Effect of Intercropping White Cabbage with French Marigold (Tagetes Patula Nana) and Pot Marigold (Calendula Officinalis) on Diamondback Moth (Plutella Xylostella L.) Population Density and it's Parasitoid Complex

The impact of intercropping white cabbage (‘Bently F₁’) with French Marigold Tagetes patula nana ‘Kolombina’ and Pot Marigold Calendula officinalis ‘Promyk’ on the occurrence of diamondback moth (DBM) (Plutella xylostella L.) and its parasitoid complex was estimated in years 2003-2005. The number of DBM larvae and pupae was significantly lower on plots where cabbage was intercropped compared with the control variant (homogenous crop). The combination with Pot Marigold turned out to be the best in this respect. The DBM larvae parasitization level varied from year to year and its percentage oscillated from 65 to 88%. Eight beneficial insect species belonging to families: Ichneumonidae (4 species), Braconidae (2 species), Pteromalidae (1 species) and Eulophidae (1 species) emerged from collected DBM pupae. Diadegma fenestralis Holmgr. was the most abundant species among all Plutella parasitoids every year of observations as it constitued 65% of all of the reared wasps. No significant differences were determined between the level of parasitization in relation to the type of cultivation.