TREND OF PHREATOPHYTE CONTROL IN ARID ENVIRONMENTS AND THE DEVELOPMENT OF CONTROL MONITORING AND EVALUATING
Authors: Junming Wang and Ted W. Sammis
Abstract: It has been necessary to control Phreatophytes by mechanical, chemical, and biological methods because the plants consume much more water than other plants and waste scarce water resources in arid areas. The conventional mechanical and chemical control approaches are costly ($1500-$1700/ha for mechanical control and $240-$550/ha for chemical control), and can cause collateral damage to natural resources, including unintended impacts to desirable plants. Another disadvantage of chemical control is the chemical pollution to rivers and ground water. An alternative tool for managing certain plant invaders is classical biological control, in which specialist herbivores that only feed on the target plant in its native environments are imported to suppress pest infestations Biological control uses beetles instead of pesticides to control phreatophytes. Therefore, it significantly protects environmental quality and reduces the risk of health problems and other problems associated with pest management. However, to date we have few data with which to evaluate the cost-effectiveness of biological control and compare it to other control methods. Evaluation and monitoring of the control results (infestation areas and water savings from ET reduction) are lacking because the scales of the controls, both spatial (e.g., over kilometers, thousands of hectares) and temporal (years), are large, and ground monitoring and evaluation are difficult and time- and laborconsuming. Efficient phreatophyte control requires a convenient and accurate evaluation and monitoring tool.