Does intercropping patterns of potato and safflower affect the density of Leptinotarsa decemlineata (Say), predators, and the yield of crops?

Abstract

The impact of three intercrop patterns of potato (P), Solanum tuberosumL., and safflower (S), Carthamus tinctoriusL.: 4P:2S, 4P:4S, and 4P:8S (row ratios) along with single crops were examined on densities of the Colorado potato beetle (CPB),Leptinotarsa decemlineata(Say), biodiversity of predators, and yield profits over the growing season of potatoes in a randomized complete block design in 2019 and 2020 in Iran. The significant reduction in the densities of CPB (adults, eggs, and larvae) was seen in intercrops compared with single potato in either year. Accordingly, the damage index was decreased in intercrops than in single potato. Furthermore, intercrops resulted in an enhancement in the abundance of most predatory species of CPB, the Shannon diversity index (H΄), and the Pielou's evenness index (J'), especially in 4P:4S and 4P:8S than single potato. The values of R2 between the densities of CPB and the main predators were low (0.01 ≤ R2 ≤ 0.19) in June, whereas R2 values were significantly enhanced in July (0.13 ≤ R2 ≤ 0.71) and August (0.46 ≤ R2 ≤ 0.97). All intercrops delivered extra yield benefit compared with the single crops (LER ≥ 1.20 in 2019 and ≥ 1.18 in 2020). Our results disclosed that all intercrops, especially 4P:4S and 4P:8S could exercise in the controlling ofL. decemlineatain potato fields.