Attractiveness of Cabbage Maggot (Diptera: Anthomyiidae) to Entomopathogenic Steinernematid Nematodes

The cabbage maggot, Delia radicum (L.), an important pest of crucifer crops, is a good candidate for control by nematodes, because different parts of its life-cycle occur in the soil. To understand the interaction between nematodes and both eggs and larvae of the cabbage maggot, we examined their attractiveness to the Steinemena carpocapsae All strain in muck soil. We also quantified the ability of some steinernematids to intercept migrant 1st instars before root penetration and to follow larvae into root tunnels in a seminatural environment (soil, plant, host). S. carpocapsae All strain was not attracted by cabbage maggot eggs, whereas they oriented toward newly hatched cabbage maggot larvae. S. carpocapsae All and UK (Biosys 252) strains killed a significant proportion of migrant cabbage maggot larvae before they could penetrate into radish roots. Although most steinernematids tested followed larvae into the radish roots, only S. feltiae (= bibionis) induced significant infection. Our results indicate that steinernematids have the ability to intercept cabbage maggot 1st in stars and to follow and infect developing cabbage maggot larvae in roots. However, studies must be undertaken to select the best interceptor and tunnel follower nematode species to control the cabbage maggot, as well as to determine the best timing of nematode application.