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Tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is the most important insect pest of cotton, Gossypium hirsutum L., in the states of Arkansas, Louisiana, Mississippi, Tennessee, and Missouri. Foliar insecticide sprays are an important tactic within an integrated pest management (IPM) program for this pest which occurs from early flower bud development to cut out, a stage where the plant has reached the capacity for supporting fruiting positions and equivalent to when there are five nodes above the uppermost first position white flower (NAWF 5). Currently, NAWF and heat unit accumulation monitoring is limited, resulting in a need for a more simplified insecticide termination method that has the potential for wider adoption. Experiments were conducted in 2015 and 2016 in the previously mentioned states to determine when to terminate insecticide sprays for tarnished plant bug based on week of flowering. Treatments included terminating sprays after the second through sixth weeks of flowering, a season-long control, and an untreated control. In general, insecticides reduced densities of tarnished plant bugs in the sprayed treatments. When analyzed by location, treatments that resulted in cotton yields similar to the season-long control ranged from weeks two through five of flowering. These data suggest that treatments can be terminated after the fifth week of flowering. Data from this study indicate applications terminated after the fifth week of flowering would be similar to the current recommended termination timing of NAWF 5 plus 350 heat units. Results from this experiment will be used to better define a simplified IPM strategy for tarnished plant bug in cotton.

A complex of thrips species infests seedling stage cotton, Gossypium hirsutum (L.), in the southern United States. Preventive control tactics are recommended to manage early season infestations, but foliar insecticides may be necessary to prevent injury for the duration of seedling development. The objective of this work was to compare efficacy of spinetoram to that of spinosad and current standard products, and to define the minimum effective spinetoram rate for satisfactory control of thrips. Foliar applied insecticides were applied with and without a surfactant against varying thrips infestation levels in field plots. Results demonstrated that infestations comprised primarily of tobacco thrip, Frankliniella fusca (Hinds), were more sensitive to spinetoram than spinosad at equivalent rates of active ingredient. Spinetoram applied at 13.0 to 26.0 g a.i./ha provided control comparable to commercial standards under moderate infestation levels. Consistency and numerical increases in efficacy were observed when applying spinetoram (13.0 g a.i./ha) with a surfactant. Efficacy of spinetoram at 13.0 g a.i./ha in combination with a surfactant was confirmed against onion thrips, Thrips tabaci (Lindeman), and in commercial scale plots. Spinetoram alone was not adequate for managing extremely high (>269 fold greater than a threshold of one thrip per plant) populations of tobacco thrips. These experiments demonstrate that spinetoram, applied at 13.0 to 26.0 g a.i./ha, has utility in the management of thrips infesting cotton seedlings.

A small plot field study was conducted on the Plant Science Research Farm of the Mississippi Agriculture and Forestry Experiment Station, Mississippi State, MS and the Delta Branch Experiment Station, Stoneville, MS. The experiment was conducted in a randomized complete block with 4 replications. Plots were 4 rows (38-inch rows) by 50 ft with 2 buffer rows between plots at the Plant Sci. Res. Farm and 4 buffer rows at the Delta Branch Experiment Station. Treatments were applied at the Plant Sci. Res. Farm on 25 Jul, 1, 14 and 19 Aug. All plots were oversprayed for boll weevil control with Guthion 2L (0.25 lb (AI)/acre) on 30 Aug 12, 20, 28 Sep, and 3 Oct. Plots were evaluated on 30 Jul and 16 Aug by making 5-ft whole plant counts in each plot. Yield data were collected by mechanically harvesting the center 2 rows of each plot on 21 Nov.

A full season study was conducted at the Plant Science Research Farm of the Mississippi Agriculture and Forestry Experiment Station, Mississippi State, MS. Plots were planted to ‘Stoneville 825’ on 7 Jun. All treatments were replicated 4 times and arranged in a randomized complete block design. Each plot was 4 rows (38-inch rows) by 50 ft with 2 buffer rows between plots. Insecticides were applied with a boom-type sprayer calibrated to deliver 6.1 gal/acre total volume at 30 psi through 2 TX-4 nozzles per row. Treatments were applied 26 Jul, 2 Aug, 14 Aug and 19 Aug. All plots were sprayed for boll weevil suppression on 31 Aug, 12 and 20 Sep and 28 Sep and 3 Oct with Guthion 2L (0.25 lb (AI)/acre). Insect populations and plant damage were monitored on 27 Jul, 16 and 21 Aug by making 5-ft whole plant counts in each plot. Yield data were taken on 21 Nov by mechanically harvesting the center 2 rows of each plot.

A small plot field study was conducted on the Plant Science Research Farm at Mississippi State, MS. Plots (4 rows × 45 ft) were planted to ‘Stoneville 825’ cotton on 22 May. The experiment was conducted as a randomized complete block with 10 replicates. Seed treatments were applied to seed by spraying evenly distributed samples on a belt sprayer. Granular applications were made with Gandy applicators, and in-furrow applications of Standak were made with a compressed air sprayer mounted behind the planter wheel. All foliar applications were made with a compressed air sprayer mounted on a Ford 5000 tractor. The sprayer was calibrated to deliver ca. 6.5 gpa total volume with 2 TX-4 nozzles per row. Foliar applications followed 2 different treatment regimes. Some of the treatments were initiated at the first true leaf (ITL) stage of plant growth with a total of 5 early season applications being made on weekly intervals. The alternative treatment regime was initiating early season applications at the pinhead square (PHS) stage of growth and making 4 early season applications on weekly intervals. After the first bloom stage of plant growth, the entire study area was oversprayed on weekly intervals to protect the influence of early season treatment effects. ITL treatments were made on 12, 20, and 27 Jun, and 4, 12, and 16 Jul. PHS treatments were made on 27 Jun, and 4, 12, and 16 Jul. All plots were oversprayed on 12 Jun with dimethoate (0.2 lb Al/acre) to prevent thrips from destroying the test. Subsequent oversprays were made on 20 and 24 Jul, 24, and 3, 13, 20, 22, and 28 Aug, 12, 20 and 28 Sep, and 3 Oct with fenvalerate (0.1 lb Al/acre) and azinphosmethyl (0.25 lb Al/acre) to protect the plots from Heliothis spp. and Anthonomus grandis.

Small plot field studies were conducted at Stoneville, MS and Greenwood, MS to measure the efficacy of various insecticides in control of spider mites on cotton. The experiments were conducted in a randomized complete block with 4 replications. Plots were 2 rows (38 inch rows) by 50 ft with 1 buffer row between plots at Stoneville. Insecticides were applied with a boom-type sprayer calibrated to deliver 4.5 gal/acre at 30 psi through 2 TX-4 nozzles. Applications were made on 6 Jun, 6 and 16 Jul. Plots were evaluated on 2, 11 and 19 Jul by examining 25 upper leaves in each plot for number of spider mites.

A full season study was conducted at the Plant Science Research Farm of the Mississippi Agriculture and Forestry Experiment Station, Mississippi State, MS and the Delta Branch Experiment Station, Stoneville, MS. The experiment was conducted in a randomized complete block with 4 replications. Plots were 4 rows (38-inch rows) by 50 ft with 2 buffer rows between plots at the Plant Sci. Res. Farm and 4 buffer rows at the Delta Branch Experiment Station. Insecticides were applied at the Plant Sci. Res. Farm with a boom-type sprayer calibrated to deliver 6.1 gal/acre total volume at 30 psi through two TX-4 nozzles per row. Treatments were applied on 26 Jul, 2, 14 and 20 Aug. All plots were oversprayed for boll weevil control with Guthion 2L (0.25 lb (AI)/acre) on 31 Aug, 12, 20, 28 Sep and 3 Oct. Plots were evaluated on 1, 16 and 24 Aug by making 5-ft whole plant counts in each plot. Yield data were collected by mechanically harvesting the center 2 rows of each plot on 21 Nov. Plots were sprayed at the Delta Branch on 19 Jul and 17 Aug. Heliothis spp. pressure was low throughout the season. However, plant bugs and spider mites were heavy throughout the season.Whole plant counts were made 24 Jul in each plot. Insect populations and plant damage were monitored on 20 Aug by examining 25 terminals and 25 squares per plot. Yield data were collected by mechanically harvesting one of the center rows on 5 Oct.

A small plot field experiment was conducted on the Delta French Branch Experiment Station, Stoneville, MS. Plots (4 rows × 50 ft with 2 row buffers) were planted to ‘DES 422’ cotton on 7 May. The experiment was conducted as a RCB with 9 replicates per block. All insecticide applications were made with a John Deere high clearance sprayer equipped with a compressed air spray system. The sprayer delivered a spray volume of ca. 4.5 gps through 2 TX-4 nozzles/row. Two basic insecticide treatment regimes were used: (1) initiating applications at the first true leaf (ITL) stage of plant growth, and (2) initiating applications at the pinhead square (PHS) stage of plant growth. In both cases, applications were made on weekly intervals until the first bloom stage of growth. After first bloom all plots except the untreated check were oversprayed with Pydrin, Comite, and Lorsban to prevent subsequent insect damage. ITL treatments were applied on 25 and 31 May, and 5, 13, 19, and 28 Jun. PHS treatments were applied on 5, 13, 19, and 28 Jun. Plots were oversprayed on 6, 16, 23, and 25 Jul, and 3 and 20 Aug. Thrips populations were monitored by shaking the plants in a hill of cotton over a standard cigar box or white pan and counting the number of immature and mature thrips. Ten hills were sampled in each plot.

A full season study was conducted at the Plant Science Research Farm of the Mississippi Agriculture and Forestry Experiment Station, Mississippi State, MS. Plots were planted to ‘Stoneville 825’ on 7 Jun. All treatments were replicated 4 times and arranged in a randomized complete block design. Each plot was 4 rows (38-inch rows) by 50 ft with 2 buffer rows between plots. Insecticides were applied with a boom-type sprayer calibrated to deliver 6.1 gal/acre total volume at 30 psi through 2 TX-4 nozzles per row. Applications were made 26 Jul, 2, and 14 Aug. All plots were sprayed for boll weevil suppression on 22 and 31 Aug, 12, 20, and 28 Sep, and 3 Oct with Guthion 2L (0.25 lb (AI)/acre). Insect populations and plant damage were monitored on 4 and 16 Aug by making 5-ft whole plant counts in each plot. Yield data were taken on 21 Nov by mechanically harvesting the center 2 rows of each plot.