Harvesting Methods and Fresh vs. Processed Products
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.
|Type of Application||Herbicide Treatments (percent of acres)||Insecticide Treatments (percent of acres)
|Spot or other||2||12||25||0|
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.
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.
|Crops in Texas||Harvest method (percent)||Market (percent)||Notes|
|“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|
|Sweet potato||2||98||90||10||Some hand pick up|
Tops & roots clipped by hand
|Leafy veggies and greens|
|Dandelion, kale, cilantro, parsley, mustard, and Swiss chard||100||0||100||0||Harvests cost $1,600 to $2,400 per acre (multiple harvests)|
|Collards and greens||90||10||70||30|
|Beans and peas|
|Succulents & Southern peas||5||95||15||85|
|Peppers – bell & chili||80||20||30||70||Plains – all mechanically harvested|
|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|