Select a crop that is similar to the crop to which pesticides are being applied; a similar crop is one that has a similar attractiveness to pollinators and growth habit, which influences how farm workers come into contact with the crop from planting to harvest. The active ingredient, application rate and application method have the biggest influence on the risk results in most cases.
Crop specificity is most important for the worker dermal, dermal cancer, pollinator and consumer dietary risk indices. For the worker dermal and dermal cancer indices, harvest and cultivation methods (hand-scale vs. mechanized) can affect the amount of contact workers have with the crop and pesticide. For the pollinator indices, risk scores depend on the attractiveness of the crop to pollinators and the bloom date of the crop. By selecting a crop with similar growing and pollinator patterns, the risk scores for the worker dermal, dermal cancer and pollinator indices will be sufficiently similar. For the consumer dietary indices, the amount of pesticide residue consumed varies depending on how the crop is consumed and how much of the crop is consumed. Consumer Dietary risk scores are specific to the selected crop, and therefore substitute crops will not provide accurate dietary risk scores.
For example, for walnuts, run PRT on almonds for worker dermal and dermal cancer; and on grapes for pollinator risk scores. There is no substitute crop for the dietary indices.