'^^ARD 
 
 September 1942 
 
 E-578 
 
 BAITS AND TRAPS FOR THE CONTROL OF TOBACCO AND TOMATO HORNWORMS 
 
 By L. B. Scott and Joe Milam, Division of Truck Crop and 
 Garden Insect Investigations 
 
 Introduction 
 
 For many years the larvae of the tobacco and tomato hornworm moths 
 (Pr otoparce sexta (Johan.)) and (P. guinqiiemaculata (Haw.)) have been known 
 as important pests of tobacco in many parts of the tobacco-growing sections 
 of the United States. These hornworms are also important pests of tomatoes. 
 
 Hornworms injure tobacco by devouring large portions of the leaves. 
 The damaged leaves may be ruined for commercial purposes, or in case of 
 moderately light feeding the quality, grade, and appearance of injured 
 leaves are lowered. Where abundant, the hornworms sometimes defoliate the 
 tobacco plants. In Tennessee, Kentucky, Virginia, North Carolina. South 
 Carolina, Georgia, and Florida, where hornworms on tobacco are regularly 
 or periodically abundant, it has been estimated that damage by hornworms 
 reduces the weight of the potentially marketable crop approximately 5 per- 
 cent annually, on an average. For the lO-year period 1929-38 the annual 
 farm value of the tobacco crop in these States was approximately $182,000,000. 
 A direct loss of 5 percent in the potential weight and value of this crop 
 because of hornworm damage amounts to approximately $9,600,000 a year. 
 This sum does not include the damage caused from reduction in quality, grade, 
 and general appearance in the cured product of tobacco injured by horn- 
 worms. The losses from these causes are estimated to be at least equal to 
 the losses suffered from reduction in weight. In addition, it is estimated 
 that the cost of control operations against hornworms on tobacco, principally 
 by applying insecticides and by hand picking, entails an annual expenditure 
 of at least $1,000,000. 
 
 On tomatoes the hornworms feed on the fruit, as well as on the 
 leaves, and cause extensive losses in some tomato-growing regions. No 
 figures are available regarding the extent of such losses. 
 
In searching for methods of controlling these hornworms on tobacco 
 in such a manner as to avoid the presence on the cured product of poisonous 
 cr otherwise objectionable residues incurred by the use of available insec- 
 ticides, extensive experiments have been performed in an attempt to deter- 
 mine the efficiency of baiting and trapping the parent moths of the horn- 
 worms, thus preventing them from laying their eggs on the plants. 
 
 Description of Baiting and Trapping Methods 
 
 The bait ordinarily used to attract hornworm moths is isoamyl salicy- 
 late, a chemical with a penetrating and pleasant odor. This chemical is 
 placed inside an assembly known as a "feeder" (shown in figures 1 to 4, 
 inclusive) . The feeder consists of a slip-cover can 5-3/8 inches in diameter 
 and 3 inches deep. It is painted medium dark green. In the center of the 
 top of the can is inserted a 1-inch vial filled with isoamyl salicylate, 
 provided with a loosely fitting cork and with a short length of wick which 
 permits the odor of the chemical to escape. Inserted equidistantly around 
 this vial in the top of the feeder, as shown in the illustrations, are 
 three small white funnels made of tin and shaped to resemble blossoms 
 of j imsonweed (D atura stramonium L. ) . The color and shape of these blossoms 
 are imitated for this purpose because hornworm moths are attracted to and 
 feed in large numbers on the blossoms of this plant. The apex of each of 
 the funnels extends downward into and nearly to the bottom of the feeder. 
 The feeder is filled with a poisoned liquid consisting of a sweetened solu- 
 tion containing 5 percent of tartar emetic. The holes at the apex of each 
 of the funnels permit the poisoned liquid to enter the funnels. 
 
 The assembled feeders may be used with or without a screen wire hous- 
 ing, or trap. When the latter is used, two of the feeders are placed in- 
 side the trap in the manner illustrated in figure 1 to 4. inclusive. The 
 number and location of traps for best results has not yet been determined. 
 The hornworm moths are apparently attracted to the near vicinity of the trap 
 by the escaping odor of isoamyl salicylate and are then visually attracted 
 by the white funnels simulating j imsonweed blossoms. After entering the 
 trap the moths feed on the poisoned liquid in the funnels and are retained 
 within the trap until they die. When the feeders are used without a trap 
 they may be placed at a height of approximately 5 or 6 feet, on the tops of 
 posts. The disadvantage of using feeders alone, as compared with feeders 
 inside the traps, is that when feeders are used alone the hornworm moths may 
 deposit eggs on the tobacco plants after partaking of the poison and be- 
 fore they die, whereas when traps are used the moths are confined until 
 they die. 
 
 Construction of Traps 
 
 The most satisfactory type of hornworm moth trap developed thus 
 for is illustrated in figures 1 to 4. inclusive. This trap is 36" long. 
 34" high, and 24" wide, and is constructed of 3/4" x 1-5/8" wood strips 
 
- 3 
 
 fastened at the corners by means of corrugated fasteners and 2-1/2" x 1/2" 
 flat corner irons. With these strips 5 rectangular sections are made to 
 form the framework of the top 24" x 36", the two sides 33" x 36" each, and 
 the two ends 22|" x 33" each. Each end has one cross piece 19^" long locat- 
 ed 20" from the bottom. These sections are assembled by fastening the sides 
 and ends together with 2" round-headed wood screws, the corners being streng- 
 thened by angle braces. The top is hinged to the upper edge of one of the 
 sides. The baffle (figs. 1, 2, and 3, A), which hangs in the center of 
 the trap, is made of l/2"-mesh hardware cloth and is 19" long by 15" wide. 
 It is supported by No. 9 wire, so formed that the baffle hangs 5" below 
 the top of the trap, 4" from each side, and 12" from the ground. The wire 
 support is formed into hooks which fasten to screw eyes on the sides of 
 the trap (fig. 3) . 
 
 The top, the two sides, and the part of each end above the cross- 
 piece are covered with galvanized-iron screening having 12 meshes to the 
 linear inch. The lower part of each end is also covered with this material 
 cut and shaped so as to form a large funnel converging inward for a distance 
 of 8" to ^orm a circular opening 7" in diameter to serve as an entrance for 
 moths. This entrance is formed on a 7" steel ring around which the screen 
 wire is folded and soldered to itself. The large outer opening of the fun- 
 nel is 20" high and 19:^" wide and is tacked to the inside faces of the 
 lower part of the end section. The distance along the screen from the outer 
 opening to the inner opening is 8" at the bottom, 9" at the sides, and 10" 
 at the top. 
 
 Two feeders (figs. 1, 2, and 3, B) are supported by a cross member 
 (figs. 1, 2, and 3, C) of 3/4" x 3" lumber resting edgewise, 1 inch from the 
 ground, on small wooden brackets (figs. 2 and 3, D) fastened centrally to 
 the bottoms of the inner faces of the two end sections of the trap. Each 
 feeder is held in position by means of two strips of galvanized band iron, 
 7" long and 1|" wide, fastened to the upper edge of the 3/4" x 3" support 
 with a 1-1/2" round-headed wood screw. The screw passes through 3/16" holes 
 in the centers of the iron strips and is tightened sufficiently to hold 
 them at right angles to each other. These metal strips are upturned at 
 the ends approximately 5/8" in order to hold the feeders in position. The 
 feeder is so placed that the top of the green can is in the same horizontal 
 plane as the bottom of the round inner opening (figs. 1 and 2, F) of the 
 entrance funnel and is spaced 5" from it. Thus the small, white, blossom- 
 like funnels of the feeders may be seen clearly by moths entering the trap. 
 
- 4 - 
 
 Materials and cost of one trap (fig. 4) and its feeders are as 
 follows: 
 
 Trap: 
 
 60 linear feet of 3/4" x 1-5/8" lumber $1.00 
 
 3 linear feet of 3/4" x 3" lumber 06 
 
 50 square feet of 12-mesh wire screen 1.50 
 
 2 square feet of |-"-mesh hardware cloth 10 
 
 30 inches of #9 steel wire 03 
 
 14 inches of l-^-" band iron 04 
 
 1 hook and eye 02 
 
 2 screw eyes 01 
 
 20 2i" X ^" flat angle irons with screws 30 
 
 4 angle braces with screws 08 
 
 8 2" round-headed wood screws 02 
 
 2 l-g-" round-headed wood screws 01 
 
 Paint 15 
 
 Feeders (2): 
 
 2 5-3/8" X 3" slip-cover cans 16 
 
 60 square inches of light-gauge sheet tin 15 
 
 2 1" vials 04 
 
 2 #2 lamp wicks 02 
 
 2 corks 02 
 
 Paint ^01 
 
 $3.72 
 
 The labor of one man for approximately one day is required to con- 
 struct a trap and its feeders. 
 
 Construction of Entrance Funnels 
 
 The screen-wire funnels are made from patterns shown in guide books 
 published for tinsmiths and sheet-metal workers. Books of this kind are 
 available at mail-order houses or they may be obtained through any large 
 book supply house. A pattern for a cone having rectangular base and round 
 top should be used. 
 
 Trap Coloration 
 
 The results of tests with traps painted various colors do not show 
 conclusively that coloration is an important factor in determining the 
 effectiveness of a trap, although there can be little question that white 
 traps are considerably less attractive than those painted green, red, yellow, 
 brown, or black. Traps painted medium brown appeared to be somewhat more 
 effective than those painted bright yellow, shutter green, bright red, or 
 black, but this was not shown conclusively. It is suggested that traps be 
 painted medium brown. 
 
- 5 - 
 
 Baiting and Trapping for Hornworm Control 
 
 Although the baiting and trapping of hornworm moths has not as yet 
 progressed to a point where its use results in an entirely satisfactory 
 control of these pests, this method is being improved upon each year, and 
 on the basis of available data there is reason to believe that it can be 
 used to advantage in many localities, especially where the infestation is 
 light or moderate. It has already been demonstrated that in areas .of light 
 infestation the damage by hornworms can be decreased materially by the use 
 of baits and traps and that the employment of this equipment permits a 
 marked reduction in quantities of insecticides otherwise required to prevent 
 serious losses to tobacco from the feeding of hornworms. The hazard of 
 insecticidal residue is also reduced by this method. 
 
 Small-scale tests conducted in 1941 in an area of very light horn- 
 worm infestation indicated that 10 feeders filled with sweetened bait con- 
 taining 5 percent of tartar emetic, placed at regular intervals on the 
 borders of a 3-acre field, or 4 traps similarly placed around a l-|-acre 
 field, were sufficiently effective to obviate the necessity of applying 
 insecticides. All other tobacco in the vicinity required the collection 
 of the hornworms by hand or the application of insecticides to protect it 
 from serious hornworm damage. Weekly examinations of 100 tobacco plants 
 taken at random in each of the fields where the feeders or traps were used, 
 as compared with similar examinations in two comparable fields where the 
 feeders or traps were not used, indicated that the traps and feeders were 
 very effective in protecting the plants from damage. The data obtained 
 from these fields, which indicate that serious hornworm damage may be 
 avoided in areas of light infestation, are summarized in table 1. No conclu- 
 sive data are available at this time to show the extent of protection af- 
 forded to the tobacco crop by the use of baits or traps. 
 
 Table 1. — Results from the use of baited traps in tobacco fields for horn- 
 worm control 
 
 Field 
 
 
 I 
 
 1 Numbe 
 
 r of 
 
 Plants 
 
 |Eggs 
 
 Larvae 
 
 1 Other 
 
 No. 
 
 Acres 
 
 Treatment 
 
 observations 
 
 examined 
 
 1 found 
 
 found 
 
 j treatment 
 
 1 
 
 3.0 
 
 10 feeders 
 
 
 6 
 
 600 
 
 13 
 
 90 
 
 None 
 
 2 
 
 1.5 
 
 4 traps 
 
 
 5 4/ 
 
 500 
 
 25 
 
 89 
 
 None 
 
 3 
 
 1.5 
 
 Check 
 
 
 6 
 
 600 
 
 29 
 
 330 
 
 Hand-wormed 
 every day 
 
 4 
 
 2.1 
 
 Check 
 
 
 6 
 
 600 
 
 103 
 
 184 
 
 Two applications 
 of lead arsenate; 
 
 
 
 
 
 
 
 
 
 hand-wormed once 
 
 4/ Crop harvested prior to sixth observation, 
 
6 - 
 
 Tobacco growers should not expect to obtain complete control of 
 hornworms by the use of baits and traps in areas of heavy infestation, but 
 it is believed that the use of this control method will reduce the infes- 
 tation, lessen the damage from hornworms, and permit the grower to use 
 smaller quantities of insecticide than would otherwise be necessary. 
 
±1 
 
 \L 
 
 Figure 1. — Side view of horaworm moth trap. A, beiffle; 
 B, feeder, G, feeder 8iq>port; E» entrance funnel; F, 
 round Inner opening of entrance funnel. 
 
Figure 1. — Side view of homworm moth trap. A, baffle; 
 B, feeder, C, feeder 8iq>port; E, entrance funnel; F, 
 round inner opening of entrance funnel. 
 
Digitized by the Internet Archive 
 in 2013 
 
 http://archive.org/details/baitstrapsforconOOunit 
 
Figure 2. — Top view of homworm moth trap. A, baffle; 
 
 B, feeder; C, feeder siipport; D, bracket for feeder 
 
 siipport; E, entrance funnel; F, round inner opening 
 of entrance funnel* 
 
r7nr7 
 
 /B 
 
 I n 
 
 II 
 
 jC 
 
 30" 
 
 34^" 
 
 Figure 3. — Details of the construction of the feeders, 
 feeder support, and baffle; A, baffle; B, feeder; 
 C, feeder support; D, bracket for feeder siqjport. 
 
Figure 4-« — View of assembled hornworm trap. Photograph 
 made from a miniatiire model approximately one-third 
 the size of the trap used in field tests. 
 
UNIVERSITY OF FLORIDA 
 
 3 1262 09230 3725