The cultural control of some important pests in cabbage (Brassica oleracea var. capitata L.) and onion (Allium cepa L.) using companion plants

Cabbage (Brassica oleracea var. capitata L.) and onion (Allium cepa L.) are two of the most important vegetables in the world, and many insect pests are a problem in their production. Currently, especially in Europe, restrictions on the use of pesticides are increasingly being encouraged, so the need to find and use alternative methods is increasingly urgent. Cultural control of insect pests using companion plants, including cover crops, intercrops, and trap crops, has been proven to help manage these insect pests. Companion plants reduce plant insects primarily by disrupting host-seeking activity, disrupting oviposition, increasing the plant's natural enemies, or luring the pests to alternative food sources. This review outlines successful examples from around the world of the use of companion crops in controlling insect pests, focusing on the main pests of cabbage and onions in Europe. Details regarding the working mechanism of each of the three companion plants are discussed further in this article. We concluded that these companion plant tree forms effectively reduce the number of generalist and specialist plant pests attacking cabbage and onion.