Phương pháp cơ học và hóa học (Chương 12, 13, 14, 16, và 20) là các thủ tục quản lý chính cho các nhà máy thủy sản phiền toái. Họ thường là những thành công, thường đắt tiền, và thường xuyên cung cấp kiểm soát tương đối ngắn hạn. Có một nỗi sợ hãi phổ biến rộng rãi, đôi khi chính đáng, thuốc diệt cỏ. Cơ khí / vật lý kỹ thuật có thể được làm chậm, không hiệu quả, đến sự tan vỡ, và có thể lây lan phá hoại. Không có loại của phương pháp chọn lọc, nhưng. | 17 Phytophagous Insects Fish and Other Biological Controls INTRODUCTION Mechanical and chemical methods Chapters 12 13 14 16 and 20 are the primary management procedures for nuisance aquatic plants. They are often successful usually expensive and frequently provide only relatively short-term control. There has been a widespread sometimes justified fear of herbicides. Mechanical physical techniques can be slow ineffective subject to breakdowns and may spread the infestation. Neither type of method is selective but instead provides temporary elimination of most plants including the target plant usually producing habitat removal instead of restoration of the community to a prior and more desirable condition. Eight exotic aquatic plants have proliferated in lakes of North America and elsewhere. They are Hydrilla Hydrilla verticillata . Royle Water hyacinth Eichhornia crassipes Mart. Solms-Laubach Alligatorweed Alternanthera philoxeroides Mart. Griseb. Eurasian watermilfoil Myriophyllum spicatum L. Floating Fern Salvinia molesta . Mitchell and Waterlettuce Pistia stratiotes L. curly leafed pondweed Potamogeton crispus L and Brazilian elodea Egeria densa Planch. Anacharis densa Planch. Vict. . Their success is due to invasions of highly favorable often disturbed habitats where biological controls are limited or absent rather than a response to eutrophication. The problem is acute in southern . states where there is an abundance of shallow warm naturally fertile aquatic habitats and a long growing season. The widespread economic damage and inconvenience caused by these plants coupled with dissatisfaction with mechanical and chemical methods has led to the development of biological controls including phytophagous insects and fish plant pathogens such as fungi and viruses and allelopathy. Biological controls including food web manipulations Chapter 9 and use of barley straw for management of algal biomass are not without problems including slow response .
