Genetic structure of Tribolium castaneum populations in mills

We investigated the genetic diversity and differentiation among nine populations of Tribolium castaneum using eight polymorphic loci, including microsatellites and other insertion-deletion polymorphisms (=”indels”). Samples were collected in food processing/storage facilities located in Kansas, Nebraska, California, Louisiana, Florida and Puerto Rico. Standard population genetic analysis was applied, and an assignment test was used to assign individuals to their genetic population. All loci were polymorphic across populations, with the number of alleles per locus-population combination varying from three to fourteen. Among 72 locus-by-population combinations, 31 deviated significantly from Hardy-Weinberg equilibrium, which was associated with a deficiency in heterozygosity. Tribolium castaneum populations show some level of genetic structuring. Genetic differentiation between populations, using FST estimates, was significant, with FST varying from 0.018 to 0.149. AMOVA indicated that 8.32% of the variation in allele frequency resulted from comparisons among populations. Genetic distance was not significantly correlated with geographic distance. Correct assignment to the genetic population was possible in only 56% of all individuals. Together, these results revealed that geographically distinct populations of T. castaneum had low to moderate levels of genetic differentiation that was not correlated with geographic distance, and the genotypic profile of the individuals did not provide enough information for fingerprinting them with their source population. Keywords: Tribolium castaneum, Population genetics, Genetic structure, FST, Genetic fingerprintin

Variegated Cutworm Control, 1985

Abstract This test was conducted at the Garden City Experiment Station in Finney County, KS. The plots were 4.6m by 4.6m in a randomized complete block design with 3 replications. The plots were treated on 31 May after the first cutting of hay was removed. The variegated cutworm larvae were approximately 2.5 cm long. The treatments were applied using a CO2 backpack sprayer with a 1.5-m boom calibrated to deliver 119 liters of spray per acre. Counts were made on Jun 1 by visually searching 2 strips of 0.3 m × 3.2 m across each plot for dead larvae.</jats:p

Fficacy of Miticides Against Corn Spider Mites, 1986

Abstract #1: This experiment was conducted in Finney County, KS in a field of sprinkler irrigated corn. Twelve treatments were arranged in a randomized complete block design with 4 replications. The plots were 4 rows × 10 ft, 50 ft long, and surrounded by 10 ft borders of untreated corn. Prior to treatment application, 4 plants in each plot were selected from the center 2 rows and flagged. Treatments were applied with a high clearance sprayer using a 10 ft boom with 3 nozzles directed at each row (1 nozzle directly over the row and one on each side of the row on 18 inch drop hoses). The sprayer was calibrated to deliver 20 gpa of water with 30 psi of CO2 pressure. Spider mite counts were made from the flagged plants by searching every other leaf (half plant sample) on each plant for large mites (primarily the adult females). Pretreatment counts were made on 23 Jul and 2 posttreatment counts were made on 8 and 14 Aug. Twospotted spider mites presence was determined by collecting 20 to 40 mites from the flagged plants using a small vacuum sampler and mounting them for microscopic determination of mite species.</jats:p

Efficacy of Miticides Against Corn Spider Mites, 1985

Abstract This experiment was conducted in furrow-irrigated corn planted at the Garden City Experiment Station in Finney County, KS. Fifteen treatments and a check were arranged in a randomized complete block design with 4 replications. The plots were 4 rows wide (10 ft) and 50 ft long with a 10-ft border at the end of each plot. Most miticide treatments were applied with a high clearance sprayer using a 10-ft boom extending over 4 rows. Three hollow cone nozzles were directed at each row (1 nozzle directly over the row and 1 on each side of the row on 18-inch drop hoses). The sprayer was calibrated to deliver 20 gal of water with 30 psi of CO2 pressure. One treatment was applied using three 3/4 inch rain drop nozzles mounted on the high clearance sprayer at tassel height between the rows to simulate a chemigation application. This system was calibrated to deliver 5430 gal of water with 20 psi. The treatments were applied on 12 Aug. Mite counts were made by visually searching the leaves on 1 side of 8 flagged plants in each plot for larger mites (mostly adult females). These plants had previously been infested (1 to 2 wk pretreatment) with mites, 4 plants with TSSM from a newly established greenhouse colony, and 4 plants with Banks grass mites from an infested corn field. Pre-treatment counts were made 1-6 Aug and posttreatment counts were made 21-27 Aug. Mite samples were collected with a vacuum sampler from each of the 2 groups of flagged plants in each plot. Forty mites from each sample were selected at random and mounted for microscopic examination and species determination. The percent TSSM in each sample was then calculated. This test was designed to test these miticides against both the Banks grass mite and the TSSM; however, the plots were found to contain predominantly TSSM when the posttreatment counts were made. Therefore, the counts from all 8 plants in each plot were combined for analysis. Grain yields were determined by hand harvesting 40 row-ft from the 2 center rows in each plot 1-4 Sep. All yields were corrected to 15.5% moisture.</jats:p

Corn Borer Efficacy Test, 1983

Abstract This experiment was conducted on a furrow-irrigated cornfield at the Garden City Exp. St. in Finney County, Kans. Fifteen treatments were arranged in a randomized complete block design with four replications. Each plot was 3 m wide (4 rows) and 15 m long surrounded by a 3 m wide border of untreated corn. Chemical treatments were applied twice, on 4 and 17 Aug. with a high clearance sprayer, using a 3 m boom with three nozzles directed at each row (one nozzle directly over the row and two suspended on 46 cm drop hoses). The first application was made near the middle of the southwestern corn borer flight. The sprayer was calibrated to deliver 20 gal of water/acre with 30 lb/in2 of CO2 pressure. About a week before treating the plots, four plants were selected from the center two rows of each plot and flagged. These plants were innoculated with banks grass mites in an effort to augment the natural population of banks grass mites. Counts were made by visually searching the leaves on one side of each of these marked plants (0.5 plant) for adult female mites. Corn borer counts were made in mid-Sept, by disecting 10 consecutive corn plants per plot. Grain yields were obtained by hand harvesting 18m from both of the center rows.</jats:p

Bioassay of Two Greenbug Strains with Parathion and Chlorpyrifos, 1989

Abstract A laboratory study was conducted to determine if 2 strains of greenbugs differed in their susceptibility to 2 commonly used insecticides, parathion and chlorpyrifos. Greenhouse colonies were established from greenbugs collected from sorghum fields in Gove County and Haskell County, Kansas during the summer of 1989. The greenbugs in the Haskell County field had survived aerial applications of 0.75 lb (AI)/acre of parathion on 19 Aug and 0.5 lb (AI)/acre of parathion plus 0.25 lb (AI)/acre of Cygon on 24 Aug. The greenbugs in the Gove County field had not received any known insecticide treatment in 1989. Stock solutions containing 5 mg (AI)/ml of technical chlorpyrifos or parathion were prepared using histological grade acetone. Serial dilutions of each stock solution were made to obtain solutions with from 500 to 0.005 jig^Aiyml. The interiors of 1-dram glass vials were coated with 0.2 ml of each solution to form a series of vials with 0.001, 0.01, 0.1, 1, 10, or 100 u.g (AI)/vial. Control vials were treated with 0.2 ml of acetone. The trial was conducted on 9 Nov. Ten late instar greenbugs were placed in each vial and each concentration was replicated 5 times (50 greenbugs/concentration or 350 greenbugs from each colony for each chemical). Mortality was recorded after 7 h. Aphids incapable of coordinated movement were counted as dead.</jats:p

Efficacy of Miticides Against Corn Spider Mites, 1986, #2

Abstract This experiment was conducted in Finney County, KS in a field of flood irrigated corn where the natural mite populations were augmented with twospotted spider mites. Thirteen treatments were arranged in a randomized complete block design with 4 replications. The plots were 4 rows wide × 10 ft, 50 ft long, and surrounded by 10 ft borders of untreated corn. Prior to treatment, 4 plants in each plot were selected from the center 2 rows and flagged. The natural mite population was augmented by attaching leaves infested with twospotted spider mites from a greenhouse colony. Treatments were applied with a high clearance sprayer using a 10 ft boom with 3 nozzles directed at each row (1 nozzle directly over the row and 1 on each side of the row on 18 inch drop hoses). The sprayer was calibrated to deliver 20 gpa of water with 30 psi of CO2 pressure. The plots were treated on 9 Aug. Spider mite counts were made from the flagged plants by searching every other leaf on each plant for large mites (primarily the adult females). Pretreatment counts were made on 29 Jul and the posttreatment counts were made on 14 Aug. The percentage of twospotted spider mites present in each plot was determined by collecting 20 to 40 mites from the flagged plants in 2 of the replicates with a small vacuum sampler and mounting them for microscopic determination of mite species.</jats:p