Evaluation of trap cropping for management of root-knot nematode on annual crops

B.B. Westerdahl
In trap cropping, a host is planted and larvae of a sedentary parasitic nematode such as root-knot are induced to enter and establish a feeding site. Once this has occurred, and the female begins to mature, she is unable to leave the root. The plants are then destroyed before egg-laying by nematodes is initiated, trapping nematodes within the root. Two field trials were conducted in subsequent years in a field with an established population of root-knot nematode (Meloidogyne javanica). Each trial consisted of 20 treatments, with five replicates of each treatment in a randomized complete block design. Treatments were either carrots planted as a trap crop, wet fallow as a trap crop (irrigation to germinate weeds), dry fallow (untreated control), or standard chemical (1,3-Dichloropropene). Eight treatments were identical in the two trials. The other treatments differed by date of crop termination. In Trial 1, trap crops were terminated at either three or four-weeks following planting. In Trial 2, termination was at either two or three weeks following planting. Following termination of the trap crops, all treatments were planted to carrots. Some of the treatments were treated at planting with a biological nematicide (DiTera). Compared to the untreated control, a number of the other treatments demonstrated a greater percentage of marketable carrots and a reduction in the level of root-knot nematodes at harvest. These results indicate that either planting a trap crop or that a pre-irrigation to germinate weeds could provide a degree of nematode control. A trap crop can be any root-knot nematode susceptible seed. Carrots were selected based on results of previous trials comparing potential trap crops. Carrots were also used as the final “commercial” demonstration crop because they are a sensitive root-knot nematode bioindicator crop. Results from carrots could be extended to other root-knot sensitive crops.
Westerdahl, B.B. (2020). Evaluation of trap cropping for management of root-knot nematode on annual crops. Acta Hortic. 1270, 141-146
DOI: 10.17660/ActaHortic.2020.1270.15
root-knot nematode, Meloidogyne sp., trap crop, carrots, Daucus carota subsp. sativus

Acta Horticulturae