Progress Reports of Agricultural Research, published by the University of California Colkge of Agriculture, Agricultural Experiment Station Vol. 2, No. 4 SPECIAL PROGRESS REPORT April, 1948 ORGANIC PHOSPHATE INSECTICIDES Results Obtained in 1947 with Phosphate Insecticides by the Division of Entomology and Parasitology at Berkeley and Davis

The following reporis cover experimental results obtained by various workers in the Division of Entomolop y with phosphate insecticides in 1947. They are, for the most part, preliminary in nature arid should not be construed as Fnal recommendations for the control of the pests concerned. Much additional information is needed, in most cases, particularly on the toxicity of these chemicals to man and the possibility of a poisonous residue remaining on sprayed food stuffs. It is known that some of the phosphate insecticides are readily absorbed through the skin and concentrates arid solutions in oil should be handled with extreme care. Although the phosphate compounds are usually nontoxic to plants at concentrations which will kill insects, certain species and varieties of plants have shown a susceptibility to iir jury by these compouitds. E. 0. ESSIG,Chairninrt o! /he Division

Ilv OCTOBER 1946, J. T. Thurston of the probably contains about 20>4 of tetra- Technical Industrial Intelligence Division ethyl pyrophosphate, together with 805, of the U. S. Department of Commerce of other organic phosphates and the com- CONTENTS published his report entitled “Organic mercial so-called lOOC/r, tetraethyl pyro- Chemical Intermediates for Insecticides, phosphate probably contains about 407; Grape Bud Mite Tests...... 2 Fungicides and Rodenticides,” FIAT of this chemical, together with 60% of Final Report 949, Office of Military Gov- other organic phosphates. In the follow- Red Spiders on Grapes...... 2 ernment for Germany (US).This report ing reports the initials HETP are used to Aphids, Mites on Pears, Prunes. .... 5 sets forth certain technological advances represent the commercial hexaethyl tetra- in insecticide synthesis which were devel- phosphate containing about 202) tetra- Melon Insects and Mites...... 6 oped in Germany up to the end of the war. ethyl pyrophosphate; and the initials Of the five insecticides described in the TEPP are used to represent commercial Walnut Aphid ...... 7 Thurston Report, two were phosphate te tr aeth yl p yrop hosphate containing OliveScale ...... 8 compounds. The first of these was known about 40% of this compound. under the German trade name of Bladan The second insecticide described is now FigScale ...... 9 known in the United States under the and contained 70% hexaethyl tetraphos- Black Scale on Olives...... 10 phate and 30%’of a wetting agent. It is common name parathion. The chemical now offered for sale under a number of name for parathion of 0, o-diethyl 0, Grape Leafhopper Tests...... 11 trade names. p-nitrophenyl thiophosphate. The yield of It is believed that the German process this chemical in commercial manufacture Aerosol Fog ...... 12 of synthesis, and modifications of it used is said to be 90% to 95%. The name Field Tests on Grapes...... 13 in the United States. do not produce parathion is used in these reports to desig- hexaethyl tetraphosphate, but rather a nate this 90%) to 95% material. California Cotton Insects...... 16 The information developed to date by mixture of organic phosphates. One of Greenhouse Plants ...... I5 these has been identified as tetraethyl the experiments with organic phosphates pyrophosphate and it composes about has some immediate practical application Alfalfa Butterfly Tests...... 18 20% of the total yield. and, therefore, is made available in this Tetraethyl pyrophosphate has shown form before completion of the research Tests on Bees...... 20 high toxicity to insects. and methods have and formal publication of results. Mosquito Larvae ...... 22 heen devised for its synthesis. The yield of tetraethyl pyrophosphate is believed to LESLIEM. SMITH Spring Dwarf Nematode...... ?3 be about 40%. The commercial, so-called Associate Entomologist in 100% hexaeth yl tetraphosphate therefore the Experiment Station

CALIFORNIA AGRICULTURE, APRIL, 1948 3RGANIC PHOSPHATE INSECTICIDES