When a winegrape grower decides it is necessary to use a pesticide, he must evaluate which one to use. Considerations include at least the following: level of the pest infestation, efficacy of the material, length of time until harvest, size of the crop, the presence of damage from any other pests—and terms of contracts with winery customers. Many growers are also deeply concerned about the risk the application poses to themselves, their workers and the environment in and around the vineyard.