Control by seed dressing of leaf weevils of the genus Sitona (Col.: Curculionidae) feeding on sprouting alfalfa

Abstract

Rotrekl J., Cejtchaml J. (2008): Control by seed dressing of leaf weevils of the genus Sitona (Col.: Curculionidae) feeding on sprouting alfalfa. Plant Protect. Sci., 44: 61-67.In tests with artificial infestation of alfalfa by leaf weevils in the greenhouse and also in small-plot trials with natural infestation of sprouting alfalfa it was found that without protection alfalfa is seriously damaged by leaf weevil feeding. After evaluation of the feeding damage by weevils, the damage to plants in the untreated plot was classed as 3 rd , 4 th and 5 th degree on a five-level scale. Plant growth was seriously restricted and in warm and dry weather plants may die. The results demonstrate that in both kinds of trials the pre-sowing treatment of alfalfa seed significantly reduces the feeding of leaf weevils on sprouting alfalfa. No negative effects of insecticidal seed dressing on germination energy and germination were observed. On the basis of the three-year trials, the dressing insecticides Cruiser 350 FS (active ingredient thiamethoxan) and Elado 480 FS (active ingredients beta-cyfluthrin and clothianidin), both at a dose of 20 l/t, can be recommended as an effective method to protect alfalfa against leaf weevils.

Weevil (Coleoptera: Curculionidae) assemblages in the fields of narrow-leafed lupin sown as pure stand and intercropped with spring triticale

“…Andow (1991) shows that the density of insect pest in polyculture system was lower in 52%, equal in 13% and variable in 20% of the studied cases in comparison to monocultures. Adults representing Sitona or Charagmus genus are known as the leaf weevils causing serious damage to different leguminous crops, while their larvae can harm the root system of the plants (Petrukha, 1970;Rotrekl, Cejtchaml, 2008;Toshova et al, 2009). Adults feed mainly on the same host plant as the larvae (Velasquez de Castro et al, 2007).…”

Pea leaf weevil, Sitona lineatus (L.) (Coleoptera: Curculionidae), adult feeding preference and larval development on pulse crop varieties in Montana

“…Ten plants were selected randomly from each plot and assigned to one of six categories: 0 (notches not observed), 1 (1-5 notches observed on plant), 2 (>5 notches observed per plant but not on most leaves), 3 (>12 notches observed on portions of most leaves), 4 (notches completely surround most leaves) and 5 (feeding results in defoliation in addition to notches). 48,54,55 Adult activity was monitored using pitfall traps baited with the aggregation pheromone. Moth unitraps baited with 4-methyl-3,-5-heptanedione septum lures (RD 5.481, P575-Lure; ChemTica International, Heredia, Costa Rica) were buried with the trap entrance at soil level.…”

“…1(E) and Table S2). Ten plants were selected randomly from each plot and assigned to one of six categories: 0 (notches not observed), 1 (1–5 notches observed on plant), 2 (>5 notches observed per plant but not on most leaves), 3 (>12 notches observed on portions of most leaves), 4 (notches completely surround most leaves) and 5 (feeding results in defoliation in addition to notches) 48,54,55 …”

Effect of temperature, population density, and sex on feeding damage caused by adult pea leaf weevil (Coleoptera: Curculionidae)

“…Sitona lineatus populations need to be managed to prevent yield loss, but they are difficult to control using chemical insecticides. Because S. lineatus larvae are concealed inside root nodules, adults must be killed before they lay eggs in the spring, which requires application of costly systemic insecticides (Rotrekl and Cejtchaml 2008;Vankosky et al 2011b) or timely intervention using foliar insecticides (Seidenglanz et al 2010), which are largely ineffective (e.g., cyhalothrin-lambda only slightly reduces the foliar damage caused by adult weevils; Seidenglanz et al 2010).…”