The effects of two pyrethroid (lambda-cyhalothrin, alpha-cypermethrin) and two neonicotinoid (acetamiprid, thiacloprid) insecticides on B. pisorum L. eggs were compared under field conditions in the Czech Republic in 2005–2007. The main objective of the study was to find out what real effects can be expected from the available insecticides registered in Europe when applied at the time of the first egg occurrence on lower pods. In general, the rates of Bruchus pisorum egg (+ first instar larvae) survival were significantly lower with all the insecticides compared in the study, in each of the three years (2005, 2006, 2007). The tested insecticides showed some ovicidal effects and also some larvicidal effects. The tested pyrethroids (lambda-cyhalothrin, alpha-cypermethrin) showed somewhat higher effectiveness in comparison with the neonicotinoids (acetamiprid, thiacloprid). Alpha-cypermethrin was the most effective in all three years. In 2006 and in 2007 this insecticide significantly reduced the rates of egg survival in comparison with acetamiprid. In contrast, acetamiprid was the least effective insecticide in each of the three years.

Seidenglanz M., Poslušná J., Rotrekl J., Kolařík P., Hrudová E., Tóth P., Havel J., Bernardová M.

Seidenglanz M., Poslušná J., Rotrekl J., Kolařík P., Hrudová E., Tóth P., Havel J., Spitzer T., Bernardová M.

Seidenglanz M., Poslušná J., Kolařík P., Rotrekl J., Hrudová E., Tóth P., Havel J., Plachká E., Táncik J., Hudec K. (2017)

The clover seed weevils, Apion trifolii and Protapion apricans, members of the genus Apion, are responsible for causing serious economic damage in clover. In 2010-2012, the effectiveness of some insecticides against clover seed weevils in the genus Apion were tested in red clover stands. The efficacy of different products was evaluated on the basis of analyses of specimens trapped in the herb layer of red clover using a sweep net and red clover heads sampled in individual plots. Over the course of these trials, the applications of the products tested resulted in a marked reduction in their numbers (particularly of adults and, to a lesser extent, also of larvae). The highest efficacy was observed with Biscaya 240 (A.I. thiacloprid) and Mospilan 20 SP (A.I. acetamiprid). Results obtained in this study corroborated the low efficacy of the insecticide Karate Zeon Technology 5 CS against seed weevils of the genus Apion.

Due to the length of egg-laying period (> 80 days), two applications of insecticides against cabbage stem weevil (Ceutorhynchus pallidactylus Marsh.) are currently needed. However, resistance of pollen beetle (Brassicogethes aeneus F.) to pyrethroids complicates the choice of suitable insecticide for the second application. The active ingredients cypermethrin, etofenprox, pymetrozine, indoxacarb and chlorpyrifos-ethyl applied as second spring applications to winter oilseed rape crops were assessed under field conditions from 2016 to 2018 to ascertain how they could reinforce the effects of the first spring application (beta-cyfluthrin) on cabbage stem weevil. Chlorpyrifos-ethyl and etofenprox strengthened the effects of the first spring spray on cabbage stem weevil markedly more than cypermethrin. Pymetrozine and indoxacarb, effective on resistant populations of pollen beetles, showed the lowest contribution to increase the effects. Indoxacarb showed a low effect on C. pallidactylus in laboratory tests too. The impacts of the bans on active ingredients chlorpyrifos-ethyl and pymetrozine are discussed.

The effectiveness of selected insecticides against capsule weevils (Neoglocianus maculaalba) and capsule midges (Dasineura papaveris), which are the main pests of breadseed poppy, was verified in a small-plot field experiment in 2015–2017. The effect of foliar application was evaluated according to boreholes on capsule surfaces caused by the feeding of capsule weevil adults and larvae numbers in capsules collected approximately 4 weeks after application. Biological efficacy of the tested biological formulations Spintor (active ingredient spinosad 240 g/l) in dosage 0.4 l/ha and NeemAzal T/S (active ingredient azadirachtin A 10.6 g/l) in dosage 3 l/ha against N. maculaalba larvae in individual years of monitoring ranged from 46.4% to 77.7% and from 67.7% to 82.9%, respectively. The effect of the formulation Prev B2 (boron ethanolamine corresponding to 2.1% of water-soluble boron) in 0.3% dosage was in the range of 59.5–81.9%. Their efficacy did not differ significantly compared to the registered chemical standards Biscaya 240 OD (active ingredient thiacloprid 240 g/l) and Decis Mega (active ingredient deltamethrin 50 g/l). Therefore, these biological insecticides are potentially useful for the effective control of N. maculaalba and D. papaveris population densities and reduction of damage they cause to breadseed poppy.

Oilseed rape is frequently damaged by insect pests. Much attention is paid to the protection of oilseed rape against Brassicogethes aeneus (Coleoptera: Nitidulidae), which is one of the most significant pests of spring and winter oilseed rape. The presence of different pollen beetle species was monitored in the Czech Republic in the years 2011–2013. A minimum of 500 individuals were captured at each site. Morphometric characteristics and the morphology of male and/or female genitalia were used to determine species. B. aeneus, B. subaeneus, B. viridescens and B. coracinus were most abundant. Other species presented in oilseed rape were B. coeruleovirens, B. czwalinai, B. matronalis, B. anthracinus, Boragogethes symphyti, Cychramus luteus, Fabogethes nigrescens, Genistogethes carinulatus, Meligethes atratus, Sagitogethes maurus, and Lamiogethes atramentarius. Our main conclusion is that the reason for the presence of the pollen beetle species associated with their development into non-cruciferous plants in oilseeds is the sufficiency of pollen as food for beetles. In addition, they may occur here incidentally, as they can be transported relatively long distances by air. Accompanying species of pollen beetles probably also have a positive effect on abundance reduction in species considered to be harmful as they are hosts to parasitoids of the oilseed rape pest.