Arthropod-Plant Interactions (2018) 12, 799-809
Meike Brandes, Udo Heimbach and Bernd Ulber (2018)
Effects of insecticide application on parasitism rates of pollen beetle larvae (Brassicogethes aeneus (Fabricius)) by tersilochine parasitoids
Arthropod-Plant Interactions 12 (6), 799-809
Abstract: Larval parasitoids can substantially reduce the population density of the pollen beetle [Brassicogethes aeneus (Fabricius), syn. Meligethes aeneus (Fabricius)]. The most abundant tersilochine parasitoids of pollen beetle are Tersilochus heterocerus, Phradis interstitialis and P. morionellus. The main activity of these parasitoids was observed in the period shortly before flowering to full flowering of oilseed rape. Insecticide applications during this period may have negative effects on parasitoids. In the present study, the effects of the insecticides Biscaya (a.i. thiacloprid), Mavrik (a.i. tau-fluvalinate) and Karate Zeon (a.i. lambda-cyhalothrin) applied during the bud or flowering stage of winter oilseed rape on parasitization of pollen beetle larvae by T. heterocerus were studied in 12 field trials at different locations in Germany in 2013–2015. The effects on parasitism by Phradis spp. were assessed in 2015. Parasitism of pollen beetle larvae by T. heterocerus was found in all field trials in all experimental years, but in most trials not before full flowering. Maximum percentage of parasitized larvae at different locations ranged between 3.4 and 16.8% in 2013, 8.3 and 22.4% in 2014 and from 11.1 to 29.1% in 2015. Levels of parasitism were not significantly different between the untreated control and insecticide treatments within each location. In contrast to T. heterocerus, Phradis spp. was not detected at all locations and not before flowering declining. In field trials at Lucklum and Puch, the maximum level of parasitism by Phradis spp. was 9.4 and 18.3%, respectively. No significant effect of insecticide application on parasitism by Phradis spp. was observed between the treatments. The results of this study showed that the insecticides used in the field trials did not affect parasitization of pollen beetle larvae by T. heterocerus and Phradis spp., regardless whether applied at the bud stage, at the beginning of flowering or full flowering.
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Link to article at publishers website
Database assignments for author(s): Bernd Ulber
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance to pesticides
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Brassicogethes aeneus | Rape/canola (Brassica napus) | Germany | ||
| Phradis morionellus (parasitoid) | Brassicogethes aeneus | |||
| Tersilochus heterocerus (parasitoid) | Brassicogethes aeneus | Rape/canola (Brassica napus) | Germany | |
| Phradis interstitialis (parasitoid) | Brassicogethes aeneus |
