The root-knot nematode Meloidogyne incognita is an emerging problem in pepper crops grown in greenhouses in Campo de Cartagena (Murcia), caused by the banning of methyl bromide. Greenhouse-grown brassica has interest as an excellent rotation crop and as green amendment during the process of biosolarization. Since some species of brassica are multipliers of M. incognita, the balance between nematode multiplication during brassica culture and the effect on population reduction during biosolarization should be evaluated. The cultivars 'Boss', 'Carwoodi', 'Eexta' and 'Karakter' (Raphanus sativus), 'Scala' (Brassica juncea) and 'Ludique' (Sinapis alba) were evaluated in a greenhouse naturally contaminated with M. incognita during two consecutive years. The J2 population, the gall index, the number of egg masses per plant, and the percentage of affected plants of brassica and pepper were measured during the cultivation period after biosolarization. 'Karakter' and 'Eexta' were considered as poorly hosts to M. incognita and 'Carwoodi' and 'Boss' as non-hosts, since they reduced the number of egg masses on a 93-99% compared to cultivars of Brassica juncea and Sinapis alba and weeds of Amaranthus blitoides. The biosolarización with green brassicas reduced the population of juveniles. Non multiplier effects of brassica and biosolarization reduced the galls in pepper roots during the first months of growing, resulting in a better yield compared to the control.