Readme file generated by Ola Lundin on 2025-04-11 for the dataset with the title:
Data for: Effects of insecticide treatment against blue stem weevil (Ceutorhynchus sulcicollis) and cabbage stem weevil (C. pallidactylus) on crop injury and yield in winter oilseed rape (Brassica napus) 

File information:

Stem injury was assessed twice, once mid-May (May 17 in 2023, May 14-15 in 2024) at crop stage BBCH (Biologische Bundesanstalt für Land- und Forstwirtschaft,, Bundessortenamt und CHemishe Industrie) 59-61 (early flowering), and once in June (June 11-12 in 2003, June 28 in 2024, BBCH 69-75; pod development). The first assessment was close to the estimated onset of egg-laying by C. pallidactylus when the spring insecticide application were conducted. Injury assessed at this time point should therefore mainly be attributed to C. sulcicollis and no effects of the insecticide treatments conducted in spring on stem injury were expected at this time point. The second assessment reflects combined stem injury from both C. sulcicollis and C. pallidactylus. 
At each injury assessment, we dug up 20 randomly selected oilseed rape plants per plot. Stems were cut open and the length of the stem with insect-caused injuries was measured. We also classified the injury in classes from 1 to 4, which represented plants with no (injury (rating 1), light (2: slight tunnelling, most of the stem intact, a few larvae present at most), medium (3: severe discoloration with several larvae, but vascular tissue still intact) and severe injury (4: severe injury reaching vascular tissue), respectively. Due to a degree of subjectivity involved in the injury rating, assessors collectively inspected plants prior to the assessment occasions to calibrate the ratings among assessors, and the same assessor always rated all plants from a complete block of treatments for stem injury. 
File: "WeevilInjury.csv"
Variables: 8: site_ID, year, block, treatment, assessment, injury_rating, injury_length, injury_length_prop
Data rows: 184


We assessed injury by pollen beetle and brassica pod midge in late June or early July (June 28 in 2023, July 1-3 2024, BBCH 75) when the crop was turning in colour from green to yellow. We selected ten plants from each plot. In each plant, we selected three shoots; one in the lower, middle and upper part of the plant, respectively. On each shoot, we counted the number of podless stalks caused by pollen beetles, the number of distorted and discoloured pods injured by brassica pod midge as well as the number of intact pods. Select injured pods were also opened to confirm the presence of brassica pod midge larvae. We calculated the proportion of pods injured by pollen beetles as the number of podless stalks divided by the sum of all three categories (podless stalks, injured by brassica pod midge or intact). The proportion of pods injured by brassica pod midge was calculated as injured pods divided by the sum of injured and intact pods (i.e. not including podless stalks, as they do not provide any pods for brassica pod midge).
File: "PodInjury.csv"
Variables 6: site_ID, year, block, treatment, ProportionPollenBeetle, ProportionMidge
Data rows: 92


We monitored the emergence of the new generation of stem mining weevils from June 19 to July 24 in 2023 and from June 17-19 to July 22-24 in 2024 with emergence traps. We placed one emergence trap in each plot. The emergence traps consisted of a metal ring (diameter 35 cm, height 30 cm) that was buried approximately 10 cm into the soil. The emergence traps covering 0.096?m2 each were set up with one or two oilseed rape plants inside that were cut at the base. The rings were covered with a fine mesh that was secured with a strap. We placed one yellow sticky trap horizontally on wooden skewers inside each emergence trap. Yellow sticky traps were replaced weekly for five weeks until the emergence traps were removed due to harvest of the fields. Eleven weekly trap catches (2.4%) were lost due to wildlife damage and lodging of the crop. Beetle emergence was calculated as emerged individuals per day across all available samples per plot.
File: ”Emergence.csv”
Variables: 10: site_ID, year, block, plot, treatment, sulcicollis, pallidactylus, days, sulcicollis_per_d, pallidactylus_per_d
92 data rows


A 9 m by 2 m area in the centre of each harvest plot was harvested with an experimental thresher near the time of commercial harvest of the field. A sample of seeds from each harvested plot was rinsed and analysed for water and oil content using near-infrared transmittance (AgriLab, Uppsala, Sweden). All yields were standardised to kg per ha-1 of rinsed seed with 9% water content. 
File: "Yield.csv"
Variables 7: site_ID, year, block, treatment, yield, oilcontent, oilcontent_prop
72 data rows


Explanation of variables:
site_ID: site identifier. There are five experimental sites in each file. The site identifier consists of the nearest city and the year the experiment was harvested. 
year: year experiment was harvested (2023 or 2024).
block: block (1-4) within each field experiment.
plot: unique plot number within each experiment. The first number in the plot identifier is the same as the block number. 
treatment: (experimental treatment). (A): insecticide treatment in autumn (Nexide CS;, gamma-cyhalothrin, 3.6 g ha-1) against C. sulcicollis, (B) insecticide treatment in spring (Mavrik; tau-fluvalinate, 48 g ha-1) against C. pallidactylus, (C) insecticide treatment in spring (Nexide CS;, gamma-cyhalothrin, 3.6 g ha-1) against C. pallidactylus (D) insecticide treatment both in autumn and spring (Nexide CS;, gamma-cyhalothrin, 3.6 g ha-1 and Mavrik; tau-fluvalinate, 48 g ha-1) against both species and (E) untreated control.
assessment: time point for the assessment of stem injury (early or late).
injury_rating: rating of injury (1-4). We classified the injury in classes from 1 to 4, which represented plants with no (injury (rating 1), light (2: slight tunnelling, most of the stem intact, a few larvae present at most), medium (3: severe discoloration with several larvae, but vascular tissue still intact) and severe injury (4: severe injury reaching vascular tissue), respectively.
injury_length: length of stem injury in cm.
injury_length_prop: length of injury relative to the length of the main shoot (proportion). 
ProportionPollenBeetle: We calculated the proportion of pods injured by pollen beetles as the number of podless stalks divided by the sum of all three categories (podless stalks, injured by brassica pod midge or intact).
ProportionMidge: The proportion of pods injured by brassica pod midge was calculated as injured pods divided by the sum of injured and intact pods (i.e. not including podless stalks, as they do not provide any pods for brassica pod midge).
sulcicollis: the number of Ceutorhynchus sulcicollis in emergence traps.
pallidactylus: the number of Ceutorhynchus pallidactylus in emergence traps.
days: the number of active traps multiplied by the number of days.
sulcicollis_per_d: sulcicollis divided by days.
pallidactylus_per_d: pallidactylus divided by days.
yield: yield of oilseed rape seeds in kg per ha.
oilcontent: oil content in oilseed rape seeds (%).
oilcontent_prop: oilcontent expressed as a proportion.