Control of Pecan Nut Casebearer

Abstract

A review of current literature shows that great progress has been made in the control of pecan insects by the use of insecticides during the past two decades. For example, prior to 1945, the recommended control measure for the pecan nut casebearer Acrobasis caryac Grote, was 13 fluid ounces of 406X0 nicotine sulfate plus 2 quarts summer oil emulsion per 100 gallons water. In 1962 pecan growers had a choice of five different insecticides that were recommended for the control of the nut casebearer. These insecticides were: DDT, EPN, Guthion, malathion and parathion. Each of these materials is much more effective in controlling the nut casebearer than the formerly recommended nicotine sulfate plus oil. Although the above recommended insecticides give effective control of the nut casebearer on pecans as recommended, some materials are expensive and would not be economical to use on a large scale. Work is being continued with these insecticides in an effort to determine whether the amount of material recommended can be reduced, without reducing the effectiveness. Studies are also being made to determine whether the more costly materials can be combined with a less expensive material in such a manner that when applied the spray will be more economical for the grower, yet still give effective control of the casebearer. In the spring of 1962, malathion, parathion and combinations of malathion plus DDT and parathion plus DDT were used in two separate experiments to evaluate and compare their effectiveness as a control for the nut casebearer. In one of these experiments, south of Lloyd, Florida, preliminary tests were also made with four new materials to determine their effectiveness as a control for the first generation nut casebearer larvae. Parathion, malathion, Thiodan, Bayer 37344, Bayer 44646, Ethyl-Methyl Guthion and combinations of parathion plus DDT and malathion plus DDT were applied one time to single tree plots. All treatments were used as sprays and applied with a hydraulic sprayer (Bean Royal 35 MT). Plots were randomized within each block, and blocks were replicated seven times. An unsprayed plot was used as a control. (See Table 1 for formulations and concentrations used.) The second experiment was set up at the Simpson Nursery Company orchard at Monticello to check the effectiveness of malathion and parathion alone and in combination with DDT as used in the first test. The plot design and method of application used in this test were the same as that used in the Lloyd experiment, except plots were replicated only six times. (See Table 2.) The rieasons for using the malathion plus DDT and parathion plus DDT combinations in these separate tests were to evaluate their effectiveness in controlling the nut casebearer, as compared to the malathion and parathion sprays used in the present recommendations for control and to determine whether the malathion plus DDT and parathion plus DDT combinations would cause a build up in aphid and mite populations.