Appendix 4. Pesticide Application

Harvesting Methods and Fresh vs. Processed Products

Background

Pesticide registrations consider human exposures during crop production, harvesting, and market use. Notes on pesticide applications were summarized from our grower surveys (see References in appendix) for overviews on methods of application and equipment.

Pesticide applications during production

For weed control, growers predominately apply their own herbicides, ranging from 71% in peanuts to 97% in sugarcane, as shown in Table 24. Ground equipment is predominately used for herbicides (73 to 93% of the time), usually tractors with enclosed cabs. Less than 5% is applied by aircraft – with enclosed cockpits and GPS guidance systems. Spot applications, to treat escaped or scattered clumps of weeds, involves workers using hand guns. Spot treatments are applied on 2% of the peanut acreage to 25% in sugarcane where perennial grasses are a major problem. For insecticide applications, growers relied more heavily on custom applicators (see cotton example below; few insecticides are applied to peanuts or sugarcane). While we do not have data for vegetables, some extrapolations can be made; most herbicides are applied by growers and insecticides are predominately by aircraft since timely treatment is essential and the crop canopy limits use of ground equipment.

Table 24. Pesticide application, harvesting methods, and fresh vs. processed products
Type of Application Herbicide Treatments (percent of acres) Insecticide Treatments (percent of acres)
cotton
peanuts cotton sugarcane
Grower applied 71 84 97 51
Custom applicator 29 16 3 49
Ground equipment 93 85 73 54
Aerial equipment 5 3 2 46
Spot or other 2 12 25 0

Harvesting methods

The information in Table 25 was obtained from knowledgeable exports on methods of harvest and end use (markets) for 20 horticultural crops. Many horticultural crops are hand harvested, ranging from 2% in carrots to 100% in many other crops. Machines may be used where once-over and mechanical harvesting is possible. The re-entry level (REI), days between the last pesticide application and when a worker can re-enter a field without personal protection equipment (PPE), becomes critical. Worker tasks may involve weeding, pruning, irrigation, scouting for pests, and particularly hand harvesting.

Markets

Intended end use of the product is a major consideration. For example, processed fruits usually have less residue potentials than fresh products. The pre-harvest interval (PHI) is the length of time between the last application and allowable harvest.

Table 25. Harvesting methods and end uses (fresh market vs. process) for major horticultural crops
Crops in Texas Harvest method (percent) Market (percent) Notes
Hand Mechanically Fresh Processing
“By Hand” – people’s hands involved in pick up or individual loading of products, not bulk handling.
“Mechanical” – primarily machine dug, picked, and/or loaded; commodity is not individually handled.
Roots, tubers, & bulb
Carrot 2 98 60 40 Lifted. Tops cut by hand
Potato 2 98 85 15 Totally mechanized
Sweet potato 2 98 90 10 Some hand pick up
Greens 100 0 100 0 Labor intensive
Onions 98 2 95 5 Dug mechanically
Tops & roots clipped by hand
Most others 100 0 100 0
Leafy veggies and greens
Lettuce 100 0 100 0
Spinach 2 98 50 50
Dandelion, kale, cilantro, parsley, mustard, and Swiss chard 100 0 100 0 Harvests cost $1,600 to $2,400 per acre (multiple harvests)
Cole Crops
Cabbage 100 0 100 0
Collards and greens 90 10 70 30
Beans and peas
Green/snap beans 2 98 10 90
Dry beans 0 100 5 95
Succulents & Southern peas 5 95 15 85
Fruiting Vegetables
Peppers – bell & chili 80 20 30 70 Plains – all mechanically harvested
Tomato 100 0 100 0
Melon/vine crops 100 0 80 10 Some cukes mechanically harvested
Citrus/subtropic tree crops 100 0 85 15
Apples, pears, others 100 0 100 0 30% thinned by hand
Berries – all 60 40 100 0 Mechanical shakers used
Nuts – pecans 15 85 60 40 Shakers with mechanical pick-up.
Misc. crops (CG 20) highly variable with crop variable with crop

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