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

Abstract

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.

Pollen Beetles in Oilseed Rape Fields: Spectrum and Distribution in Czech Republic during 2011–2013

“…B. aeneus and B. viridescens are among the most common species in the UK [3,9], both these species are also considered to be important in Sweden [65]. In Estonia, B. viridescens is very common in oilseed rape, more so in winter oilseed rape [66]. As stated by Finch et al [67], both species mentioned above can also damage cauliflower and broccoli, reducing their market value.…”

Blue stem weevil ( Ceutorhynchus sulcicollis ) – a potential threat to oilseed rape production

“…Ceutorhynchus sulcicollis shows similar behaviour to its intragenus relative Ceutorhynchus picitarsis Gyllenhal, which also undergoes summer aestivation until September, and lays eggs through autumn and winter (Barari et al 2005). In Estonia, Veromann et al (2006a) had detected only ten C. sulcicollis specimens in 2005 (using yellow water traps) on winter oilseed rape and zero in their previous studies in 2002-2003 in winter and spring oilseed rape (Veromann et al 2006b(Veromann et al , 2006c. However, Grantina (2012) indicated that the abundance of C. sulcicollis in Latvia can differ 11.2-fold between years, and that under certain conditions abundance may increase.…”

Pollen beetle offspring is more parasitized under moderate nitrogen fertilization of oilseed rape due to more attractive volatile signal

“…syn. Meligethes aeneus Fab) is the most numerous pest of oilseed rape in Northern countries like Estonia 35 . Oilseed rape is most susceptible to pollen beetles during the bud stage (BBCH 51–59) 36 , 37 when adults destroy flower buds to feed on the pollen 38 , 39 .…”

“…Parasitoids lay eggs into B. aeneus eggs and/or larvae and the emerging parasitoid larvae feed and develop in the host, eventually killing it 47 . The effectiveness of parasitoids has been demonstrated in natural conditions by many field studies 35 , 48 – 53 as well as in controlled environment 25 .…”