Cotton Boll Weevil An Evaluation of USDA Programs : a Report (1981) / Chapter Skim
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COTTON INSECT CONTROL
COTTON INSECT CONTROL
Pages 20-41
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From page 20... ...
The history of insecticide use on cotton insect pests can be divided into four periods, each of which is discussed below. The Arsenical Period The first insecticide recommended for control of the boll weevil was a spray utilizing Paris Green, London purple, or lead arsenate in combination with molasses (Townsend l895, Maley l902)
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From page 21... ...
Calcium arsenate also had an impact on the natural enemies of the cotton flea hopper and of lygus bugs, particularly in the Southwest and in newly irrigated areas of the West. Sulfur dusts were incorporated into control programs to deal with these pests as well as occasional outbreaks of red spider mites (Tetranychidae)
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From page 22... ...
These mixtures initially provided control of aphids, fleahoppers, plant bugs, leaf-feeding caterpillars, and spider mites as well as boll weevils, bollworms, and budworms. Growers demanded insecticidal mixtures that would produce cotton fields almost completely devoid of insects (Reynolds et al.
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c 530 (1970-Nicaragua) i Methyl parathion 23 (1970-Mississippi)
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From page 24... ...
. Overall Chemical Use It has been estimated several times that from 40 to 50 percent of all crop insecticides in the United States have been used to control cotton insect pests (Pimentel l973; USDA l965, l970, l974, l978)
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. 26 30 •alathion 1,811 559 670 43 213 245 273 55 methyl parathion 8,760 7,279 22,988 19,981 5,420 3,577 6,384 6,166 •onocrotophoa 1,487 1,494 parathion 1.636 2,181 2,560 680 7S1 MO 682 561 phorata 10 100 158 35 _ l82 U5 trichlorfon 963 144 512 191 .
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From page 26... ...
Yet, as Table 2.l shows, there is already evidence that the tobacco budworm has developed resistance to permethrin. The history of chemical control of cotton insect pests during this century suggests that its future is doubtful.
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From page 28... ...
Careful management of boll weevil control programs can reduce the insecticide load, and careful timing of insecticide applications can avoid the destruction of the beneficial insects that control Heliothis. What this means is using insecticides toward the end of the growing season to minimize the number of boll weevil adults leaving cotton fields to overwinter (diapause control)
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From page 29... ...
The traits that provide such resilience have been discovered in rare and isolated types of cotton and utilized to confer host plant resistance (HPR) against the major cotton insect pests, including the boll weevil, bollworm, tobacco budworm, pink bollworm, and Lygus species.
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From page 30... ...
. Furthermore, natural selection among cotton insect pests may negate host plant resistance.
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From page 31... ...
. The boll weevil populations in frego bract fields were one third as large as the populations in cotton fields of other types when no diapause program was applied to either the frego or non-frego fields and in-season treatments for weevils were applied as needed (Jenkins and Parrott l97l)
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From page 32... ...
Damage to frego bract strains from plant bugs (Lygus species) may be as much as twice as great as damage to normal bract strains (Jones l972)
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. Crossing glabrous and frego bract cotton with okra-leaf cotton partially reduced their susceptibility to plant bugs (Jones et al.
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From page 34... ...
Boll weevil-resistant varieties of cotton will not become a reality until breeders are able to combine traits that help cotton plants resist the boll weevil with genetic backgrounds that insure at least a normal level of resistance to other cotton insect pests. Red stem varieties of cotton with a minimum of negative traits will probably be commercially important in the near future, but frego bract's resistance to the boll weevil cannot be exploited until the variety's increased susceptibility to Lygus is overcome.
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From page 35... ...
Unlike the sex pheromones of a majority of the lepidoptera, which are produced by females, grandlure is elaborated by the male boll weevil in fecal pellets. Grandlure apparently functions as an aggregating pheromone during early spring and again during the fall, when boll weevil populations migrate.
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36 S € & M 8 X o 1 M pi £• i h 1 H a 1 I *
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From page 37... ...
Approximately l00 million sterile pink bollworm moths have been released annually in the San Joaquin Valley to prevent the establishment of this pest. In a similar program, sterile Mexican fruit flies have been released annually in southern California since l964, the purpose being to prevent the establishment of flies dispersing from Mexico.
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From page 38... ...
. Studies of the attraction of females to traps baited with sterile males have indicated that the attraction of females to both sterile males and grandlure is greatly reduced by the presence of normal males (Boll Weevil Research Laboratory l98la)
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From page 39... ...
In l980 an extensive test involving two methods for the dispersal of sterile weevils in a test and control area containing comparable weevil populations in North Carolina provided no clear findings (J.E. Wright, Mississippi State University, Mississippi State, MS, personal communication l98l; Boll Weevil Research Laboratory l98lc)
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From page 40... ...
Diflubenzuron has moderate persistence in biological systems. In a laboratory model ecosystem treated with diflubenzuron, the percentages of parent diflubenzuron found in the organisms after 30 days of exposure were alga, 46 to 6l; snail, 73 to 90; mosquito larva, 84 to 98; and fish, 5.2 to 6.7.
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From page 41... ...
After 33 days in the water phase of a laboratory model ecosystem, two radiolabeled preparations of diflubenzuron had 24 to 3l percent of the total extractable radioactivity present as the parent compound (Metcalf et al.
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