Timing Of Insecticide Applications Research Articles

Effects of selected insecticide formulations, phased application and colony management strategies on honey bee mortality in processing sweetcorn

SUMMARYThese studies were undertaken to evaluate different strategies for reducing losses of honey bees (Apis mellifera) due to the use of insecticides in commercial sweetcorn (Zea mays) production fields. The strategies were: (1), insecticide application timed to avoid peak flowering periods in sweetcorn; (2), insecticide formulation, including carbofuran, encapsulated methyl parathion, permethrin and a tank mix of car- baryl plus parathion; (3), the use of pollen traps to prevent contaminated pollen coming into the hive; and (4), feeding (engorgement) of colonies with sugar syrup immediately following insecticide application to reduce honey bee foraging. Timing of insecticide applications was ineffective and a practical impossibility. Bee mortality was less with permethrin than with the other materials tested. Pollen traps and colony feeding may reduce bee mortality under some circumstances; however, these strategies proved unreliable and further study is needed. The data show that bees foraging on ragweed (Ambrosio spp.) adjacent to sweetcorn fields, rather than on sweetcorn, may be responsible for generating the excessive bee losses associated with sweetcorn. The results further indicate that circumstances in each field are unique due to prevailing conditions at each site, e.g. clean cultivation, competing resources, insecticide tank mixes, and other nearby applications. Finally, we find it highly significant that we were unable to induce high levels of bee mortality by applying our test compounds at the rate given by the manufacturers.

Application Timing of Insecticides for Control of Annual White Grubs on a Golf Course Rough, 1996

Abstract This study was conducted in Lincoln, NE on a golf course rough. The turf (50% Kentucky bluegrass and 50% perennial rye) was maintained at a mowing height of 2.0 inches. Thatch accumulation (finger compressed) in the plot area was 0.75 inches. Field conditions at the study site were: soil type, silty cla> loam; soil organic matter, 3.5%; soil pH, 6.5; water pH, 7.0. Environmental conditions at the time of application on 18 Jun, 09 Jul, and 06 Aug were, respectively, as follows: soil moisture 20%, 19%, and 20% by wt; air temperature 81°F, 74°F, and 87°F; soil temperature 72°F, 74°F, and 77°F; relative humidity 63%, 39%, and 66%; wind direction and velocity 155° at 3 mph., 22° at 6 mph, 204° at 12 mph. Plots were 6 X 10 ft and the experimental design was a RCB with 3 replications. Liquid insecticides were applied using a CO2 sprayer with a TeeJet® 8002 nozzle at 30 psi and delivering 2 gal/1000 ft2 Following applications, plots were irrigated with 0.35 inch water. Post-treatment precipitation totaled 13.71 inches. Treatments were evaluated 77 days after the first application on 3 Sep by removing from each plot three, 8-inch diam turf-soil cores (1.05 ft2 total area) to a depth of 3 inches and counting the number of surviving grubs

Timing of Insecticide Applications to Control White Grubs, 1996

Abstract Two insecticides were applied on three dates coinciding with different stages of Japanese beetle development at the Orchard of Golf Driving Range in West Lafayette, IN. Treatment plots were 10 x 10 ft, arranged in a RCB design, replicated 4 times, with 3 untreated plots in each replicate. Treatments were applied on 27 Jun (pre-egg laying), 2 Aug (egg laying to first instar), and 23 Aug (first to second instar). Merit 0.5G was applied with a homemade salt shaker. RH-0345I01 was applied at 34.5 gpa and 40 psi using a CO2-powered backpack sprayer with 8002 nozzle tips. Irrigation (0.5 in) was applied to plot areas within 30 h after applying treatments. Evaluation was done on 28 Sep by extracting cores from five random locations within each plot using a golf-hole cup cutter (0.90 sq ft.). Soil to a depth of 4 inch, thatch and turfgrass from each core was examined for the presence of live grubs. The average number of live grubs in five subsamples within each plot was used as the dependent variable in the statistical analysis of the data.

Evaluation of Insecticides for Control of Heliothine Larvae on Cotton (Trial 1), 1996

Abstract This test was designed to evaluate the effectiveness of larvicides and larvicide combinations for the control of TBW and BW in cotton in Mississippi. Plots were 4 rows wide and 50 ft long with four untreated rows or a 10 ft planted buffer between plots. Plots were sampled at 3-4 day-intervals throughout the growing season for square damage, larvae in terminals and squares, and eggs in terminals. Twenty-five randomly selected terminals and squares in each plot were sampled, and treatment was initiated when population levels reached treatment threshold according to recommendations in the Mississippi Cotton Insect Control Guide. Other pests occurring throughout the season were treated according to the Mississippi Cotton Insect Control Guide recommendations. All insecticide applications were applied with a high clearance spray tractor equipped with two TX 4 hollow cone nozzles per row traveling 4 mph and delivering 5 gpa. Plots within a replicate were sprayed sequentially to maintain true replicate integrity. Applications were made on 24 Jun, 4, 10, 22 and 29 Jul, and 7 Aug. Yield was estimated by mechanically harvesting the center 2 rows of each plot. Rain was frequent during the trial and caused poor timing of insecticide application, contributing to reduced residual efficacy of insecticides.

Scirpophaga incertulas (Walker) (Lepidoptera: Pyralidae) and deepwater rice — an integrated view

The role played by the lepidopteran yellow stem borer, Scirpophaga incertulas (Walker) in the life cycle of deepwater rice ( Oryza sativa) is controversial. The major question is whether or not larval feeding in the elongated stems is damaging and if so, although no visible symptoms can be observed, leads to loss of yield. Drawing on evidence from entomological and agronomic studies, especially in Bangladesh and Thailand, this paper shows that there is little or no correlation between early- or mid-season borer infestation and yield; that stem density always declines from a pre-flood maximum, irrespective of borer infestation; how late-season infestations can lead to serious crop loss; and, how a promising concept for strategic timing of insecticide application was developed and tested.

Attractants for Adult Southern Corn Root worm (Coleoptera: Chrysomelidae) Monitoring in Peanut Fields and Relationship of Trap Catch to Pod Damage

Field studies were conducted in 12 locations in southeastern Virginia to evaluate 3 trap attractants, 1,2,4-trimethoxybenzene, indole and trans-cinnamaldehyde (TIC), trans-cinnamaldehyde, alone, and sex pheromone (10-methyl-2-tridecanone), for monitoring adult southern corn root worm, Diabrotica undecimpunctata howardi Barber, phenology in peanut, Arachis hypogaea L.; and to determine the relationship of trap catch to peanut pod damage as it occurred throughout the season. Pheromone traps caught more beetles than TIC or cinnamaldehyde on most sample dates and at most locations. Pheromone traps detected 2 distinct beetle peaks, the 1st between 16 and 23 June, and the 2nd between 21 and 28 July, and consistently caught more males than females. TIC and cinnamaldehyde traps caught more females in 14 out of 180 observations (15 sample dates, 12 locations) and failed to detect the 2nd beetle peak. Peanut pod damage began to increase in all locations at the end of July. Total pod damage (immature plus mature pods) exceeded 40% in all but one location. Peak damage occurred at all but 1 location on ≈11 August. Peak pod damage by southern com root worm larvae consistently lagged behind the 2nd peak in the beetle population by 2.1 ±0.5 (±SEM) wk. Number of beetles trapped accounted for only 10% of the variance observed in peak pod damage. Use of pheromone traps by growers could allow for a more precise timing of insecticide applications and improve management of southern corn root worm in peanut.

Evaluation of Insecticides Against Lepidopterous Pests in Cranberries, 1995

Abstract This trial was conducted on a bed of ‘Earlyblacks’ at the Rutgers Blueberry and Cranberry Research Center, Chatsworth, NJ. Treatment plots were arranged in a RCB design with 5 replications. Plots were 4-m by 4-m, separated by buffers of 1-m strips of cranberries within each block and 3-m between blocks. GM larval populations in each plot were augmented on 7 May by placing 4 eggmasses, obtained from USDA-APHJS facility at Otis Air Base in Cape Cod, MA. All GM eggmasses completed hatching by 10 May and larvae were well distributed in each plot at the time of insecticide application. Treatments were applied once on 20 May with a CO2 pressurized Model T backpack sprayer (R & D sprayers) equipped with a single TeeJet nozzle (8002VS). The sprayer was operated at 35 PSI and calibrated to deliver 250 GPA finished spray. Most larvae of SFW and BHFW were third and fourth instar at the time of insecticide application. Larval population was assessed by examining all uprights in 4 randomly selected 1 -ft2 areas per replicate. Pre-treatment estimates were made 15-16 May and post-treatment counts on 31 May. GM larval counts were not taken before the application of insecticides. Larval counts of BHFW and SFW were pooled because of low pest pressure.

Evaluation of Insecticide Application Timing on Sorghum Midge Injury to Grain Sorghum, 1995

Abstract The test was conducted at the Macon Ridge Location of the Northeast Research Station in Franklin Parish, LA. Plots (28 ft X 8 rows) were planted on a Gigger-Gilbert silt loam on 15 Jun in a RCB design with 5 replications. Karate 1EC at 0.02 lb (AI)/acre was applied with a high clearance sprayer equipped with a CO2 charged system calibrated to deliver 9.3 gpa at 46 psi and 3.3 mph through TX-8 hollow-cone nozzles (2/row). Application timing for each treatment was determined by selecting and tagging 20 plants from the 2 center rows before spraying. For the 50% and 90% panicle emergence treatments, 10 and 18 plants, respectively, had panicles completely emerged with no open flowers. For the 20, 50 and 90% flowering treatments, 4, 10 and 18 of 20 tagged plants per plot, respectively, had flowering panicles. A panicle was considered to be flowering when the upper 25% portion had open spikelets. Treatments were applied on 28 Jul for the 50 and 90% panicle emergence and on 31 Jul for the 20, 50 and 90% panicle flowering. Sorghum midge damage to seed heads was evaluated on 24 Aug by estimating percent blasted kernels on each tagged plant. Sorghum seed yields were obtained on 8 Sep by manually harvesting panicles from the 20 tagged plants and by mechanically harvesting the entire 2 center rows in each plot.

Insecticide Toxicity in European Corn Borer (Lepidoptera: Pyralidae): Ovicidal Activity and Residual Mortality to Neonates

Field and laboratory studies were conducted using selected carbamate, organophosphate, and pyrethroid insecticides to quantify their toxicity to European corn borer, Ostrinia nubilalis (Hubner), eggs and residual mortality to neonates. Field studies included most insecticides currently registered for O. nubilalis on vegetable crops, as well as recently developed pyrethroids. Insecticides with the greatest ovicidal activity in field trials, in decreasing order, included methomyl, encapsulated methyl parathion, permethrin, thiodicarb, zeta-cypermethrin, and lambda-cyhalothrin. With the exception of methomyl, significant larval mortality was also observed for each material. Of all materials tested, only methomyl previously was assumed to have ovicidal activity on O. nubilalis. Laboratory bioassays were conducted to estimate the LC 50 for insecticides showing the greatest ovicidal activity in the field. Insecticides with the greatest ovicidal included, in decrasing order, zeta-cypermethrin, lambda-cyhalothrin, permethrin, methyl parathion, esfenvalerate, and methomyl. With the exception of methomyl, all insecticides demonstrated high levels of residual toxicity to neonates. Ovicidal activity of methomyl in the field but low inherent toxicity to eggs in the laboratory bioassay was partially explained by the use of a higher field rate relative to the pyrethroids. Results from this study will be useful for improving the timing of insecticide applications against O. nubilalis and necessary for refinement of an O. nubilalis management model

REPO: A Simulation Model That Explores Colorado Potato Beetle (Coleoptera: Chrysomelidae) Adaptation to Insecticides

A simulation model (REPO) was developed to predict the rate of resistance development in Colorado potato beetle, Leptinotarsa decemlineata (Say), given various genetic, biological, and management conditions. Values used in exploring variables in the model were chosen to reflect the range of possibilities encountered in field populations of Colorado potato beetle. REPO is different from other resistance management models in that it is temperature-driven, considers age-specific selection, describes the pattern of immigration of colonists, and uses survivorship functions to describe dynamic relationships among genotypes during insecticide selection. The life history of Colorado potato beetle in North Carolina and other areas is presented as a backdrop to model exploration of some of the unique features of this pest that could influence resistance evolution. Foremost among ecological and management factors influencing rate of resistance development were the arrival period of colonizing beetles, timing of insecticide applications, action thresholds, and age-specific selection. Relevance of these findings to management of Colorado potato beetle and future research on this insect is discussed.

Sex pheromone traps for detecting and monitoring the raisin moth,cadra figulilella, in date palm plantations

Field tests were carried out to determine whether pheromone traps, baited with (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:Ac) impregnated in rubber septa (Maavit, Israel), could provide a reliable tool for monitoring the raisin moth,Cadra figulilella (Gregson), in date palm plantations. No significant differences were detected between captures of males in traps baited with 1 or 10 mg pheromone/dispenser. However, traps baited with 1 mg pheromone captured significantly more males than those baited with 0.1 mg pheromone/dispenser. No differences were found between captures of males in traps hung at a height of 8 m (near the bunches) or 2–3 m (on palm trunks). Two peaks of male capture were detected, one in May-June and the other during September-October (ripening period). Results indicate a positive relationship between captures in traps and infestation levels by larvae. Pheromone traps baited with 1 mg Z9,E12–14:Ac impregnated in rubber septa and hung on palm trunks (at a height of 2–3 m), were very useful for monitoringC. figulilella populations and for determining the accurate timing of insecticide applications.

Timing of Insecticide Applications Against Second-Generation European Corn Borer, 1991

Abstract Efficacy of Penncap M 2 FM at 5 different timings was evaluated against second-generation ECB in a commercial production field at the Southwest Experiment Station in Lamberton, MN. The field, planted on 3 Jun to an 85 day RM variety, was tasseling and silking as the second generation moth flight peaked; it attracted significant egg laying (>2.5 egg masses per plant). Treatments were applied at 3-4 day intervals beginning 6 Aug to plots measuring 4 rows (76 cm centers) X 30 m. Treatments were arranged in a randomized complete block design with 5 replications. Applications were made with a Hagie Hi-Boy sprayer at 6.4 km/h delivering 174 liters/ha through 8002E drop nozzles. Application dates of 6, 9, 13, 16, and 20 Aug corresponded to ECB infestation predominantly in these stages: egg (15% hatch), egg and first instar (55% hatch), first instar (80% hatch), 2nd instar, and 3rd instar, respectively. Efficacy was evaluated on 18 Sep by dissecting 20 plants and counting tunnels in ear shank and stalk. Preharvest measurements of broken stalks, ear droppage, and % kernels damaged were made on 25 Sep. Plots were harvested by combine on 11 Oct and yields adjusted to 15.5% moisture.

Control of White Grubs in Bermudagrass Sod, North Carolina, 1990

Abstract Plots were established on a golf course rough at the Oak Island Golf Course near Caswell Beach. The bermudagrass rough contained a variety of weed species and was maintained at a height of 8 cm with 1 cm of thatch. Soil was a sand with a pH of 5.8 and 1.2% humic matter. Treatments were applied 27 Mar to 3.0 × 3.0 m plots arranged in a randomized complete block with 4 replications. Air temperature was 75°F and soil temperature was 63°F. Soil was moist at time of insecticide application. Granular formulations were applied in a hand held glass jar shaker with a perforated top. Sprays were applied with a CO2-pressurized backpack sprayer delivering 135 ml/plot (332 liters/ha) at 40 psi. After application all plots were irrigated with 0.7 cm of water. Pretreatment inspections revealed grubs to be Southern masked chafers. Plots were sampled on 10 Apr (14 DAT) using a 20 cm diam core sampler to a depth of 20 cm (most grubs were within 3 cm of the soil surface during both treatment and sampling). Five sample sites/plot were selected at random. All grubs were counted and removed from the soil core. Sampling on 24 Apr (28 DAT) found that a significant portion of the grubs had pupated due to an extremely mild winter and advanced development and thus was considered invalid. Counts from the 5 samples were summed for each plot and the data were transformed X + 0.5 prior to analysis.

Degree-Day Model for Development of Calocoris norvegicus (Hemiptera: Miridae) and Timing of Management Strategies

A degree-day model for Calocoris norvegicus (Gmelin) has been developed that uses the first-observed, first-instar nymph as a biofix and predicts the time of development to each stage. This model is useful for timing control tactics in pistachios before Calocoris disperses from surrounding host plants. Based on laboratory studies at five different temperatures, the lower developmental threshold was estimated at 6.39°C. Development from newly emerged nymph to the fourth instar required a mean of 142 degree-days (DO). Seasonal phenology data from a pistachio orchard in the Sacramento Valley in 1987 and 1988 indicated that the degree-day interval to peak levels of fourth-instar nymphs was 122 and 159 DD after the first instar. Before field implementation, final validation of the degree-day model will require extensive phenology data in multiple locations. Timing of insecticide applications before the dispersal of Calocoris in the ground cover bordering the pistachio orchard significantly reduced the level of epicarp lesion damage.

Sod Webworm Prevention in Corn, 1987

Abstract Yellow field corn was slot-planted in atrazine/2,4-D treated sod using 38-inch rows and a seed drop of 22,000 seeds/acre. The sod was dead at the time of insecticide application. Fields in the vicinity of the study area, 1 mile south of Delphos, Ringgold Co. IA, had a history of sod webworm infestations. Plots were planted on 3 May. Test 1 utilized a randomized complete block design with 4 replications. Plots measured 12 rows by 75 ft. Broadcast applications were made on 5 May using a 10-ft boom sprayer mounted on a Honda ACT 110 and equipped with Tee-Jet 8004 LP nozzles spaced 20 inches apart. Spray was delivered at 21 psi and 20 gal/acre using CO2 as a propellant. Banded applications differed only in that Tee-Jet 8003 E nozzles were spaced 38 inches apart to deliver a 12-inch band centered over each row. Stand and damage counts were taken from 18.0 row ft in the center of each of the 2 middle rows in each plot. Damage determinations were made as in Test 2. All data were normalized before analysis with a SQRT (x = 1.0) transformation. Test 2 used Magnum slurried onto Pioneer 3377 at 8 oz/bu. Magnum treated seed was placed in 4 adjacent boxes of an 8-row planter. Ten rounds were planted, resulting in 20 alternating treated and untreated strips each 8 rows wide. Data were collected by measuring 300 ft into the field then examining plants in the next 18 row ft of the 2 center rows in each strip. Stand counts taken on 11 May showed no significant differences. Efficacy data taken on 21 May were determined by counting the number of sod webworm damaged plants per sampling area.

Control of Velvetbean Caterpillar on Soybean, 1989

Abstract Plots measuring 45 ft by 8 rows (36 inch row spacing) were arranged in a randomized complete block design with 4 replications. Insecticides were applied with a CO2 pressurized backpack sprayer calibrated to deliver 15 gal/acre at 21 psi through 8002 nozzles. Treatments were applied on 18 Sep in the R5 growth stage. Samples were taken 2 and 7 DAT using 2, 25-sweep samples (15 inch diam sweep net)/plot, and 14 DAT using one 25-sweep sample/plot. ‘Bond’ sticker was applied with each insecticide at the rate of 5 ml/gal of finished spray. Populations of VBC reached approximately 57% of the economic threshold (75 VBC/25 sweeps) at the time of insecticide application.

Effect of Insecticide Applications in Soybeans on Trissolcus basalis (Hymenoptera: Scelionidae)

Field studies were conducted to determine the effect of the primary insecticides that are applied to control Louisiana soybean insect pests on the survival of an important biological control agent of stink bugs (Hemiptera: Pentatomidae). Adult egg parasitoids, Trissolcus basalis (Wollaston), were affected little by permethrin field applications, but methyl parathion had an adverse but short-lived effect on parasitoid survival. High levels of adult parasitoid mortality were observed only within the first 6 h following methyl parathion application. Neither insecticide affected emergence of parasitoids from their host eggs, suggesting that stink bug eggs provided a barrier to insecticide penetration. However, parasitoids apparently contacted insecticide residues when chewing through host egg shells to emerge, resulting in some mortality after emergence, caused by methyl parathion. The degree of this mortality was affected by three factors: parasitoid developmental stage at time of insecticide application, position of parasitized egg masses in the soybean canopy, and parasitoid gender. Overall, results of this study suggest a general compatibility between a major biological control agent of stink bugs, T. basalis , and insecticidal control of stink bugs and lepidopterous pests in Louisiana soybeans.

Sampling Pink Bollworm (Lepidoptera: Gelechiidae) Eggs: Potential for Improved Timing and Reduced Use of Insecticides1

A presence-absence egg sampling plan for pink bollworm (PBW), Pectinophora gossypiella (Saunders), developed to provide a more accurate index of moth (target stage) activity, was evaluated during 1986 to determine whether egg sampling rather than conventional larval sampling provided more optimal timing of insecticide applications. The large-scale field test (260 ha) consisted of 16 commercial fields, ca. 16.2 ha each, in the Palo Verde Valley, Calif. Of the eight fields that were treated based on egg sampling (treatment threshold, 6 to 8% egg-infested bolls), an average 35% seasonal reduction in insecticide use was obtained when compared with larval sampling. Despite the reduction in insecticide use, PBW larval infestations were not significantly different in fields sampled for eggs and fields sampled for larvae from June to September. Lint yields as well as lint quality parameters were also not significantly different between the two sets of fields. Economic and environmental benefits of a 35% reduction in insecticide use is discussed.

Control of Japanese Beetle Grubs on a Golf Course Fairway, 1987

Abstract Six insecticides were evaluated on a golf course fairway at the Grove Park Inn near Asheville, N.C. The fairway consisted of Kentucky bluegrass and annual bluegrass maintained at a height of 2 inches with 0.5 inch of thatch. Soil type was mineral (0.7% organic matter) at pH 6.6. Treatments were applied 28 Apr (except the second application in the 2- + 2-lb Diazinon split treatment, which was applied 5 May) to 10- × 10-ft plots arranged in a randomized complete block design with 4 replications. Air temperature was 67°F and soil temperature was 58°F. Soil was moist at time of insecticide application. Granular formulations were applied using a hand-held glass shaker jar with a perforated top. Sprays were applied with a COz-pressurized backpack sprayer delivering 30 gal/acre at 40 psi using 8002 flat-fan nozzles. After application, all plots were irrigated with 0.5 inch of water. Plots were sampled on 21 May (23 DAT) by inspecting 1 sq ft of sod and all the underlying soil to a depth of 4 inches (most grubs were within 2 inches of the soil surface during both treatment and sampling). Two samples/plot were selected at random. All grubs (100% Japanese beetle grubs, 3rd instar) were counted and removed. Counts from the 2 samples were averaged and the data were transformed × + 0.5 prior to analysis.

Frequency and Timing of Insecticide Application to Control Rice Tungro Virus (Rtv)

Frequency and Timing of Insecticide Application to Control Rice Tungro Virus (Rtv)