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Anthonomus grandis grandis Boheman, sterilized by being fed a diet containing 100 ppm of diflubenzuron for 5 days after emergence followed by 10 krad of irradiation, were tested in 0.8-ha plots in two locations. In south Mississippi, where a few native weevils were present and the plots were infested by releasing overwintered adults, egg hatch was reduced but there was no reduction in infestation or weevil captures. In Arkansas, where no native weevils were present and the plots were infested by allowing weevils to emerge from squares, there were significant differences in egg hatch, infestation levels, and weevil captures. These data show the potential of sterile boll weevils in an eradication or management program.

During the period 1955–1973, winter survival of the boll weevil, Anthonoumus grandis Boheman in Mississippi, as determined by examination of surface woods trash samples in the fall and sprrig, ranged from 0.2 to 51.6% for a state avg. The numbers of weevils entering hibernation in the fall ranged from 0 to 72,149/ha. In most years percentage survival was greater at the southern end of the study than at the northern end. Several climatic factors (minimum temperature, number of days during which the minimum temperature was O°C or below, number of days during which the maximum temperature was O°C or below) were correlated with survival percentage.

In the spring of 1969, male-baited traps for Anthonomus grandis Boheman were placed around ca. 4000 acres of cotton in a large-scale field test in Monroe County, after completion of a voluntary grower-sponsored reproduction-diapause control program the fall of 1968. The few fields that had not been treated produced a population of weevils which varied from field to field. Where over wintered boll weevils numbered less than 5 per acre, the trap efficiency was estimated to be 93%, but it dropped to 21% when the populations averaged about 300 weevils/acre. Differences in the number of over wintered boll weevils collected per trap were not significant when 1, 2, 4, and 8 traps per acre were compared. However, significantly more over wintered boll weevils were found in the fields with 8 traps per acre than in fields with 2 traps per acre. Inter field movement of over wintered weevils from the fields that had not been treated appeared to be restricted to those fields that shared over wintering sites with the untreated fields. Some fields were treated with insecticides in July for control of 1st-generation boll weevils, but many fields did not require treatment until early August.

In 1960-61, tests were conducted in 3 cottonfields located on Mississippi to study the relationship between plant fruiting and the first entry of boll weevils, Anthonomus grandis Boheman, into diapause. Tests were set up also to evaluate the effectiveness of methyl parathion in controlling diapausing weevils and to measure population increases on dryland cotton. In the diapause studies, first diapausing weevils appeared in all 3 fields at cessation of flowering, when only bolls remained as the food source. In the diapause-control studies, 7 applications of methyl parathion spray applied at ½ lb/acre greatly reduced the overwintering population but did not eliminate it. In the limited studies of population dynamics, seasonal generation-to-generation increases averaged 5-fold and ranged from 1- to 9.6-fold.

In a 2-year replicated field-cage experiment with boll weevils, Anthonomus grandis Boheman, first-generation progeny from estimated overwintered populations of 0, 14, 25, 50, and 100 weevils per acre damaged 0, 28, 46, 66, and 83% of the squares, respectively. Second-generation weevils damaged from 84 to 96% (weevil-free check excluded) of the squares. Seed cotton harvested from the respective treatments averaged 2802, 1875, 1678, 1318, and 847 lb per acre. Differences in lint quality were detected between plots infested with 100 overwintered weevils per acre and those infested at the other 4 levels. These differences were observed in the first and third harvesting in 1961. No other quality differences were observed.

Azinphosmethyl applied as an ultra-low-volume spray at 0.2 and 0.25 lb per acre was as effective as a water-emulsion spray of methyl parathion (0.5 lb per acre) in a reproduction-diapause control experiment conducted in Carroll County, Mississippi, against the boll weevil, Anthonomus grandis Boheman. A lower rate of azinphosmethyl, 0.125 lb per acre, was less effective. Populations. of boll weevils sampled in woods trash adjoining treated and untreated fields were reduced 94% the fall of 1965 and 98% the spring of 1966.

During 1958 studies of the preferred feeding and egg-laying sites of the boll weevil ( Anthonomus grandis Boheman) were conducted at Stoneville, Miss. Females damaged the fruit of the cotton plant more than males. The preferred feeding and egg-laying sites were the squares on the upper half of the plants when the population was low. As the population increased, small bolls were damaged as well as squares; the damage was intensified on the upper portions of the plants and reached into the lower fruiting branches. Bolls from 1 to 19 days old were subject to weevil damage. Exposure of the cotton plant to feeding and egg laying by the boll weevil for 4 or 5 days resulted initially in increased square abscission and slightly reduced boll abscission. No difference occurred in total boll set for the entire season between the test and check plants.

In experiments at Stoneville, Mississippi, in 1957 and 1958 a Guthion-DDT mixture gave outstanding control of the boll weevil ( Anthonomus grandis Bah.). Sevin® (1-naphthyl methylearbamate), toxaphene-malathion, dieapthon, Bayer 29493 ( O,O -dimethyl O -(4-methylthio- m -tolyl) phosphorothioate), and mixtures of Monsanto CP 7769 (hexaethyl (ethylthioate ethylidyne) triphosphonate), methyl parathion, toxaphene, or malathion with DDT gave generally satisfactory control, but Thiodan® (6,7,8,9,10, 10-hexachloro-1, 5, 5a, 6, 9,9a-hexahydro-6, 9- methano-2,4,3-henzodioxa thiepin-3-oxide), runnel- DDT, toxaphene, and endrin were not effective. The mixture of DDT with runnel, Monsanto CP 7769, Guthion® ( O, O -dimethyl S -(4-oxo- 1,2,3-benzotriazin-3-(4 H )-ylmethyl) phosphorodithioate), methyl parathion, and malathion were effective in controlling the bollworm (Heliothis zea (Boddie)).

Good control of thrips ( Frankliniella spp.) was obtained with dimethoate, Di-Syston® ( O,O -diethyl S -[2-(ethylthio)ethyl] phosphorodithioate), and phorate granules applied in the furrow with the seed, and sprays of Shell SD-3562 (2-dimethylcarhamoyl-1-methylvinyl dimethyl phosphate), and mixtures of toxaphene, Strobane® (terpene chlorinates (65% chlorine)), and endrin with DDT. Good control of the tarnished plant bug ( Lygus lineolaris (Palisot de Beauvois)) was obtained with sprays of Bayer 25141 ( O,O -diethyl O-p -methylsulfinyl-phenyl phosphorothioate), Hercules 5727 ( m -isopropylphenyl methylcarbamate), Strobane DDT, Shell SD-4402 (1,2,3,4,5,6,7,8,8-octochloro-3a,4,7,7a-tetra- hydro-4,7-methanophthalan), Trithion® ( O,O -diethyl S-p -chloro-phenylthio-methyl phosphorodithioate), toxaphene-DDT, Methyl Trithion® ( O,O -dimethyl S-p -chlorophenylthiomethyl phosphorodithioate), Shell SD-5533 (dimethyl 1-( p -nitrobenzyloxycarbonyl)-1-propen-2-yl phosphate), Bayer 29493 ( O,O dimethyl O -]4-(methylthio)- m -tolyl] phosphorothioate), Sevin® (1-naphthyl N -methylcarbamate), Shell SD-3562,and Guthion® (italic> O,O -dimethyl S -(4-oxo-1,2,3-benzotriazin-3-(4H)-ylmethyl) phosphorodithioate)-DDT. Geigy 30494 ( O,O -dimethyl S -2,5-dichlorophenylmercaptomethyl phosphorodithioate), Methyl Trithion, Trithion, Sevin wettable powder, and mixtures of DDT with endrin, toxaphene, methyl parathion, Strobane, or Guthion all gave good control of the boll weevil ( Anthonomus grandis Boheman) and the boll worm ( Heliothis zea (Boddie.)) Phorate granules lind sprays of ethion, Trithion, Diazinon® ( O,O -diethyl O -(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate), Geigy 30494, and Shell SD-3562, Delnav® (a mixture of 2,3- p -dioxanedithiol S,S -bis ( O,O -diethyl phosphorodithioate) (70%) and related compounds), and methyl parathion at 0.5 pound per acre gave good control of a spider mite ( Tetranychus lobosus Boudreaux).

Results of studies of female Anthonomus grandis Boheman made to determine the influence of biological factors Oil its response to male sex pheromone indicated that: (1) laboratory-reared males were as attractive and females were as responsive as native weevils if they had access to cotton squares (flower buds) as food; (2) increased attraction of isolated males over grouped males was substantiated; (3) males in close proximity to females were no more attractive to females than isolated males; (4) the lack of response of recently mated females emphasized the need to capture females in traps before they mate with free, competing males; (5) sterilization of males with apholate or irradiation did not significantly decrease their attractiveness compared with untreated males: (6) females responded to males as many as 3 times and from distances of as much at 82 m; (7) the high percentage of females captured in traps baited with males in the absence of competing males, and the low percentage captured with males in traps in an infested plot containing large numbers of competing males suggest that the sex pheromone might have a major role in suppressing weevil populations in areas where populations are extremely low. for example, in the spring after an effective fall diapause-control program has substantially reduced the number of over wintering boll weevils.

From June 17 through August 26, 1964, 11 weekly releases of apholate-sterilized male boll weevils, Anthonomus grandis Boheman, were made in 9 cottonfields, (15.8 acres) that had been treated with insecticides the fall of 1963 to reduce the population of diapausing weevils. These weekly releases ranged from 3270 to 26,620 sterile weevils per acre (an average of 8200 per acre). Migrant weevils entering the release zone from other areas may have caused the program to achieve population suppression rather than eradication, though the release zone was surrounded by a 120-acre zone that had received the same fall treatment and was treated intensively with insecticides in 1964 and by another 115-acre buffer zone that was treated with insecticides in 1964. However, the apholate sterilized only an average 95.8% of the weevils and caused a substantial reduction in mating competitiveness. The release of the sterile males against the low-level population achieved by the 1963 fall applications reduced the number of oviposition-punctured squares compared with the number in the other 2 zones. Also the percentage of infertile eggs, the numbers of live immature and adult weevils per acre in fruit, the numbers of adults on plants and in hibernation sites, the numbers of overwintered adults, and the levels of infestation during the 2nd year or season after the releases were terminated were considerably lower in the release zone than in the zone treated intensively with insecticides.

The thirty-second annual meeting of the Cotton States Branch, E.H.A., was held in the Hotel Peabody, Memphis, Tennessee, on December 2, 3, 4, and 5, 1957. The meeting was heldin conjunction with the parent association of the Entomological Society of America. One hundred twenty-eight members and guests registered for the four-day meeting. Chairman Norman Allen opened the first of two branch business meetings promptly at 4:30 P.M. on December 2.

Over 600,000 mixed sex sterile Anthonomus grandis grandis Boheman that had been sterilized by feeding them diflubenzuron treated diet for 6 days and then irradiating them were released in 2.4 ha of cotton in south Florida. Results showed that a boll weevil population was not established in the field which indicated that all of the insects were sterilized.

In replicated small-plot field tests good control of thrips (primarily Frankliniella fusca (Hinds)) was obtained with sprays of Bayer 25141 ( O,O -diethyl O-p -methylsulfinylphenyl phosphorothioate), toxaphene +DDT, Shell SD-3562 (dimethyl 1-(dimethylcarbamoyl)-1-propen-2-yl-phosphate), endrin + Shell SD-3562, methyl parathion +DDT, methyl parathion + Shell SD-4402 (1,3,4,5,6,7,8,8-octachloro-3a,4,7,7a-tetrahydro-4, 7-methanophthalan), Bayer 29493 ( O,O -dimethyl O -[4-methylthio- m -tolyl] phosphorothioate), Geigy 30494 (S-(2-5-dichlorophenylmercapto) methyl O,O -dimethyl phosphorodithioate), Zectran® (4-dimethylamino-3,5-xylylmethylcarbamate), Guthion® ( O,O -dimethyl S -(4-oxo-1,2,3, benzotriazill-3-(4 H )-ylmethyl) phorodithioate) +DDT, Sevin® (1-naphthyl N -methylcarbamate), toxaphene, and Geigy 30493 ( S -(3,4-dichlorophenylthio)-methyl O,O -dimethyl phosphorodithioate). Better residual control was obtained with Bayer 25141, Shell SD-3562, and toxaphene +DDT than with the other materials in the test. The addition of Plyac (Polyethylene spreader-sticker) to sprays of toxaphene +DDT, Sevin, and Guthion +DDT did not improve the control or extend the residual activity of these materials against thrips. The application of toxaphene and Shell SD-3562 in the reemergence herbicide treatment failed to give any control of drips after the cotton came up. One application of Shell SD-3562 did not give as good season-long control as three applications at weekly intervals.

The resistance of several strains of cotton to the boll weevil, Anthonomus grandis Boheman, was studied for 4 years at Stoneville, Mississippi. Strains included were M-8, D2-Smooth, Pilose-Okra leaf, Nectariless, Glandless, Yugoslav-Early Upland, Red Plant, and Asiatic. The Asiatic strain was significantly more resistant than any of the others. Yugoslav Early had the earliest and greatest boll weevil infestation.D2-Smooth, Glandless, and Nectariless had intermediate infestations, all of the same level. Plant height, color, and growth characteristics were factors affecting the percentage of squares punctured.

In field experiments conducted in DeSoto County, Mississippi, in 1961-62, selected procedures were evaluated for effectiveness in preventing the boll weevil, Anthonomus grandis Boheman, from entering diapause. Methyl parathion spray (0.5 lb/acre) was applied at 7- to 9-day intervals in the fall of 1961, when the first boll weevils were found in diapause. A desiccant, pentachlorophenol, was used to terminate plant growth in mid-October. Control measures reduced both fall and spring weevil populations, but these reductions were not large enough to substantially reduce the number of insecticide applications needed for boll weevil control in the next crop season. Population pressure in September decreased effectiveness of methyl parathion in October, and an abundance of food (squares, flowers, and bolls) for surviving boll weevils in treated fields contributed to the less-than-desired effectiveness of the control program.

The residual toxicity of 3 phosphorous insecticides to the boll weevil, Anthonomus grandis Boheman, was determined hourly for 24-48 hours by using field cages made of ice cream cartons. The cages were an improvement over those formerly used and should facilitate such studies of similar chemicals and insects. Azinphosmethyl at 0.25 lb per acre was effective for 12-24 hours and at 0.5 lb per acre, for more than 24 hours. Methyl parathion at 0.25 and 0.5 lb per acre was effective for only 2-4 and 4-6 hours, respectively. Malathion at 0.5 lb per acre gave residual kill for 4-6 hours; at 2 lb per acre it was effective for more than 24 hours.

Initial entry into diapause by segments of populations of the boll weevil ( Anthonomus grandis Boheman) were studied in one field in 1958 and in seven fields in 1959. In the 1958 field diapause occurred by August 26. In the 1959 fields it was observed as early as August 11 and as late as September 8. Weevil populations generally entered diapause in two distinct periods. Gross observations indicated that entry into diapause in the first period was related to the maturity of the plants in the different fields, An adequate food supply appeared to be necessary. Diapausing weevils were first recovered from ground trash on September 10 in 1958 and September 9 in 1959, which indicated movement by diapausing segments of the weevil populations to overwintering quarters well in advance of the first killing frost.

The effect of four different levels of infestation by the boll Weevil ( Anthonomus grandis Boheman) on earliness, yield, and quality of cotton lint was evaluated in a replicated field-cage experiment at Stoneville, Mississippi, in 1959-60. Seasonal square (Hower-bud) infestation levels of about 0%, 25%, 50%, and 75% were used. As infestation level increased, plant fruiting was delayed, with a subsequent delay in time of harvest. Plots held at 0% infestation yielded the earliest cotton; those at the highest infestation level produced the latest harvestable cotton. Yield data indicated an inverse relationship between total yield and percentage of squares damaged throughout the season. Grade indexes and lint values indicated no significant loss in quality of lint at the different infestation levels. Differences in value of lint per acre for the four treatments actually reflected differences in yield.

Overwintered ♂ boll weevils, Anthonomus grandis Boheman, were found to produce only very small quantities of pheromone. Also, the ratio of the 4 components in the pheromone of these weevils differed from that in the standard formulation of grandlure and was less attractive. Consequently, even sterilized laboratory weevils should be more attractive than overwintered males.

In a 5-yr study in the hill area of Mississippi, boll weevils, Anthonomus grandis grandis Boheman, were captured every month of each year, except March 1974. The largest numbers were captured in Oct. and the smallest numbers in Mar. Totals captured from 1971 through 1975 were 8959, 3399, 2058, 1213, and 715, respectively. Averages captured per trap per month ranged from 0–164.3.

In-field traps were superior to other techniques for detecting very low populations of Anthonomus grandis Boheman in cotton fields. Five, 10, 15, 20, and 25 infield traps/ha were compared in an isolated cotton field in Arkansas. Only one punctured square and no live weevils were found in hand examinations during the experiment. No weevils or punctured squares were found with an insect collecting machine. A total of 25 overwintered weevils and 71 field generation weevils was captured with in-field traps from May 26-Sept, 7. Twenty-five traps/ha captured the majority of weevils caught during the test.