DOI: 10.5061/dryad.4j0zpc8jd
title: The effects of water-stress, temperature, and plant traits on the outbreak potential of a specialist and generalist spider mite species (Acari: Tetranychidae)

description: The host-generalist two-spotted spider mite [Tetranychus urticae (Acari:
 Tetranychidae); TSM] and host-specialist Banks grass mite [Oligonychus
 pratensis (Acari: Tetranychidae); BGM] are common pests of corn (Zea mays
 L.) in the arid western United States. Climate warming and decreased
 precipitation may promote conditions favored by these spider mites.
 However, rapid evolution of spider mite resistance to commercially
 available acaricides is driving the need for alternative solutions for
 managing outbreaks. Planting of drought-tolerant corn hybrids has been
 proposed to be a dual-purpose strategy for mitigating water deficits for
 irrigation and reducing leaf conditions favorable for BGM outbreaks.
 However, understanding of the mechanisms responsible for reducing the BGM
 in the field is lacking, and determining whether outbreaks of the TSM can
 also be averted using drought-tolerant corn is a pressing concern. We
 conducted a two-year field study testing a drought-tolerant corn hybrid
 and an analogous drought-susceptible hybrid under water-stress with
 artificially-infested spider mite populations. Drought-tolerant corn had
 larger stem diameter, more massive cobs, and greater leaf water mass
 compared to the drought-susceptible corn under water stress. We also found
 that the BGM populations were reduced on drought-tolerant plants under
 water-stress, as expected, but we found an opposite trend in the TSM.
 Lastly, water-stressed leaves were warmer, transpired less, and had higher
 carbon concentration, which contributed to larger investment in eggs and
 growth in the BGM. We anticipate that further evaluation of irrigation and
 crop drought-tolerance in management of agriculture systems for multiple
 pest species will be increasingly impactful in arid regions.
description: # The effects of water-stress, temperature, and plant traits on the
 outbreak potential of a specialist and generalist spider mite species
 (Acari: Tetranychidae) \[Access this dataset on Dryad\]\(Dataset DOI:
 10\.5061/dryad\.4j0zpc8jd\) Give a brief summary of dataset contents,
 contextualized in experimental procedures and results. Dataset contents
 include supporting data of leaf temperature, leaf nutrients, spider mite
 and egg densities, spider mite and egg morphometrics, plant (corn) field
 measurements, and soil moisture and nutrient measurements. Data are
 generally separated between the two sampling seasons, 2020 and 2021. 2020
 experimental treatments included levels of irrigation, corn drought
 tolerance, and spider mites introduced. In 2021, experimental treatments
 focused on irrigation and levels of drought tolerance. The experiment was
 conducted at Greenville Agricultural Research Station and Utah State
 University in Northern Utah, USA. ## Description of the data and file
 structure Spider mite density data (**MiteAndEgg
 Density\_Dryad\_October2023**) is structured with ID and treatment
 columns, followed by sample counts of eggs and motiles (mites) from
 laboratory counts using microscope. The counts were then divided by (leaf)
 Area to achieve Density (in units mites cm-2). Spider mite motile (adult
 female) and egg data (**Morphometrics\_Dryad\_October2023**) is structured
 with ID and treatment columns, followed by measurements of different mites
 or eggs from a treatment (replicates 1 to 17 in units mm). Final sampling
 period corn data (**Plant Field Measurements\_Dryad\_October2023**) ID and
 treatment columns, followed by sampling of the corn responses. There were
 two sample replicates of different plants taken with a leaf porometer
 (Conductance in units mmol m-2s-1 and Temperature in units Celsius
 responses) and leaf pressure chamber (Potential in units bar response).
 Three replicates were taken for plant stems with calipers (Stem Diameter
 in units mm), plant height with a measuring tape (in units cm), and
 whether tassels were present. Later and in the lab, cob mass (in units
 grams) was collected after drying in oven. Leaf temperature data (**Leaf
 Temperature\_Dryad\_October2023**) is structured with ID and treatment
 columns, followed by the averaged daily temperature (in units Celsius)
 collected by Hobo data loggers with thermocouples adhered to the bottom of
 corn leaves in the lower third of plants. Leaf nutrient data
 (**LeafNutrients\_Dryad\_October2023**) were collected in 2020 and
 structured with ID and treatment columns, followed by nitrogen and carbon
 (in units percent dry mass) as determined by combustion using an elemental
 analyzer. Soil moisture was collected in 2020 and 2021, while soil
 nutrient data was collected only in 2020 (**Soil\_Dryad\_October2023**).
 Data are structured with ID and treatment and logger columns, followed by
 response variables of nitrate (NO3 in units ppm), nitrite (NO3 in units
 ppm), and soil moisture in volumetric water content (expressed as unit
 percentage). Spider mite density data **(MiteAndEgg
 Density\_Dryad\_October2023**) includes the treatments irrigation (High or
 Medium or Low), Corn Tolerance (Drought Susceptible or Drought Tolerant),
 and Species (Banks Grass Mite or Two Spotted Spider Mite or No Mites). N/A
 data indicate samples not used for calculating estimates. Spider mite
 motile (adult female) and egg data (**Morphometrics\_Dryad\_October2023**)
 includes the treatments irrigation (High or Medium or Low), Corn Tolerance
 (Drought Susceptible or Drought Tolerant), and Species (Banks Grass Mite
 or Two Spotted Spider Mite or No Mites). N/A data includes replicates
 where mites or eggs were damaged or otherwise unavailable for analysis.
 Final sampling period corn data (**Plant Field
 Measurements\_Dryad\_October2023**) includes the treatments irrigation
 (High or Medium or Low), Corn Tolerance (Drought Susceptible or Drought
 Tolerant), and Species (Banks Grass Mite or Two Spotted Spider Mite or No
 Mites). N/A data indicates that either two or three sampling replicates
 from each corn cage were collected, while cob mass was not collected in
 the field but rather later in the lab following the field collection. Leaf
 temperature data (**Leaf Temperature\_Dryad\_October2023**) includes the
 treatments irrigation (High or Medium or Low), Corn Tolerance (Drought
 Susceptible or Drought Tolerant), and Species (Banks Grass Mite or Two
 Spotted Spider Mite or No Mites). There were no missing or otherwise
 unavailable averages. Leaf nutrient data
 (**LeafNutrients\_Dryad\_October2023**) includes the treatments irrigation
 (High or Medium or Low), Corn Tolerance (Drought Susceptible or Drought
 Tolerant), and Mite Species (Banks Mite or Two Spotted Spider Mite or No
 Mites). %N indicates the percentage of nitrogen to dry mass and %C
 indicates percentage of carbon to dry mass. Soil moisture data includes
 reference to the data and time of data collection, Data Snap ID and Name
 (logger numbers and assigned names), and lastly volumetric water content,
 while soil nutrients data includes the treatments irrigation (High or
 Medium or Low), Corn Tolerance (Drought Susceptible or Drought Tolerant),
 and Mite Species (Banks Mite or Two Spotted Spider Mite or No Mites)
 followed by responses nitrate (NO3 in parts per million, ppm) and nitrite
 (NO4 in parts per million, ppm) (**Soil\_Dryad\_October 2023**).