Effects of soil biofumigation on non-target springtails (Collembola) and earthworms (Opisthopora)

Soil health is supported by diverse communities of organisms, including springtails and earthworms, facilitating essential processes such as nutrient cycling, organic matter decomposition, and soil structure maintenance. Cultural control methods promoted through Integrated Pest Management (IPM) are often assumed to be environmentally friendly, and their potential effects on soil health have received limited attention. Biofumigation, a cultural tactic, utilizes cruciferous plants like Brassica juncea (Brassicales: Brassicaceae), or their byproducts, to control soil-borne pests, yet their impacts on non-target organisms remain understudied. In this greenhouse study, we evaluated the impact of soil biofumigation with brown mustard seed meal (BMSM) on the springtail Folsomia candida (Entomobryomorpha: Isotomidae) and the earthworm Eisenia fetida (Opisthopora: Lumbricidae). An 85% reduction in springtail populations was recorded within 1 h of BMSM application. However, the springtail population recovered and surpassed the number of springtails in untreated media after 26 days. Earthworms preferred untreated media over BMSM-treated media immediately after incorporation. However, earthworms reared in the biofumigated media had higher body weight and produced more viable cocoons compared to those reared in untreated media. The negative effects of biofumigation on springtails and the deterrence of earthworms appeared to be short-lived and may later contribute to their reproductive fitness.