The development of resistance to hydrocyanic acid in certain scale insects

Inheritance of resistance to hydrocyanic acid fumigation in the California red scale

“…Banana squash and, later, grapefruits were infested from these stocks at intervals of approximately six months and fumigated to determine whether these strains would maintain their difference in susceptibility to HCN. Preliminary results (Quayle, 1938) showed that the differences were maintained through several generations; later results have confirmed this (Lindgren, 1941) and show that resistance to fumigation is inherited.…”

Variation and Adaptation in the Imported Fire Ant

“…Their history illustrates the extremely rapid rate with which such a change, which can be interpreted as an initial step in subspeciation, can occur in a population of insects. Similar changes have been observed in populations of the scale insects Aonidiella aurantii, Coccus pseudomaqnoliarum, and Sassieta oleae (Quayle, 1938), and of the codling moth, Carpocapsa pomonella (Hough, 1934, andBoyce, 1935).…”

Factors influencing the results of fumigation of the California red scale

“…Factors affecting fumigation results, such as temperature and humidity (Quayle and Rohrbaugh, 1934), exposure of scale insects to sublethal concentrations of HCN before regular fumigation (Gray and Kirkpatrick, 1929;Pratt, Swain, and Eldred, 1931;Moore, 1933;Lindgren, 1938), stages of insects (Quayle, 1920;Moore, 1934), length of exposure to HCN (Swain, 1918;Kirkpatrick, 1939), and type of concentration (Pratt, Swain, and Eldred, 1931;Cupples, 1933;Moore, 1933 ;Lindgren, 1938), have been studied both in the laboratory and in the field. The results obtained by the investigators have not always been in agreement, owing probably to a large extent to the fact that the scales used for experimental purposes were obtained from the field in several or many different groves.…”