Biology and harmfulness of Brassica pod midge (Dasineura brassicae Winn.) in winter oilseed rape

The Brassica pod midge (Dasineura brassicae Winn.) is an important pest in oilseed rape (Brasica napus L.). It develops two generations per year and overwinters in the larval stage in cocoons in soil. Immigration of the first generation adults lasted from the beginning of April until the end of May. Larvae developed in pods from mid-April to mid-June, causing pod deformation and cracking, which resulted in premature falling out of seeds and yield reduction. Pod damage amounted to 11.6%. The emergence of the second generation adults was detected at the end of May and in the first ten days of June. D. brassicae was found to lay eggs in healthy pods and no correlation was found with the cabbage seed weevil, Ceutorhynchus assimilis Paykull.

Key pests and their parasitoids on spring and winter oilseed rape in Estonia

The pests and their hymenopterous parasitoids present in a spring and a winter oilseed rape crop in Estoniawere studied. Meligethes aeneus was themost abundant pest in both crops. Other crucifer-specialist pests included: Ceutorhynchus assimilis, C. pallidactylus, C. rapae, C. floralis, C. pleurostigma and Phyllotreta spp., but their abundance was low. Four species of parasitoids of M. aeneus larvae (Diospilus capito, Phradis morionellus, P. interstitialis and Tersilochus heterocerus) and threeof C. assimilis larvae (Mesopolobus morys, Stenomalina gracilis and Trichomalus perfectus) were also found.

Resistance of canola-quality cultivars of yellow mustard, Sinapis alba L., to the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham)

Oilseed Bassica is susceptible to attack by the cabbage seedpod weevil while commercial yellow mustard, Sinapis alba L., is resistant. The objective of this study was to determine if canola-quality S. alba would maintain its resistance traits. In laboratory choice and nochoice tests we found the number of eggs laid by the weevil to be low or non-existent in all S. alba genotypes. Key words: Ceutorhynchus obstrictus, Ceutorhynchus assimilis, Sinapis alba, plant resistance