Crambe Cake to Meloidogyne javanica Control in Lettuce

Crambe is an oilseed, which pressing for oil extraction results in the waste called crambe cake. The aforementioned waste may present potential to control nematodes, since it derives from brassica species. The aim of the current study is to assess the best crambe cake application to control Meloidogyne javanica in lettuce plants. Five experiments were carried out in a greenhouse by adopting different crambe cake application procedures; each experiment comprised five treatments (0 (control), 5; 10; 15; 20 g crambe cake per 1 L soil). Lettuce seedlings were cultivated in soil treated with crambe cake, and inoculated with 5,000 nematode eggs and occasional juveniles (J2). Nematological and vegetative parameters were assessed 45 days after inoculation. Nematode reduction was observed in the experiment that applied doses close to 15 g crambe cake to the soil surface; nematode control recorded 83 and 68% for eggs and J2 total and per root gram, respectively. The same parameters showed up to 82 and 93% reduction when the cake was incorporated to the first 8 cm deep into the soil. The number of eggs and J2 per root system reduced by 93% when the cake was incorporated to the total soil volume. Overall, the crambe cake did not increase plant development; in some cases, phytotoxicity was observed at the highest doses.