Budworm, tobacco

Pests and Insecticides. The most destmctive pests of the cotton plant are the boU weevil and the boUworm/budworm complex. They are serious threats to the cotton industry in countries around the world. The boU weevil migrated from Mexico around 1892 and spread over the entire cotton belt within 30 years. The domestic cotton crop lost to the weevil is worth 200 million a year. In addition, about 75 million a year is spent for pesticides to control this destmctive pest (8). Unfortunately, some insecticides used to control the weevil kill many beneficial insects. Among the undesired casualties are insects that help to control the boUworm and the tobacco budworm, pests that cause another 200 million loss in cotton. 

The continuing use of pyrethroids in agriculture has led to the emergence of resistant strains of pests. One of the best-studied examples is the tobacco budworm (Heliothis virescens), a very serious pest of cotton in the southern United States (McCaffery... 

Cotton Monsanto/1994 CrylAc protein Bacillus thuringiensis subsp. kurstaki (Btk) Resistance to cotton boUworm, pink boUworm and tobacco budworm... 

Endrin was introduced in the United States in 1951 as an avicide, rodenticide and insecticide. Its principal use to control the cotton bollworm and tobacco budworm peaked in the early 1970s. In 1979, the EPA canceled some uses of endrin and indicated its intent to cancel all uses of endrin (EPA 1979f USDA 1995). By 1986, all uses were voluntarily canceled (Bishop 1984, 1985, 1986 EPA 1993e USDA 1995), except for its use as a toxicant on bird perches, which was canceled in 1991 (USDA 1995). Endrin also was a contaminant in dieldrin (Verschueren 1983) however, all uses of this pesticide have been canceled since the mid-1980s (EPA 1992b). Consequently, there are no longer any significant releases of endrin to the environment in the United States. 

Several species of lepidopterous larvae cause bollworm-type injury to bolls and squares throughout the tropics. They include the bollworm [Heliothis armigera (Hbn.)], the tobacco budworm [Heliothis virescens (F.)], the black bollworm (Pro-denia latisfascia Wlk.), and in Peru Mescinia peruella Schaus. 

Polles, S.G. and Vinson, S.B. Effect of droplet size on persistence of malathion and comparison of toxicity of ULF and EC malathion to tobacco budworm larvae, / Econ. EntomoL, 62 89-94, 1969. 

Cuts from the silica gel column were incorporated into artificial diets optimized for several economically-important agricultural pest insects, the pink bollworm Pectinophora gossypiella> the tobacco budworm Heliothis virescens> the corn earworm H. zea and the fall armyworm Spodoptera frugiperda. > Monitoring with this artificial diet bioassay, further column chromatography and preparative TLC on silica gel in diethylether-petrol yielded five... 

Cuticular diterpenes-duvanes and labdanes. Cutler have found that the cuticular diterpenes of green tobacco have both allelopathic and insect-deterrent effects (38). Present in the cuticle are duvane and/or labdane diterpenes (Figure 3) The levels of these specific cuticular components are believed to be responsible for the observed resistance of some types of tobacco to green peach aphids Myzus persicae (Sulzer), tobacco budworm Heliothis virescens (F.), and tobacco hornworm Manduca sexta (L.) (39). 

Gossypium sp. Cyanidin-3-glucoside (anthocyanin) Tobacco budworm. 5, 363... 

Hedin, P.A. et al.. Multiple factors in cotton contributing to resistance to the tobacco budworm Heliothis virescens F., in Plant Resistance to Insects, Heden, P.A., Ed., American Chemical Society, Washington, 1983, 347. 

Hedin, P.A., Jenkins, J.N., and Parrott, W.L., Evaluation of flavonoids in Gossypium arboreum (L.) cottons as potential source of resistance to tobacco budworm, J. Chem. Ecol, 18, 105, 1992. 

The effects of selected fatty acid (Cio-Cia) methyl esters on the pink bollworm (Pectinophora qossypiella). bollworm (Heliothis zea) and tobacco budworm (Heliothis virescens) were determined, and a number of cyclopropyl, olefinic and acetylenic methyl esters were also tested (115). Methyl (Z,Z)-deca-2,8-diene-4,6-diynoate (matricaria ester) was lethal at low concentrations to all three insects. This last ester was isolated from Conyza canadensis but is found in vegetative matter of many plants of the Asteraceae. 

It was toxic to the pink bollworm at 0.005% and to the bollworm and the tobacco budworm at 0.15% in artificial diets. Esters (C10-C12) were also toxic to the insects as sprays. Matricaria ester was also shown to be a potent insect antifeedant compound to these insects (115). 

Most acetylenic compounds in plants are derived from meta-bolically altered fatty acids. These often are active in plant-insect relationships. 8-cis-Dihydromatricaria acid is also found in the defensive secretion of the soldier beetle (Chaulioqnathus 1econtei) (125), and has subsequently been shown to have anti-feedant properties against Phidippus spp. (jumping spiders) (126). As previously mentioned matricaria ester has antifeedant properties to the pink bollworm, bollworm and tobacco budworm (115). 

Multiple Factors in Cotton Contributing to Resistance to the Tobacco Budworm, Heliothis virescens F. 

Subsequently, a series of Investigations by a group at the Western Regional Research Center In California and associates have shown condensed cotton tannin to be an antibiotic chemical for the bollworm, tobacco budworm, and pink bollworm (13, 14,... 

Shaver and Parrott (17) reared bollworm and tobacco budworm larvae on a standard larval diet, and transferred them at 5 ages onto media containing 0-0.4% gossypol. The Influence on development Increased with larval age at the time of transfer. Recently Wales and his co-workers (18) Incorporated condensed tannin In diets fed to the tobacco budworm where the larvae Initially were of different ages. The ED5Q values were as follows 1 day,... 

Different lines, each with Insect resistance, may possess different ratios of antibiotic compounds. Thus, It may be possible to Increase resistance by crossing lines where each contributes genes for biosynthesis of different antibiotic compounds. The tobacco budworm was selected for study In preference to the cotton bollworm because It Is easier to rear and use In the laboratory, Is more resistant to Insecticides In the field, and It Is approximately as susceptible to cotton constituents Incorporated In laboratory diets (14). This present study was carried out to Identify and analyze for cotton constituents that were toxic In laboratory feeding tests, and to determine whether there were positive correlations of their content In leaves and/or other tissue with field resistance. From this Information, the generation of lines with multiple factors for resistance could be Initiated. 

First instar tobacco budworm larvae were restrained in 15 cm long dialysis casings that were slipped over the terminals, and collected and weighed after five days. Adequate numbers and replications were employed for statistical evaluation. 

Inhibition of Tobacco Budworm Larval Growth by Cotton Constituents BD5Q as Percent of Diet ... 

Figure 2. Percent gossypol in cotton terminal leaves and ranked tobacco budworm larval weights for 20 strains (r = 0,3771)-...

Relative Effects of Cotton Flower Petal Constituents on Tobacco Budworm Growth and Survival /... 

Average tobacco budworm weight after feeding 5 days on petals, e/ Not fed. 

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