Cotton boll

While solid m.p. 95 -96 - C, soluble in organic solvents. An insecticide similar to chlordane. Used to control cotton boll weevil. 

Scheme 54 summarizes Font s synthesis of (+)-grandisol (36), the male pheromone of the cotton boll weevil (Anthonomus grandis) [80]. The key-step is the double [2+2] photocycloaddition of ethylene to bis(a,(3-butenohde) A to give B, which yielded C after glycol cleavage. The recently identified pheromone of the oleander scale (Aspidiotus nerii) possesses a structure similar to that of grandisol (Scheme 54), and its synthesis was reported by Ducrot [81 ] and also by Guerrero [82,83]. 

Koskinen, W.C., Leffler, H.R., Oliver, J.E., Kearney, P.C., and McWhorter, C.G. Effect oftrifluralin soil metabolites on cotton boll components and fiber and seed properties, J. Agric. Food Chem., 33(5) 958-961, 1985. 

Insecticidal control of the pink bollworm is yet another management practice used by growers in Arizona pink bollworm exit holes in cotton bolls might provide portals of entry for A. flavus (55). Unfortunately, it is not economically feasible to achieve 100% control of the pink bollworm in cotton through the hi -ftequency use of insecticides, and even relatively low levels of infestation by this insect pest is well correlated to high levels of A. flavus infection and subsequent aflatoxin contamination. 

Agricultural fields often harbor strains of A. flavus that produce little or no aflatoxin during invasion of cotton bolls these strains greatly reduced aflatoxin contamination when the bolls were co-inoculated with a toxigenic strains. Therefore, non-toxigenic strains are potential biocontrol agents. 

Figure 1. Phenological synchronization of cotton boll opening and diapause of boll weevils and bolhvorms (38).

The role of phytoecdysones in this scheme is that of an Important component in a rather complex defensive strategy of some plants. Their presence in plants probably serves a limited, yet important, protective role. For example, cotton bolls bred with several ppm of ponasterone A would very likely be resistant to attack by pink bollworm. 

Nonabsorbable Natural Sutures. Cotton and silk are the only nonabsorbable sutures made from natural fibers that are still available in the United States. Cotton suture is made from fibers harvested from various species of plants belonging to the genus Gossipium. The fiber is composed principally of cellulose. The seeds are separated from the cotton bolls, which are carded, combed, and spun into yams that are then braided or twisted to form sutures in a range of sizes (Table 4). The suture is bleached with hydrogen peroxide and subsequendy coated (finished or glaced) with starch and wax. The suture may be white or dyed blue with D C Blue No. 9. 

We all know of the old practice of "pickin cotton" - harvesting cotton bolls by hand. In general, this practice has been replaced by machine harvesters. Since introduction of the harvest machine, use of chemical aids has become common-place. Cotton leaves are defoliated by chemical harvest aids on more than 75% of the cotton acreage in the U.S. - representing more than 7 million acres of cotton. 

Historically cotton bolls have been harvested by hand. More recently, however, the development of machine harvesters has reduced production costs. For efficient use of both types of pickers (the spindle type with rotating spindles that picks the cotton only from open bolls, and the stripper type which strips... 

NuralA. H., Tittiger C., Welch W. and Blomquist G. J. (2001) Isolation and characterization of isoprenyl diphosphate synthase from cotton boll weevil. Presented at Annu. Meet. Int. Soc. Chem. Ecol. 18th, Lake Tahoe. 

Grandisol—the sex pheromone of the male cotton boll weevil... 

House-flies are irritating and a minor health hazard, but the cotton boll weevil is an enormously destructive pest of the American cotton crop and is responsible for vast economic losses. The weevil has a pheromone called grandisol. The structure and synthesis of grandisol are rather more complicated than the syntheses of muscalure, but all the reactions are ones you have met in the first 24 chapters of the book. 

The synthesis of grandisol(I) and lineatin(II) is discussed. Grandisol is a pheromone component in the cotton boll weevil and in Pissodes weevils. 

The plant material was extracted according to the procedure in Figure 1. The ethanol extract [2] (Figure 1) exhibited total inhibition of feeding against the cotton boll weevil at levels of 10, 25, and 50 mg (Table I). Further fractionation of the ethanol extract [2] showed no abatement of this antifeedant activity in either the CHClj [3] or the aqueous fraction [4] with %T/C values of less than 12% at the 10-50 mg dose levels as indicated in Table I. Further fractionation (Figure 1) and bioassay (Table I) showed that the methanol fraction [6], and the CHC /ethanol fraction [7] demonstrated excellent antifeedant activity. 

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