Susceptibility of Winter Eggs of the European Red Mite to Petroleum Oils and Dinitro Compounds1

Abstract

Petroleum oil sprays of varying concn. were applied at the beginning of hatching of winter eggs and at 6, 16, 21 and 39 days before hatching. The same oil was used in all lots. Egg susceptibility increased as the interval between treatment time and hatching was reduced. Thus 39 days before hatching a 3% oil concn. gave only 91.6% kill, while 90.2% kill of eggs was obtained with a 0.25% concn. applied at the beginning of hatch. Dinitro-o-cresol proved ineffective, whereas at 0.5% a formulation containing 36% of the triethanolamine salt of dinitro-o-secondary butyl phenol gave an efficiency of 97.2%.