B. R. Leonard

Oviposition and Sex Ratio of the Redbanded Stink Bug, Piezodorous guildinii, in Soybean.

Redbanded stink bug, Piezodorus guildinii (Westwood), is a significant soybean pest across the mid-south region of the United States. The objectives of these studies were to characterize: (1) redbanded stink bug oviposition in relationship to soybean maturity group (MG), plant structure, crop phenology, and vertical distribution within the plant canopy; and (2) redbanded stink bug adult sex ratios in relationship to soybean phenology. A total of 5645 redbanded stink bug eggs in 421 egg masses (clusters) were field collected from naturally-occurring populations in MG IV and V soybean over a three year period (2009 to 2011). The mean number of eggs within a cluster was 16.6 ± 0.3. Plant structures by MG interactions were highly significant with more egg masses oviposited on leaves in MG IV (79.4%) and more on pods in MG V (72.7%). The ratio of females to males was similar in all soybean growth stages except R5, where the sex ratio increased to 1.4:1, coinciding with peak oviposition. Only 29.9% of egg clusters in MG IV and 18.3% of egg clusters in MG V were oviposited in the upper 35 cm of the soybean canopy. Based on these results, sampling strategies and insecticide application placement for stink bugs may require modification.

EVALUATION OF RADIANT (SPINETORAM) EFFICACY AGAINST THRIPS ON SEEDLING COTTON, 2009

Selected foliar insecticides were evaluated for control of thrips on cotton seedlings at the Macon Ridge Research Station (Franklin Parish). Cotton seed were planted into a Gigger-Gilbert silt loam soil on 21 Apr. Plot size was four rows (40-inches on centers) X 50 ft. Treatments were placed in a RCB design with four replications. Insecticides were applied with a hand boom and compressed air system calibrated to deliver 10 gpa through TeeJet 8015 flat fan nozzles (2/row) at 32 psi on 20 May. Insecticide efficacy was measured by randomly selecting 10 plants per plot and counting the number of thrips (immatures and adults) at 2 DAT (22 May), 5 DAT (25 May), 7 DAT (27 May) and 13 DAT (2 Jun). Plant samples were processed using whole plant washing procedures to remove thrips. Thrips were counted using a dissecting microscope. Data were subjected to ANOVA and means separated according to DNMRT. Total rainfall of 1.66 inches occurred during the test.

EVALUATION OF SELECTED INSECTICIDES FOR CONTROL OF SOYBEAN LOOPER AND STINK BUG, 2007

Selected insecticides were evaluated for control of SBL and a stink bug complex (SBC) in two tests at the Macon Ridge Research Station (Franklin Parish). Soybean seed (Asgrow 5501) were planted into a Gigger silt loam soil on 11 Jun in Tests 1 and 2. Plot size was four rows (40-inches on centers) x 50 ft. Treatments were placed in a RCB design with four replications in both tests. Insecticides were applied on 21 Aug in Test 1 and 27 Aug in Test 2 with a John Deere high clearance sprayer and CO2-charged system calibrated to deliver 6 gpa through Teejet TX-6 hollow cone nozzles (2/row) at 48 psi. Treatment efficacy against SBL and SBC was determined at 2, 6, and 9 DAT in Test 1 and 2, 4, and 8 DAT in Test 2 using a standard (15 inches diameter) sweep net and taking a 25 sweep sample in each plot. Data were subjected to ANOVA and means separated according to DMRT. No rainfall occurred during these tests.

EVALUATION OF FOLIAR INSECTICIDE EFFICACY AGAINST THRIPS ON SEEDLING COTTON, 2007

Selected foliar insecticides were evaluated for control of thrips on cotton seedlings at the Macon Ridge Research Station (Franklin Parish). Cotton seed were planted into a Gigger-Gilbert silt loam soil on 7 May. Plot size was four rows (40-inch centers) X 25 ft. Treatments were placed in a RCB design with four replications. Foliar insecticides were applied with a handboom and compressed air system calibrated to deliver 10 GPA through TeeJet 8001 flat fan nozzles (2/row) at 20 psi on 25 May and 4 Jun. Insecticide efficacy was measured by randomly selecting 10 plants per plot and counting the number of immatures and adults on 28 May (3 DAT1), 1 Jun (7 DAT1), and 7 Jun (3 DAT2). Plant samples were processed using whole plant washing procedures to remove thrips. Thrips were counted using a dissecting microscope. Seedling damage was estimated visually using a 0-5 rating scale with 0 as no damage and 5 representing severe damage. Seedling damage was evaluated on 4 Jun (10 DAT1) and 13 Jun (9 DAT2). Data were subjected to ANOVA and means separated according to DMRT. Total rainfall of 4.95 inches occurred during the test.

EVALUATION OF SELECTED INSECTICIDES FOR CONTROL OF RED BANDED STINKBUGS AND THREECORNERED ALFALFA HOPPERS, 2006

Selected insecticides were evaluated for control of RBSB (adults) and TCAH (adults and nymphs) in soybean at the LSU Agricultural Center’s Sweet Potato Research Station (Franklin Parish). Soybean seed were planted into a Gigger silt loam soil on May 19, 2006. Plot size consisted of eight rows centered on 40-inches and 50 ft in length. Treatments were placed in a RCB design with five replications. Insecticides were applied on 11 Aug with a John Deere high clearance sprayer and CO2-charged system calibrated to deliver 6 gpa through Teejet TX-8 hollow cone nozzles (2/row) at 60 psi. Treatment efficacy against RBSB and TCAH was determined at 3, 5, and 7 DAT using a standard (15 inches diameter) sweep net and taking a 25 sweep samples in each plot. Data were subjected to ANOVA and means separated according to DMRT. No rainfall occurred during these tests.

EVALUATION OF SELECTED INSECTICIDES AGAINST STINK BUG (PIEZADORUS GUILDINII (WESTWOOD)) ON COTTON BOLLS, 2005

Selected insecticides were evaluated for their effectiveness against P. guildinii on cotton bolls at the Macon Ridge Research Station (Franklin Parish). DeltaPearl cotton seed was planted on May 2 in a Gigger-Gilbert silt loam soil. Plots consisted of four rows centered on 40-inches and 30 ft in length. Treatments were arranged in a RCB design with four replications. Insecticides were applied with a tractor-mounted boom and compressed air system calibrated to deliver 10 gpa through Flatfan 80015 twin jet nozzles (2/row) at 30 psi on 3 Aug. First position quartersized bolls in the upper one-half of the plant were harvested and placed in 29.5 ml plastic cups. Ten plants were sampled for one boll/plant in each of the four replicates. The samples were placed on ice and transported to the laboratory. One P. guildinii stink bug adult was infested in each cup (1 bug/boll/cup). Insect mortality was rated 24, 48, and 72 h after infestation (HAI). A stink bug was considered dead if it was unable to right itself within 15 s after being inverted with a metal probe. Data were subjected to ANOVA and means separated according to DMRT. No rainfall occurred between insecticide application and boll removal from the field.

EVALUATION OF SELECTED INSECTICIDES AGAINST HELIOTHINES IN COTTON, 2004

Cotton seed were planted 5 Jun in plots consisting of four rows (centered on 40 inches) x 50 ft. Treatments were arranged in a RCB design and replicated four times. Insecticides were applied with a hi-clearance sprayer and CO2 charged system calibrated to deliver 6 gpa through Teejet TX-8 hollow cone nozzles (2/row) at 48 psi. Insecticides were applied on 23, 28 Jul, and 1 Aug. Treatments were evaluated by examining 50 flower buds (squares) per plot on 27, 31 Jul, and 5 Aug, for evidence of bollworm (BW) and tobacco budworm (TBW) damage and squares infested with larvae. Data were analyzed with ANOVA, and means were separated according to Tukey’s test.