The importance of monitoring the Ceutorhynchus pallidactylus female flight activity for the timing of insecticidal treatment

Abstract

(2006, 2007, 2008). It was less important and somewhat less complicated to establish the most suitable time for spraying in the case of the chlorpyrifos + cypermethrin combination in comparison with the pyrethroids applied separately. The effectiveness of the tested insecticides was markedly influenced by the time of spraying. The effects of the pyrethroids applied singly achieved results comparable to those of the chlorpyrifos + cypermethrin combination only at the optimal spraying time. The most suitable time for spraying varied from the point when the first females appeared in yellow water traps in somewhat higher quantities to the time when a substantial proportion of caught females was able to lay eggs.

Spatio-temporal Distributions and Associations of Cabbage Stem Weevil (Ceutorhynchus Pallidactylus Marsham, 1802) and Pollen Beetle (Brassicogethes Aeneus Fabricius, 1775) in winter oilseed rape

“…So, on the basis of this study it is not possible to confirm the previous results that females of C. pallidactylus enter the winter oilseed rape crops markedly later than males. On the other hand in this study the proportions of females were increasing in YWTs during the period of fly activity of the adults in the crop, in agreement with the findings of Seidenglanz et al (2009) and Johnen et al (2010). Klukowski (2006) also studied changes in within-field spatial distribution patterns of male and female C. pallidactylus in the course of crop colonisation.…”

“…He found that the males arrived before the females. This tendency was also documented by Seidenglanz et al (2009). However, in this study the first C. pallidactylus females appeared in the crop (more precisely in YWTs located in crops) at the same time as the males in 2013 and 2014.…”

“…As shown in many previous studies (Alford et al, 2003;Seidenglanz et al, 2009;Junk et al, 2012;Vaitelyté et al, 2013; and many others) the dates when migration of C. pallidactylus and B. aeneus adults in winter oilseed rape crops commences, peaks and ends can fluctuate very considerably from year to year depending on a variety of environmental (especially meteorological) factors. In Europe, different ways of timing insecticidal sprays against these pests are based on continual monitoring of some simple-to-measure meteorological factors (individually or in combination) (in detail in Junk et al, 2012).…”

Analysis of oilseed rape stem weevil chemical control using a damage rating scale

“…In order to evaluate the actual damage caused by larvae, an assessment using a six‐point damage rating scale was performed (Table ). For this purpose we used a modified scale described by Seidenglanz . Plants without damage and no recorded weevils were rated as zero.…”

“…For this purpose we used a modified scale described by Seidenglanz. 16 Plants without damage and no recorded weevils were rated as zero. Slightly damaged plants with tunnels in stems up to 10% of stem length were rated 1, plants with longer tunnels (11-25% of stem) and with low lodging probability were rated 2.…”