overall, 280 g imazamox ha−1 (with one-percent methylated seed oil surfactant) was found as a potent solution for all different growth stages of sponge plant, and 70 g penoxsulam ha−1 as an alternative for control of sponge plant in the seedling and rosette growth stage. The image analysis software yielded similar measurement of herbicide effects as traditional biomass measure. Mesocosm testing indicated imazamox treatment sites should be inspected at four week intervals to identify plants missed by prior applications. This research provides water resource managers critical information for identification of an aquatic invasive species, and selecting an effective rapid management program.
