Lithium As a Fungicide on Celery
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DARBY AND WESTGATE: LITHIUM FUNGICIDE 59 toria apii (Br. and Car.) Chester) and are were either equal to, or not as good as, the recommended for the control of late blight, wettable powder. The yield was nearly twice that of the un Dyrene (2 lbs.—100 gal.) plus Agri-mycin treated. (200 ppm) looked unusually good in late Some tank mix fungicides were better than blight control on an outside guard row which the same chemical prepared as a wettable was not randomized. powder by the manufacturer, whereas some LITHIUM AS A FUNGICIDE ON CELERY J. F. Darby and P. J. Westgate on celery. Larger concentrations of lithium in the soil had a more pronounced effect on the Central Florida Experiment Station disease, but were toxic to the host plants. Sanford In order to determine if lithium compounds would have the same effect on controlling Recently Kent (3) in England has reported early blight (Cercospora apii Fres.), the fol on the fungicidal action of lithium compounds lowing experiments were conducted. on a disease of celery caused by the fungus Soil Applications of Septoria apii. This paper showed that lithium Inorganic Lithium Compounds chloride and lithium nitrate at concentrations between one and four milligram equivalents On January 26, 1956, equivalent Weights of of lithium (Li) per liter of soil reduced the lithium compounds were applied to Pascal amount of a leaf spot disease (Septoria apii) celery plots which had been planted Decem ber 9, 1955, at Sanford. Table 1 shows the Florida Agricultural Experiment Station Journal Series, No. 808. effect of lithium compounds on control of Table 1.- Results of various lithium compounds applied to the soil around celery plants. Lithium Pounds per acre Disease Celery yield Ppm Li in compounds a/ of lithium index b/ lbs./plot leaves compound (oven dry basis) Lithium chloride 187 0.12 131. 900. Lithium carbonate 163 0.0? 10?. 900. Lithium hydroxide 106 0.15 130. 900. Check 0 2.70 176. 200. a/ Lithium compounds and grant-in-aid furnished by Foote Mineral Company, Philadelphia. b/ Based on a scale ranging from 0 (no early blight) to 5 (maximum early , blight). c/ Lithium analyses by Dr. Nathan Gammon Jr., Gainesville, Florida. 60 FLORIDA STATE HORTICULTURAL SOCIETY, 1958 early blight, yield and lithium content of lithium carbonate, lithium hydroxide and lith celery at harvest. No other fungicides were ap ium nitrate—were applied to the soil around plied. young celery plants which had been trans Thus when lithium compounds were added planted to the field February 20, 1957. On to the soil at the rate of 100 to 200 pounds May 20, 1957, early blight and chemical in per acre, there was a 95 percent reduction in jury ratings were made as shown in Table 2. disease accompanied by a 30 percent reduc Thus, although there was a marked reduc tion in yield of celery. A scorching of the edges tion in the amount of early blight of celery of the celery leaves (marginal necrosis) was with each additional amount of lithium com characteristic of the injury caused by the pound applied to the soil, even up to 125 lithium. The lithium acted as a systemic fungi pounds per acre, 50 pounds per acre of any cide moving into the plant from the soil (4). one of the four lithium compounds appears On April 4, 1957, various amounts of the optimum. Above 50 pounds per acre there following lithium compounds—lithium chloride, was usually a leveling off of celery yield with Table 2.- Effects of soil applications of various lithium compounds on celery (1957)• Th© figures are averages or totals of four replicates. Soil Lithium Early blight Injury Celery yield treatment compound rating a/ rating b/ lbs./plot Lithium chloride 0 2.**4 0.00 3.31 n n 25 2*13 0.12 4.31 n ti 50 1.50 0.50 4.34 n n 75 1.00 1.19 3.88 tt it 100 0.38 1.13 3.40 ti n 125 0.25 1.19 2.20 Lithium carbonate 0 2.66 0.00 3.34 it tt 25 2.19 0.12 3.89 u tt 50 1,69 0.50 3.98 ti ti 75 1.56 1.13 3.89 n ti 100 0.69 1.31 3.80 ft n 125 0.50 1.31 3.77 Lithium hydroxide 0 2.50 0.00 3.30 n n 25 2.00 0.19 3.72 it it 50 1.08 0.56 3.70 n it 75 1.06 1.06 3.81 n it 100 0.31 1.31 3.94 n it 125 0.50 1.19 3.27 Lithium nitrate 0 2.63 0.00 3.64 ti it 25 2-13 0.25 4.10 it n 50 1.88 0.38 3.97 n n 75 1.50 0.81 4.14 n tt 100 0.56 0.87 3.91 a tt 125 O.56 0.94 3.00 a/ 0 » No blight 5 - Maximum blight b/ 0 = No chemical injury 5 = Maximum injury DARBY AND WESTGATE: LITHIUM FUNGICIDE 61 actual decreases in yield at 125 pounds per plant plus a marginal necrosis of the leaves acre in comparison to the yield from untreated (2). checks. In celery and sweet corn fungicide trials in Zellwood (1958) lithium carbonate was used Foliar Applications of at 2 pounds per 100 gallons per acre for 5 Inorganic Lithium Compounds applications on sweet corn and 10 applications Since the minimum quantity of soil applica on celery, making a total of 10 and 20 pounds, tions of lithium salts necessary to control early respectively, per acre. At this rate no phyto blight was too large to use on celery without toxicity was noted in celery, but it produced causing severe stunting and injury, attention a moderate chlorosis of the entire sweet corn was focused on foliar applications. plant. In previous celery tests if enough lith In April, 1956, a preliminary spraying trial ium carbonate was sprayed on the plants to was designed to find which of three lithium control early blight it also produced phytotox compounds, namely, lithium chloride, lithium icity. The 1958 tests on celery and sweet corn carbonate and lithium hydroxide, was the least showed that when the quantity of lithium carbonate was reduced low enough to cause phy to toxic when sprayed on celery and to no phytotoxicity, it did not control the disease. determine the maximum concentration which could be sprayed on celery without producing Foliar Applications of any phytotoxicity. One, 5 and 10 pounds of Lithium Carbamates each of the three lithium compounds per 100 gallons of water were applied as a foliar spray A preliminary test was conducted on celery to celery. The sprays were used at the rate of in the spring of 1957 in which the lithium 450 gallons-per-acre, totaling 4.5, 22.5 and salts of sodium dimethyl dithiocarbamate 45.0 pounds of each compound per acre. (20%) and sodium ethylene bisdithiocarbamate Lithium carbonate proved to be the least (10%) at the rate of 2 and 4 quarts, respec phytotoxic and the maximum concentration tively, in 100 gallons of water showed less that could be used without producing phyto phytotoxicity than other forms of lithium pre toxicity was between one and 5 pounds per viously tested. No disease control data were 100 gallons (1). obtained from this preliminary test. Lithium carbamates were included in a cel The 1956 fungicide trial on celery with 10 ery fungicide spraying trial conducted in spring treatments had received 6 applications when 1958. Altogether there were 30 treatments the results of the above preliminary trial be with four replications. The treatments were ap came available. Four pounds of lithium car plied 15 times at an average of 150 gallons bonate per 100 gallons of water was substi per acre per application. Data from five of tuted in this trial for a fungicide which was the treatments are presented in Table 3 for not controlling early blight. The remaining 8 comparative purposes. Both forms of late applications of lithium carbonate totaled ap blight, Septoria apii graveolentis Dor. and S. proximately 32 pounds per acre. This amount apii (Br. and Cav.) Chester, were present in of lithium significantly reduced (with statis approximately equal quantities. Dilithium tical odds of 19 to 1) the incidence of early ethylene bisdithiocarbamate was as good as blight below that of the untreated, but also nabam plus ZnSO4 in late blight control, but produced a slight stunting and marginal ne not in yield (Table 3). The other two lithium crosis of the leaves. compounds did not give satisfactory disease In the 1957 celery fungicide trial lithium control or yields. The marginal necrosis of carbonate was included as one of 23 treat the leaves, typical of the effects of spraying ments at a concentration of 3 pounds per 100 with lithium carbonate in previous tests, was gallons and at the average rate of 80 gallons not present when sprayed with the lithium- per acre for 14 applications, making a total of carbamates. There was an increase in the 33.6 pounds of lithium carbonate per acre. length of the ribs of the celery stalks from This amount of lithium significantly reduced those plots receiving lithium in comparison (at the 1% level) the incidence of early blight with the untreated checks. On the other hand below that of the untreated, but, as in previous the length of the ribs from the lithium plots tests produced a slight stunting of the entire were less than those from the nabam-zinc plots.