' L I B R. A R. Y OF THL UNIVERSITY OF ILLINOIS 00.433-444 P CIRCULATING r UNBOUND CIRCULATING CORY; OIL BAITS for Grasshopper and Armyworm Control By M. D. FARRAR. W. P. FLINT, and J. H. BIGGER 100 Tons were used in Illinois in 3088 Tons were used in Illinois in Bulletin 442 University of Illinois Agricultural Experiment Station In Cooperation with the Illinois State Natural History Survey o IL BAITS for armyworm and grasshopper con- trol in Illinois were first tested in 1934. Experi- ments and the experience of farmers who used these baits soon established a preference for them over baits containing molasses. In the 1937 state-wide campaign for grasshopper control an oil-bait program was followed. More than 3,400 tons of poisoned bait was spread, about 90 percent of which was made with oil as the binder. Thus this type of bait was given a practical test on some 600,000 acres of the principal Illinois crops. Farmers liked the ease with which the oil baits could be mixed, stored, and spread, and grasshopper control was in general satisfactory where this kind of bait was used. Another merit of the oil bait was that it caused less injury to tender foliage than did some other kinds of bait. Oil baits are therefore recommended to the farmers of Illinois because they have satisfactory killing qualities; when properly applied they do not easily injure tender crops ; and they are convenient to mix, store, and spread. Urbana, Illinois April, 1938 Publications in the Bulletin series report the results of investigations made by or sponsored by the Experiment Station Oil Baits for Grasshopper and Armyworm Control By M. D. FARRAR, W. P. FLINT, and J. H. BIGGER' HE DESTRUCTION of farm crops by insects has become a problem of increasing concern during the past decade as drouth ^ years have followed one another in rapid succession. Of the many methods and materials developed or tested for use against grass- hoppers, armyworms, and some other cutworms, certain poison baits containing lubricating oils have proved the most effective and practical under Illinois conditions. TESTS EXTENDED OVER FOUR YEARS The Illinois experiments with oil baits, briefly summarized in this bulletin, were begun in 1934 2 and continued thru 1937. They were suggested by work done in the Dakotas 3 in 1933. The Illinois field tests were conducted at three places in the state in 1934 on mixed populations of cutworms. An armyworm outbreak in western Illinois in 1935 afforded four additional tests on this pest. Two grasshopper experiments were also made the same year. The oil baits proved so effective in controlling both grasshoppers and armyworms in 1934 and 1935 that their more general use was recommended to Illinois farmers in 1936, a year when grasshoppers became destructive to farm crops thruout much of the state. Again the oil baits, both experimentally and in the hands of farmers and seeds- men, proved their worth. By means of these baits valuable isolation plots for the production of hybrid corn were saved from serious damage. Altogether about a hundred tons of oil bait was used by Illinois farmers this year. By 1937 the oil baits had so well demonstrated their value that 'M. D. FARRAR, Research Entomologist, Illinois State Natural History Survey; W. P. FLINT, Chief Entomologist, Illinois State Natural History Survey and Illinois Agricultural Experiment Station; and J. H. BIGCER, Associate Entomologist, Illinois State Natural History Survey. 'Bigger, J. H. Preliminary field tests of oil bait for cutworm control. Jour. Econ. Ent. 28, 130. 1935. 'Parker, J. R., Shotwell, R. L., and Morton, F. A. The use of oil in grass- hopper baits. Jour. Econ. Ent. 27, 89. 1934. 415 416 BULLETIN No. 442 [.April, 3,088 tons was reported by the Illinois farm advisers as used in the campaign that year against grasshoppers. This amount of oil bait constituted approximately 90 percent of all the poison bait used. While slightly higher in cost, it was preferred by most farmers to baits containing molasses and water because of its superior mixing, storage, and handling qualities. OILS OF 20-30 VISCOSITIES MOST SATISFACTORY Mineral oils with a wide range of chemical properties were tested during 1937. These were obtained from eight different oil companies and included twenty different trade-named brands. The prices of many of these oils are such as to make them practical for use in oil baits. The most satisfactory oils were mineral oils in the 20-to-30 viscosity range, the higher viscosity giving better results under very dry, hot conditions. Following are the specifications of an oil that was used extensively in these baits and gave good results: Viscosity SAE 20 Specific gravity 9212 Flash 365 min . Fire 410-420 Color NPA 4yi-5 Vegetable oils, including palm oils, coconut oil, and soybean oil have been tested in baits, but the mineral oils gave better results and are cheaper. BRAN-COB MIXTURE MADE EXCELLENT CARRIER As a carrier for the oil and the poison, wheat bran was found to be the best and cheapest material that is generally available. 1 Every elevator and feed store handles it. Farmers can purchase it well in advance of the time when it will be needed for grasshopper baits, and if weather conditions reduce the hoppers so that it is not needed for bait it can be used for feed. In the search for a still cheaper carrier, tests were made in 1937 of a mixture of bran and corncobs ground to the fineness of bran. No reduction in the efficiency of the mixture could be detected when the ground corncobs and bran were mixed in equal parts. In fact this mixture proved the cheapest and most effective bait tested under Illi- *A number of other materials including oat hulls, cottonseed hulls, sawdust, and various other commercial by-products were tested in 1937, but none proved equal to bran. 19381 OIL BAITS FOR GRASSHOPPER AND ARMYWORM CONTROL 417 nois conditions. When, however, the bran-cob mixture was more than half ground cobs, an inferior bait resulted. SEVERAL POISONS PROVED EFFECTIVE The most effective poisons used in these baits were refined white arsenic, crude white arsenic, dry sodium arsenite, sodium pyroarsenate, sodium fluosilicate, and paris green. All of these used at 4 pounds to 100 pounds of bran, or a bran and corncob mixture, have given very satisfactory kills. When sodium arsenite is used, only 3 pounds is necessary to 100 pounds of bran and corncob mixture. Liquid sodium arsenite did not prove satisfactory in the oil baits. OIL BAITS CONVENIENT TO MIX AND STORE One of the big advantages in the use of oil baits over those con- taining water and molasses is that they can be prepared some time in advance. Tests have shown that they can be stored for more than a year without deteriorating. With oil baits, as with any bait, thoro mixing of the ingredients is necessary in order to obtain good results. The bran and cobs, or bran alone, and the poison should first be thoroly mixed. Then the oil should be added and the whole thoroly stirred until every particle of the carrier is coated with oil. Storing the mixed bait for a month or more seems to improve it, as the oil permeates more thoroly thru the mixture and in this way a more uniform distribution is obtained. Any mixed bait should be conspicuously labeled POISON and stored where there will be no danger of its being used for animal feed. PLANT INJURY WAS LESS WITH OIL BAITS For grasshopper bait it is very important to use materials that will not burn the foliage of plants when it is sown broadcast over the field. The soybean, one of the principal crops in Illinois, has a very tender foliage, which, in the experience of the authors, is easily burned with liquid sodium arsenite water bait or with the water-molasses poison- bran bait. As shown by extensive field observations, some of the oil baits were much less injurious to this crop than the water baits. The only bait that did not injure soybean plants was a mixture of lubricating oil, bran, and paris green (Table 1). Any baits used on soybeans should be spread uniformly and at a rate not to exceed 10 pounds to the acre or serious burning may result. 418 BULLETIN No. 442 {April, TABLE 1. INJURY TO SOYBEAN FOLIAGE FROM WET BAIT AND FROM OIL BAIT (Treatment applied August 10, 1936; plants examined August 15) Kind of bait (10 pounds applied per acre) Leaves visibly injured Poison (with bran) Binder Upper leaves Lower leaves Paris green Oil. SAE 20 None Light to moderate Light Light to moderate Moderate None peril. 3 60 60 60 55 3 Sodium pyroarsenate Oil, SAE 20 Paris green Molasses and water . . Sodium pyroarsenate Water Sodium arsenite . Water No treatment OIL BAITS FOR ARMYWORM CONTROL During the seasons of 1934, 1935, and 1937 bran-oil baits were used successfully in the control of armyworms. The tests in the fall of 1934 included a series with the yellow-striped army worm (Prodenia orni- thogalli Guenee) and the fall armyworm (Ldphygma frugiperda S. & A.). In 1935 tests were run on the true armyworm (Cirphis unipuncta Haw.). The results of the tests in 1934 and 1935 are shown in Table 2. TABLE 2. ARMYWORM CONTROL: COMPARISON OF MOLASSES AND OIL IN BRAN BAITS, EXPERIMENTS IN WESTERN ILLINOIS, 1934 AND 1935 Crops attacked Poisons tested. 4 pounds per 100 pounds bait Binder, 2 gallons per 100 pounds bait Number of tests Average kill Relative efficiency 1934: Experiments with yellow-striped armyworm and fall armyworm Alfalfa Paris green Molasses*'! Molasses / Oil, SAE 30] Oil. SAE 30} Oil. SAE 30) None 2 4 3 Perct. 85.5 81.0 12.7< 83.4 77.1 Alfalfa White arsenic Paris green Alfalfa Sodium fluosilicate None 1935": Experiments with true armyworm Corn, rye, wheat Paris green Molasses* 3 67.0 62.3 Corn, rye, wheat Paris green Oil, SAE 30\ Corn, rye, wheat Sodium fluosilicate None Oil, SAE 30/ 18 4 69.4 12.5> These baits contained 10 gallons of water to 100 pounds of bait. b Natural mortality. 1938} OIL BAITS FOR GRASSHOPPER AND ARMY WORM CONTROL 419 Altho present in smaller numbers, other species also were killed by the baits. These were the corn ear worm (Heliothis obsoleta Fab.), alfalfa caterpillar (Eurymus eury theme Bdv.), and alfalfa looper (Autographa calif onica Speyer). A few garden webworms (Loxostegc similalis Guenee) were also killed where the bait was used in alfalfa, but satisfactory control of any of the above species was not obtained. No experiments in armyworm control were conducted in 1936. In 1937 the work was confined to field observation made in cooperation with more than a thousand farmers. In this year farmers thruout the state used oil baits in combating general outbreaks of this insect. Lack of control was encountered only in one section where a certain cheap oil having a very pronounced odor was used against the true armyworm. The armyworm larvae would not eat bait made with this oil, and farmers made rapid shift back to the bran-molasses bait. Oil from the same lot was used successfully in grasshopper bait. TABLE 3. GRASSHOPPER CONTROL: SUMMARY OF EXPERIMENTS WITH OIL BAITS USED AGAINST MIXED POPULATIONS OF GRASSHOPPERS (All lubricating oils included here are available commercially) li.ii I mixture Binder Num- ber Aver- Rela- tive Crops Base Poison of tests age kill humid- ity 1935 perct. Soybeans Bran Paris green Molasses and water 1 70 100.0 Soybeans Bran Paris green Oil. SAE 20-30 2 70 127.0 1936 Bluegrass, clover Bran Paris green Sodium pyro- arsenate Molasses and water 1 Molasses and water) 3 70 100.0 Bluegrass, clover Bran Paris green Oil, SAE 20 | Sodium pyro- Oil, SAE 20 1 3 70 113.0 Clover Bran and Liquid sodium sawdust arsenite Water 1 90.0 99.2 Clover, alfalfa Bran Paris green Lubricating oils) Sodium pyro- [ 6 87.5 96.3 arsenate Lubricating oils) 1937 Roadside Bran Sodium arsenite.. Molasses and water 2 92.5 101.8 Field and laboratory . . . Bran Paris green Lubricating oils White arsenic . . . Lubricating oils Crude arsenic . . . Lubricating oils 27 89.3 98.5 Sodium pyro- arsenate Lubricating oils Field and laboratory. . . Bran and ground cobs .... Paris green Crude arsenic . . . Oil. SAE 20\ Oil, SAE 20/ 4 93.5 104.5 Weed border Bran Sodium arsenite.. Oil, SAE 20 12 60. Ob 66.0 No actual count, estimated from observation. b This series of tests was made on an area infested with newly hatched grasshoppers, where re- placement was constantly occurring. 420 BULLETIN No. 442 The 1937 observations indicate that oils that are to be used in combined armyworm and cutworm bait should be of a quality marketed as commercial lubricating oil with a viscosity rating of SAE 20 to 30. OIL BAITS FOR GRASSHOPPER CONTROL For the control of grasshoppers, baits containing lubricating oils proved as effective as baits containing molasses and water or water alone (Table 3). The quality of the lubricating oil is, however, an important factor in its effectiveness. Oils that should not be used are: crankcase oil; reclaimed crankcase oil; fuel oils; oils of SAE 10 or less, which are in the class of floor oils; oils with a high sulfur content, and oils having a pronounced odor. The following oil-bait formula was successfully used by several thousand Illinois farmers: Base (bran, or bran and ground corncobs in equal parts) 100 pounds Poison (white arsenic or other poisons, see page 417) 4 pounds Lubricating oil, SAE 20-30 2 gallons Advantages of oil baits for grasshopper control 1. Control is satisfactory. 2. Materials are available everywhere. 3. The materials or the prepared bait can be stored over long periods. 4. Properly applied, these baits are not so likely to cause injury to tender crops as are other kinds of bait. Disadvantages of oil baits for grasshopper control 1. Cost per pound is slightly higher. 2. An oil may be obtained that is not satisfactory. 15,0504-3814137 DIVERSITY OF ILLINOIS-URBANA Q630.7IL6B C002 BULLETIN URBANA 433.444 1937-38 30112019529277 ' ; >: . ' : ; ' * -i'l -'. ' }' i--'t M 1 v ; '". ; ''" f , . ! i i - ''-;;; lilSHW!? HmHV' ;:^! <> '^"'V,' ^ : HHB8BBI