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Seven candidate materials were evaluated in the field against populations of Phyllocoptruta oleivora (Ashmead). Five materials gave effective control of the citrus rust mite for 6 weeks compared with 4 weeks control for chlorobenzilate, used as a standard. The 5 materials giving satisfactory control included Acarol--isopropyl 4,4'-dibromobenzilate; formetanate hydrochloride; 3M MBR-5667--2-methyl-1,3-dithiolane-2-carboxaldehyde O-(methylcarbamoyl) oxime; Stauffer R-10044 65W--N-[(1,1,2,2-tetrochloro-2-fluoroethyl)thio]methanesulfonannilide; and Upjohn U-27, 415--benzoyl chloride (2,4,6-trichylorophenyl) hydrazone. Armored scale populations consisting of Lepidosaphes beckii (Packard), Parlatoria pergandii Comstock, and Aonidiella citrina (Coquillett) ranged from a combined low of 0.24 scales per leaf in the untreated check to a high of 0.80 scales per leaf in the U-27, 415 plots 9 weeks posttreatment. Differences were not significant. Scale parasite populations consisting of Aphytis lepidosaphes Compere, A. hispanicus (Mercet), Aphytis spp., Prospaltella elongata Dozier, P. fasciata Malenotti, and Prospaltella sp. were also apparently normal in all plots at 9 weeks posttreatment.

Fisher (1956) first found that zineb controlled russetting on citrus in Florida. As a result small amounts of zineb were used commercially in 19,57, and since that time zineb has been generally the miticide of choice for control of citrus rust mite, Phyllocoptruta oleivora (Ash.). Johnson et al (1957) reported on the use of zineb in more detail. They showed that chlorobznzilate was also quite effective, but nabam (sodium ethylene bisdithiocarbamate) and nabam plus zinc sulfate were found to be markedly inferior as compared with zineb. They also stated "although no variation in thoroughness of application was attempted, it is believed that thorough coverage of all fruit and leaf surfaces are needed for optimum rust mite control with zineb." Johnson (1960) reported that copper reduced the efficacy of zineb and he again recommended thorough applications. As a result of continued work, he reported in 1961 that a combination using chlorobenzilate at postbloom time, zineb in the summer, and wettable sulfur in the fall of the year was a satisfactory program for citrus rust mite control. Griffiths (1960) discussed the use of zineb in a commercial grove operation during 1958 and 1959. He concluded that zineb in combination with copper was not as effective as zineb alone and that where severe infestations occurred at the time of application, the efficacy of zineb was materially educed. Under these circumstances, increasing the zineb appeared to improve results. During the five years, 1957 through 1961, that zineb has been in use as a miticide on Florida citrus, materially different results have been obtained during the last two years as compared with the first three. Between 1957 and 1959 rust-mite control following zineb applications was almost spectacular. In many instances sprays applied in June or July resulted in extremely low rust-mite populations throughout the remainder of the summer and fall and even until the post-bloom application was made the following spring. During the summer of 1960 an entirely different situation arose. In many cases rust-mite control lasted only 30-60 days. Rust-mite control was difficult throughout the winter of 1960-61 and populations were extremely high during the spring of 1961. Both spring and summer applications of zineb in 1961 were often ineffective. The data presented here were obtained in an effort to determine the comparative effectiveness of wettable zineb (zinc ethylene bis-dithiocarbamate) and a tank-mix of the diammonium salt reacted with zinc sulfate; to test the necessity for thorough coverage when zineb was used; and to find some basis for an explanation of the inferior control obtained -with zineb in 1960 and 1961.

Chlorobenzilate was investigated to establish the analytical method of it by ECD-gas chromatography.From activated carbon column, organochlorine insecticides including chlorobenzilate were eluted by the mixture of n-hexane and ethylether (1:4), but δ-BHC was not recovered in the step.In florisil column chromatography, chlorobenzilate was completely separated from other organochlorine insecticides, that is, the latter were eluted by the mixture of n-hexane and ethylether (4:1) and the former was contained in the second eluate of n-hexane, acetone and ethylether (3:1:1).In the analytical method of organochlorine insecticide residues including chlorobenzilate in some fruits devised in this study, recovery test of them added to samples gave good results (70% of aldrin in rind of summer orange to 109% of pp′-DDT in summer orange).