Studies on the Use of Malathion on Citrus1

spray mixtures and data on control are given in table 1. Protection from Ovotran plus parathion, oil emulsion plus parathion, EPN plus parathion, demeton, and schradan lasted through the rest of the year, at least 283 days. Protection from Aramite plus parathion lasted 71 days. The other treatments controlled red mites for only 37 days and allowed a heavy summer infesta tion to develop. In 1954 all trees were sprayed on April 16-20 with nutritional materials including cop per, zinc, and manganese. Fifty of these trees received parathion and wettable sulfur in this spray, 10 had oil emulsion, 10 emulsive malathion plus wettable sulfur, 10 demeton plus the sulfur, and the remaining 10 schradan plus wettable sulfur. The experimental miticides were omitted because citrus red mite infesta tions were low, not more than 2 to 5 percent on the leaves. After the treatment, red mite infestations developed rapidly, and by May 26 had reached 49 to 60 percent in the trees that had received parathion. Emulsive ma lathion and schradan allowed almost as heavy a build-up, but there was none on trees that had received demeton or oil emulsion. On June 7 experimental miticides were ap plied to the trees in the treatments that had high infestations. The miticides were Ovo tran, EPN, Mitox (20-percent p-chlorobenzyl p-chlorophenyl sulfide), Isolan (25-percent 1 -isopropyl-3-methyl-5-pyrazolyl dimethylcarbamate), malathion wettable, emulsive malathion, and schradan. Heavy rains totaling 10.54 inches during the next 60 days shortened the protection from these sprays, but Ovotran and EPN were superior to the others. All these miticides were reapplied on July 26, with good control. On August 13 no mites could be found on trees sprayed with EPN, Mitox, demeton, or schradan. The trees sprayed with Ovotran or oil had less than 1 percent, with emulsive malathion less than 2 percent, and with wettable malathion and Isolan 3 percent infestation. During this period infestations were declining naturally. In the examinations made September 16, in festations had increased in all treatments ex cept schradan. Among the miticides tested in combination sprays during 1953 and 1954, the newer ma terials Mitox, Isolan, demeton, and schradan controlled citrus red mites as well as did oil emulsion, Ovotran, Aramite, or EPN. Ma lathion was also satisfactory for control when used twice during the year.