TITLE: USDA LTAR Common Experiment measurement: Crop scouting for pests and diseases
AUTHORS: Brook J. Wilke

[DESCRIPTION]
Measuring pest and disease frequency and abundance can be cumbersome but contributes to important knowledge for research and management of cropland sites. Most LTAR Sites are assumed to lack the combination of knowledge and time to appropriately monitor crops for pests and diseases across the growing season. This protocol provides a format for hiring a contracted crop scout to monitor pests and diseases throughout the growing season.

[GUIDELINES]
Crop scouts will generally develop pricing based on the number of acres and different crops they are asked to survey. Include all details about the number of crops and expected locations for each visit so the crop scout can develop an appropriate price and time structure.

Expect each crop scout visit to last at least two hours and up to eight hours, depending on the number of treatments and crop entry points studied. 

[STEPS]
SECTION: Sample collection, processing, and analysis
1. Hire a professional crop scout to observationally scout all treatments every other week throughout the growing season. 

During each visit, include one replication at the plot and field scale for all treatments and rotation entry points. Rotate to a different replication at each subsequent visit so that all replications are visited equally over the year. 
Project managers should have continuous monitoring of pests and diseases to inform these visits, and at least one manager should accommodate the crop scout during each visit.

SECTION: Sample collection, processing, and analysis
2. Crop scouts should be monitoring crops for:

fungal diseases
viral diseases
insect pests
vertebrate pests
weed invasions

 

SECTION: Sample collection, processing, and analysis
3. The scout may advise sending samples to a laboratory for diagnosis, as some diseases and pests may be unidentifiable in the field.

SECTION: Sample collection, processing, and analysis
4. LTAR Sites may choose to monitor specific pests or diseases more intensively. This activity could include a pest or disease that is particularly impactful to the crops grown at the site or occurs in narrow windows of time not accurately captured by the bi-weekly crop scout visits. 

Site staff should develop a sampling plan including observations by the crop scout but layers more intensive observations and sampling by site staff.

SECTION: Covariate metrics to be sampled concurrently
5. Scouts should also make other crop observations while examining the plots and fields, including: 

GPS coordinates for observation locations
crop phenological stage
abiotic stress (e.g., drought and soil crusting)
plant population
nutrient deficiencies
other crop observations

SECTION: Calculations
6. The calculations vary depending on the disease or pest the crop scout identifies. When feasible to quantify disease or pest levels, the site may want to calculate this level based on a unit of area or other units commonly used to make management decisions. 

For example, some management thresholds may involve the number of insect pests per plant, whereas others may be calculated per acre or hectare. The most important aspect is documenting the pest level for scaling according to future needs.

SECTION: Quality assessment and quality control
7. Follow similar protocols within and across seasons. If different scouts are hired over time, ensure consistency in monitoring protocols is sustained.

SECTION: Archiving
8. Record and save a paper or digital log of each visit. Some diseases or pests may be archived for future investigation or curation. The specifics of these archives are up to each site.