A greenhouse seedling-selection technique was developed for mass screening seedling cotton, Gossypium sp., for resistance to Tetranychus urticae Koch. The salient procedures were mass rearing the two spotted spider mite on bean cotyledons for a constant source of mites, standardized greenhouse manipulation of plants, a plant-damage index for rating mite injury, and use of a standard variety for comparison of varietal resistance. The greenhouse seedling rating agreed with field rating and required Jess time (30 vs. 60 days). Fecundity was not a reliable indicator of resistance.
When quercetin, rutin, tannin, and gossypol were mixed in artificial adult and larval diets and fed to boll weevils, Anthonomus grandis Boheman, gossypol at 1.65 and 2.65% dry weight in the adult diet plugs caused a statistically significant increase in feeding, and levels of 1.15–2.15% significantly increased oviposition. Feeding was also increased at all other levels though not significantly beyond the base level of 0.15%. Gossypol, incorporated into larval diets in concentrations of 2.0–3.5%, significantly reduced the weight of emerging weevils, but 3.5% was required before the production of adults was significantly reduced. Quercetin did not significantly reduce feeding or oviposition. At levels of 0.1–0.6%, it increased the weight of emerging weevils, but at all other levels weight was not significantly affected. Tannin and rutin at levels of 0–1.0% did not significantly increase or decrease feeding. Tannin reduced weevil weight significantly at 0.2, 0.6, 0.8, and 1.0% levels; rutin at levels of 0.1–1.0% did not influence the weights of adult weevils at eclosion.
Journal Article Frego Bract Cotton and Normal Bract Cotton: How Morphology Affects Control of Boll Weevils by Insecticides Get access William L. Parrott, William L. Parrott Agricultural Research Service, USDA, State College, Mississippi 39762 Search for other works by this author on: Oxford Academic PubMed Google Scholar Johnie N. Jenkins, Johnie N. Jenkins Agricultural Research Service, USDA, State College, Mississippi 39762 Search for other works by this author on: Oxford Academic PubMed Google Scholar David B. Smith David B. Smith Agricultural Research Service, USDA, State College, Mississippi 39762 Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 66, Issue 1, 1 February 1973, Pages 222–225, https://doi.org/10.1093/jee/66.1.222 Published: 01 February 1973 Article history Received: 17 July 1972 Published: 01 February 1973
Journal Article Distribution of Tobacco Budworm (Lepidoptera: Noctuidae) Larvae Within Cotton Plants Get access F. S. Ramalho, F. S. Ramalho Search for other works by this author on: Oxford Academic PubMed Google Scholar J. C. McCarty, Jr., J. C. McCarty, Jr. Search for other works by this author on: Oxford Academic PubMed Google Scholar J. N. Jenkins, J. N. Jenkins Search for other works by this author on: Oxford Academic PubMed Google Scholar W. L. Parrott W. L. Parrott Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 77, Issue 3, 1 June 1984, Pages 591–594, https://doi.org/10.1093/jee/77.3.591 Published: 01 June 1984 Article history Received: 28 November 1983 Accepted: 09 February 1984 Published: 01 June 1984
We eliminated the microsporidian Glugea gasti McLaughlin from genetic stocks of the boll weevil, Anthonomus grandis Boheman, capitalizing on the fact that the disease is not transmitted by males, although the gonads are infected. We crossed diseased, mutant males with healthy, wild-type females and recovered the healthy mutants in the F2 generation. Techniques designed to eliminate the disease and to insure recovery of healthy mutants in the F2 generation were superimposed on the genetic procedure. The method is applicable to diseases of other insects in which one sex does not transmit the disease during mating.
Journal Article Effect of Dyes on Body Fat and Eye Color of Ebony Pearl Boll Weevils Get access Jack C. McGarty, Jr., Jack C. McGarty, Jr. Boll Weevil Research Laboratory, Agr. Res. Serv., USDA, State College, Mississippi 39762 Search for other works by this author on: Oxford Academic PubMed Google Scholar Johnie N. Jenkins, Johnie N. Jenkins Boll Weevil Research Laboratory, Agr. Res. Serv., USDA, State College, Mississippi 39762 Search for other works by this author on: Oxford Academic PubMed Google Scholar W. L. Parrott, W. L. Parrott Boll Weevil Research Laboratory, Agr. Res. Serv., USDA, State College, Mississippi 39762 Search for other works by this author on: Oxford Academic PubMed Google Scholar T. B. Davich T. B. Davich Boll Weevil Research Laboratory, Agr. Res. Serv., USDA, State College, Mississippi 39762 Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 65, Issue 2, 1 April 1972, Pages 370–372, https://doi.org/10.1093/jee/65.2.370 Published: 01 April 1972 Article history Received: 03 May 1971 Published: 01 April 1972
Entomologists and plant breeders have noted that glandless lines of cotton generally are susceptible to phytophagous insects. Gossypol, the yellow pigment present in the glands, has been shown to be the most important allelochemical that provides resistance. In field tests, high gossypol lines have repeatedly been correlated with lessened insect damage, probably due to toxicity of gossypol to Heliothis sp. and other cotton insects. Recent behavioral-histochemical studies of newly hatched larvae of tobacco budworm, Heliothis virescens (F), feeding on cotton showed that first-stage larvae avoided consuming the glands. However, when these molt between 48 and 72 h of age, they nonselectively consume the glands, suggesting a metabolic adaptation. Young tobacco budworm larvae prefer to feed along the margin area of the calyx crown of the square, an area devoid of gossypol glands. On resistant lines having glands in the calyx crown, the larvae feed sporadically on the tissue thus avoiding the glands. The numbers of gossypol glands on bracts of small squares, calyx crown, bract mid-rib, and the entire calyx differed significantly between the susceptible and resistant lines. First instar larvae placed on squares of cotton genotypes with high gland density in the small square bract and in the calyx crown, were significantly smaller than larvae placed on line with fewer glands. These and related studies suggest that breeding strategies should concentrate on placing gossypol glands in the calyx crown, the primary site of insect attack.
In 1970 four farms located in different parts of Mississippi each were planted to 4 to 8 ha of cotton ( Gossypium hirsutum L.), homozygous for frego bract ( fg fg ), and to an approximately equivalent acreage of a nonfrego commercial variety. Cottons with frego bract have shown resistance to boll weevils ( Anthonomus grandis Boh.) when grown in small plots. Our 1970 tests were designed to measure the cumulative effects of a fregobract cotton, designated M‐64, on boll weevil populations when this cotton was grown in large acreages and when the resistance was measured over three or four insect generations. Results from these tests will be used to assess the role of cottons resistant to boll weevil in an integrated approach designed to eradicate this insect. A pilot scale boll weevil eradication program is now underway in Mississippi. In the frego‐bract cotton boll weevil oviposition, an indirect measure of population, was suppressed 66, 71, 75, and 94% below that in the nonfrego varieties. The variation in suppression was due to different numbers of overwintering weevils and to various control measures used during the season. On two farms no insecticides were required for boll weevil control in the frego‐bract strain. The frego‐bract strain suppressed the population 94% on the farm with the smallest number of overwintering weevils. Thus, oviposition suppression was greatest where it can be of the most use in an eradication program. Fiber properties and yields of the frego strain were adequate for a nonbiased test of the boll weevil resistance attributed to frego bract.
