**Alternatives to Synthetic Insecticides in the Control of the Colorado Potato Beetle (***Leptinotarsa decemlineata* **Say) and Their Environmental Benefits**

#### **Bastian Göldel \*, Darija Lemic and Renata Bažok**

Department of Agricultural Zoology, Faculty of Agriculture, University of Zagreb, Svetošimunska 25, 10000 Zagreb, Croatia; dlemic@agr.hr (D.L.); rbazok@agr.hr (R.B.) **\***Correspondence:bastian.goeldel@web.de

 Received: 3 November 2020; Accepted: 5 December 2020; Published: 8 December 2020

**Abstract:** In this study, we review the wide range of alternative control methods used to this day to control the Colorado potato beetle (*Leptinotarsa decemlineata* Say), the biggest potato pest globally. We further categorize and highlight the advantages and disadvantages of each method by comparing them to conventional insecticides. In a second step, we point out the current knowledge about positive and negative impacts of using alternative control methods. By this, we illustrate how alternative control methods, farmers' activities, and environmental factors (e.g., biodiversity and ecosystem health) are heavily linked in a cycle with self-reinforcing effects. In detail, the higher the acceptance of farmers to use alternative control methods, the healthier the ecosystem including the pest's enemy biodiversity. The following decrease in pest abundance possibly increases the yield, profit, and acceptance of farmers to use less conventional and more alternative methods. Overall, we try to balance the positive and negative sides of alternative control methods and combine them with current knowledge about environmental effects. In our view, this is a fundamental task for the future, especially in times of high species loss and increasing demand for environmentally friendly agriculture and environmentally friendly products.

**Keywords:** biodiversity; biopesticides; conventional insecticides; crop farming; ecosystem health; environmental protection; insect ecology; natural enemies; pest control; sustainable agriculture
