Abstract
The effect on insect populations of the widespread use of plant growth regulators and herbicides is a neglected field. Fox (1948) reported on a relationship between the use of 2,4-D and wireworm damage to wheat. Putnam (1949) suggested that 2,4-D could be an environmental factor in the ecology of grasshoppers. A recent report (Maxwell and Harwood, 1958) indicates that even slight dosages of 2,4-D increase the rate of reproduction of pea aphids on broad beans. This note is a preliminary report on similar investigations with the pea aphid, Acyrthosiphon pisum (Harris), and broad bean, Vicia faba L.