DOI: 10.5061/dryad.dv41ns273
title: Data from: Impact of planting and harvest dates on yam infestation by white grubs

description: The white grub, Diaprepes abbreviates L. (Coleoptera: Curculionidae), is a
 significant pest of yam tubers and the second cause of tuber rot in Haiti.
 Larval feeding inflicts severe damage to tubers, leading to notable losses
 due to decreased tuber quality, reduced marketability, and increased
 susceptibility to secondary parasites and pathogens. This study examined
 the influence of planting and harvesting dates on the vulnerability of yam
 tubers to white grub infestation and the resulting tuber quality across 24
 farmers’ fields. At harvest, we assessed the level of tuber infestation,
 white grub density, and the tuber quality index. The results indicated
 that 85% of grub populations were found in fields planted on the
 traditional date. In addition, 69.5% of tuber damage occurred in
 early-planted fields with fewer tubers damaged (30%) when harvested early.
 In contrast, in fields planted 30 days after the traditional date, the
 harvest date did not affect tuber infestation and damage by the pest.
 Overall, both planting and harvest dates impacted the quality grade of yam
 tubers. Delayed planting by 30 days and early harvesting (34th -38th week
 after planting) improved the marketability of yams. These findings
 highlight the importance of optimizing planting and harvest schedules to
 better manage white grub infestation and enhance the marketability of yam
 tubers.
description: We studied 24 neighboring farmers' fields, split into two
 main fields with planting date as the main field factor and harvest date
 as the subfield factor. The main factor had two levels: planting on
 traditional date (DAP 0), and planting 30 days after the traditional date
 (DAP 30), with 12 fields at each level. The traditional date for planting
 yams corresponds to the yam planting peak which occurs in April, when most
 farmers set up their plots. The second planting date (DAP 30) was chosen
 based on information provided by farmers reporting that plots not planted
 in April are planted in late May or early June during a second planting
 period. The second factor, harvest date, consisted of three levels:
 harvesting at the 34<sup>th</sup>,
 38<sup>th</sup>, and 42<sup>nd</sup> week after
 planting, with four replications of each level.  Data
 were recorded at harvest time by randomly selecting five planting mounds
 per treatment field, i.e., five planting moundings per harvest date. Grub
 density and hole density per tuber were assessed by counting the number of
 grubs in each planting hole and the number of holes in each tuber. Hole
 size in yam tubers, including diameter and depth, was measured using a
 palmer and a ruler, respectively. Yam harvest density was determined by
 counting the number of tubers harvested in each planting hole. Tuber
 weight was measured with a scale, BAICO (PRI PA’W, Jérémie, Haiti), and
 the tuber quality index was calculated by dividing the number of undamaged
 tubers by the total number of tubers harvested per planting
 hole.
description: # Data from: Impact of planting and harvest dates on yam infestation by
 white grubs
 [https://doi.org/10.5061/dryad.dv41ns273](https://doi.org/10.5061/dryad.dv41ns273) ## Description of the data and file structure We setup a trial on 24 farmers' fields, split into two main fields with planting date as the main field factor and harvest date as the subfield factor. The main factor had two levels: planting on traditional date (DAP 0), and planting 30 days after the traditional date (DAP 30), with 12 fields at each level. The second factor, harvest date, consisted of three levels: harvesting at the 34th (Week 34), 38th (Week 38), and 42nd (Week 42) week after planting, with four replications of each level. Data were recorded at harvest time by randomly selecting five planting mounds per treatment field, i.e., five planting moundings per harvest date. Grub density and hole density per tuber were assessed by counting the number of grubs in each planting hole and the number of holes in each tuber. Hole size in yam tubers, including diameter and depth, was measured using a palmer and a ruler, respectively. Yam harvest density was determined by counting the number of tubers harvested in each planting hole. Tuber weight was measured with a scale, and the tuber quality index was calculated by dividing the number of undamaged tubers by the total number of tubers harvested per planting hole. ### Files and variables #### File: White\_grub\_dataset.xls **Description:**  ##### Variables * Total harvested tuber * Tuber weight (lb) * Total undamaged tuber * Total damaged tuber by white grub * Total hole by white grub * Hole Depth (mm) * Hole diameter (mm) * Total white grub * Marketable yield * Unmarketable yield * Total yield (Marketable and unmarketable yield) * % of damaged tuber * % of undamaged tuber ## Code/software RStudio software (version: 2023.09.1) was used for data viewing and analysis. This is a free software with multiple packages included that allow to perform multiple analysis. I used mainly four packages such as, ggplot2, dplyr, emmeans, agridat, multcomp for processing my data.