Budworm Control Research Articles

Nontarget impacts of insecticide-based population control of eastern spruce budworm (Lepidoptera: Tortricidae) on nontarget caterpillar communities and parasitism

Abstract Narrow-spectrum insecticides are currently used to control populations of spruce budworm, Choristoneura fumiferana Clemens (Lepidoptera: Tortricidae), in eastern Canada. However, these could have nontarget impacts on other caterpillars – some of which may serve as alternative or alternate hosts to key parasitoids – that are also susceptible to control tactics. This study was conducted to determine how the insecticides, Bacillus thuringiensis variety kurstaki (Btk) and tebufenozide, used to control spruce budworm populations, impact caterpillar communities and associated parasitism rates. Post-treatment field sampling of caterpillars was conducted in 2018 and 2019 in New Brunswick, Canada, at sites treated with either Btk or tebufenozide and at control sites. Caterpillar species richness and abundance, community structure, and parasitism rates were assessed using molecular analyses for 659 collected caterpillars. We found that insecticide applications had no significant impact on abundance, species richness, or parasitism rate relative to the measurements made in the control sites. Nonetheless, a significantly higher caterpillar abundance and lower parasitism rate occurred in Btk-treated sites than in tebufenozide-treated sites. Overall, however, Btk and tebufenozide treatments did not negatively affect the non-budworm caterpillar community under the present conditions of low caterpillar densities, suggesting that parasitoids have alternative and alternate hosts after treatments that target the spruce budworm.

一类具有时滞的云杉蚜虫种群模型的Hopf分岔分析

The dynamic behavior of a population model with stage structure for spruce budworms with time delay was investigated. Firstly, existence of a unique positive equilibrium of the model was discussed and sufficient conditions for local stability of the positive equilibrium and Hopf bifurcation occurrence were obtained. Next, the direction of the Hopf bifurcation and the stability of the periodic bifurcation solutions were analyzed with the normal form method combined with the center manifold theorem. Finally, some numerical simulations to verify the theoretical results were also conducted. The work provides an applicable reference for control of spruce budworms.

파프리카 재배기간 중 담배나방 방제에 사용되는 살충제의 잔류특성

BACKGROUND: This study was carried out to investigate the residual characteristics of insecticides used for Oriental Tobacco Budworm control and to establish the recommended pre-harvest residue limit leading to contribution in safety of paprika production. METHODS AND RESULTS: The recommended Pre-Harvest Residue Limits (PHRLs) of insecticides during cultivation of paprika were calculated from residue analyses of insecticides in fruits 1, 3, 5, 7, 10, 12, 15, 18 and 21 days after treatment. Paprika samples were extracted with QuEChERS method and cleaned-up with amino propyl SPE cartridge and PSA, and insecticide residues were analyzed either by HPLC/DAD or GLC/ECD. The limits of detection were 0.01 mg/kg for 5 insecticides. Average recoveries were - of 5 insecticides at fortification levels of 0.1 and 0.5 mg/kg. The biological half-lives of the insecticides were 8.5 days for bifenthrin, 11.8 days for chlorantraniliprole, 16.8 days for chlorfenapyr, 7.1 days for lamda-cyhalothrin and 31.3 days for methoxyfenozide at recommended dosage, respectively. CONCLUSION(S): The pre-harvest residue limits for 10 days before harvest were recommended 1.05 mg/kg, 1.41 mg/kg, 0.93 mg/kg, 2.06 mg/kg and 1.08 mg/kg as bifenthrin, chlorantraniliprole, chlorfenapyr, lamda-cyhalothrin and methoxyfenozide, respectively. This study can provide good practical measures to produce safe paprika fruit by prevention of products from exceeding of MRLs at pre-harvest stage.

C. P. Alexander review

AbstractThe Canadian registration in 2007 of Disrupt SBW Micro-Flakes®, a pheromone-based product for control of spruce budworm,Choristoneura fumiferana(Clemens), paved the way for large-scale trials to test the practicality of mating disruption as a commercial pest management strategy. We review results from field and laboratory experiments on pheromone-based mating disruption of spruce budworm conducted from 1974 to 2008. Application of pheromone from the ground or the air consistently reduced the orientation of males toward pheromone sources. Mating disruption also reduced the mating success of caged or tethered females in 15 of 16 field studies where this parameter was recorded, but had only a limited effect on the mating success of feral females. No consistent difference in the density of egg masses in control and treated plots was observed, which has often been attributed to immigration of gravid females into pheromone-treated plots. Laboratory studies suggest that false-trail following is the predominant mechanism underlying mating disruption in spruce budworm. The enhanced mating success of females with increasing population density suggests that mating disruption should target low-density emergent populations during the initial phase of an outbreak. Constraints that may limit the potential of mating disruption as a management tool include (1) difficulties associated with obtaining accurate sampling estimates at low population density to forecast the onset of outbreaks, (2) potential behavioral adaptations by which females enhance their mating success when the atmosphere is treated with pheromone, and (3) long-range dispersal of females by flight.

Screening of two Trichogramma species, native to southeastern Brazil, for the control of tobacco budworm

The biological control of insect pests using parasitoids may have limited success without an understanding of the effect of temperature on natural enemies. The objective was to determine the parasitism, egg viability and sex ratio of Trichogramma exiguum and Trichogramma acacioi (Hymenoptera: Trichogrammatidae) to control Heliothis virescens (Lepidoptera: Noctuidae) eggs after two generations on eggs of Anagasta kuehniella at 18, 20, 25, 30 and 33ºC. The increase in temperature favored the parasitism of T. exiguum. The egg viability of T. exiguum ranged between 70.1 and 97.1% and from 81.5 to 98.4% for T. acacioi in H. virescens eggs. The sex ratio of T. acacioi was constant at all temperatures studied, with only females in the progeny. Trichogramma exiguum reared in H. virescens eggs met the standards of quality control for mass production. Trichogramma exiguum showed higher parasitism than T. acacioi at high temperatures. However, both species had low parasitism on H. virescens eggs.

Assessing costs and benefits of pest management on forested landbases in eastern and western Canada

To assist pest management planning, the Canadian Forest Service developed the Spruce Budworm Decision Support System (SBW DSS), which quantifies the timber supply impacts of protecting stands against spruce budworm ( Choristoneura fumiferana Clem.) defoliation. We incorporated protection costs and timber product values in this system to evaluate economic aspects of spruce budworm control. The analysis allows pest managers to evaluate the degree to which the traditional volume protection priority objective corresponds to three economic criteria, namely the volume protected per dollar protection program cost, the benefit–cost ratio of the protection program, and the net present value of the protection program. Twelve alternative spruce budworm protection strategies were analyzed on Crown License 1 in New Brunswick and Prince Albert Forest Management Area (PAFMA) in Saskatchewan, based on a number of protection program extents and intensities. For both landbases under base-case market conditions, the largest, most intensive protection scenario provided the highest amount of volume saved and net present value (at 3.94 Mm 3 and $39.98 M for PAFMA, and 4.04 Mm 3 and $41.49 M for License 1, respectively) while smaller, less-intensive programs provided the highest benefit–cost ratios and volume protected per present value dollar of protection cost (at 8.22 and 0.52 m 3/$ for PAFMA, and 10.26 and 0.65 m 3/$ for License 1, respectively). Sensitivity analysis on product values and protection costs revealed that smaller, less-intensive programs could also produce the highest net present values when costs are higher and/or product values lower. These results highlight the conditions under which pest managers should consider deviating from their traditional strategy of maximizing volume saved to one that maximizes the economic returns of protection.

Modeling Spruce Budworm Population Revisited: Impact of Physiological Structure on Outbreak Control

Understanding the dynamics of spruce budworm population is very important for the protection of spruce and balsam fir trees of North American forests, and a full understanding of the dynamics requires careful consideration of the individual physiological structures that is essential for outbreak control. A model as a delay differential equation is derived from structured population system, and is validated by comparing simulation results with real data from the Green River area of New Brunswick (Canada) and with the periodic outbreaks widely observed. Analysis of the equilibrium stability and examination of the amplitudes and frequencies of periodic oscillations are conducted, and the effect of budworm control strategies such as mature population control, immature population control and predation by birds are assessed. Analysis and simulation results suggest that killing only budworm larvae might not be enough for the long-term control of the budworm population. Since the time required for development during the inactive stage (from egg to second instar caterpillar) causes periodic outbreak, a strategy of reducing budworms in the inactive stage, such as removing egg biomass, should also be implemented for successful control.

Pyrethroid Insecticide Efficacy Against Tobacco Budworm (Lepidoptera: Noctuidae) in North Carolina Flue-Cured Tobacco: Implications for Insecticide Resistance Management

Foliar applications of 3 pyrethroid insecticides were made to flue-cured tobacco and compared with Bacillus thuringiensis Berliner (Bt) bait and sprays of acephate and spinosad for control of the tobacco budworm, Heliothis virescens (F.), in 2001, 2002, and 2003. Lambda-cyhalothrin, cyfluthrin, and bifenthrin provided significant control of tobacco budworm when compared with untreated checks in all 3 yrs; however, they were generally less efficacious than the other insecticides tested. The level of control among the pyrethroids differed significantly within years but was inconsistent from year to year. The severity of tobacco budworm feeding damage was recorded for individual plants in each treatment, and damage averaged over pyrethroid treatments was 54.17% lower than the untreated control in 2001 and 79.84% lower in 2003. Pyrethroid treatments had no impact on yield of cured leaf in 2001 or 2003 compared with controls. The use of pyrethroid insecticides in flue-cured tobacco will increase the selection pressure placed on tobacco budworm populations in North Carolina. As a result, resistance to this class of insecticides may develop at an accelerated rate.

Evaluation of spray regimes of monocrotophos to control budworm (<i>Earias spp</i>.) damage to seed kenaf (<i>Hibiscus cannabinus</i> L.)<BR><BR>Evaluation des regimes d'atomisation de monocrotophes pour regler les vers du bouton (<i>Earias spp</i>.) degats causes aux graines de kenaf (Hibiscus cannabinus L.)

The effect of timing of monocrotophos application on its efficacy for the control of budworm, Earias spp . on seed kenaf was evaluated in replicated field trials at Moor Plantation, Ibadan, Nigeria. Monocrotophos was applied at the same rate, three times per season over four different kenaf growth phases and its effect (in time) on budworm attack and damages to young plant shoots, flower and capsules was noted. Results showed that spray applications initiated at 50 per cent flower set stage were as effective as those initiated at the flower bud stage for budworm control. Applications initiated at the flower bud stage gave very low per cent budworm damage (12) and larger kenaf seed yield (1,444 kg ha -1 ) as compared to the unsprayed control treatment that gave high per cent budworm damage (25) and smaller kenaf seed yield (672 kg) in the first season. The results of the second season trial followed a similar trend. Similarly, applications initiated at the 50 per cent flower set gave 11 per cent flower bud damage and seed yield of 1453 kg ha -1 compared to the unsprayed control that gave 27 per cent budworm damage yield of 690 kg ha -1 . From these results, chemical application initiated at the flower bud stage will effectively reduce budworm damage and consequently increase kenaf seed yields. Keywords : monocrotophos, budworm, Hibiscus cannabinus , spray regimes Agricultural and Food Science Journal of Ghana Vol. 3 2004: 269-277

Development and commercial use of Bollgard cotton in the USA--early promises versus today's reality.

Bollgard cotton is the trademark given to a number of varieties of cotton bio-engineered to produce an insecticidal protein from Bacillus thuringiensis (Bt). When produced by the modified cotton plants, this protein controls certain lepidopterous cotton insect pests. Commercially available since 1996, these cotton varieties are purchased under a license agreement in which the growers pay a fee and agree to abide by the terms, which include a 1-year license to use the technology and agreement to participate in an insect resistance management program. Today, Bollgard cotton is grown on more than one-third of all cotton acreage in the USA. This product has reduced cotton production costs and insecticide use by providing an effective alternative to chemical insecticides for the control of tobacco budworm, Heliothis virescens; cotton bollworm, Helicoverpa zea; and pink bollworm, Pectinophora gossypiella. The specificity and safety profile of the Bt protein produced in planta in cotton was maintained. It has retained its selectivity for lepidopterous insects and lacks the characteristics found in potential allergenic proteins. Fiber quality, the agronomic characteristics of the plant and seed composition remain unchanged. New cotton technology is being developed to provide improved insect control and a wider spectrum of activity. These future products could further reduce insecticide use in the production of cotton, while maintaining the high level of safety and reliability that has been demonstrated by five seasons of Bollgard cotton use.

Growth of Wild Pseudoplusia includens (Lepidoptera: Noctuidae) Larvae Collected from BT and Non-BT Cotton

Cotton varieties genetically engineered to express CrylAc, a delta-endotoxin protein from Bacillus thuringiensis with insecticidal properties to many Lepidopterans, are now commercially available to aid in the control of the tobacco budworm, Heliothis virescens F. (Lepidoptera: Noctuidae). Most of the resistance-management strategies for Bt cotton have focussed on this primary pest, and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), to a lesser degree. Because CrylAc is continually expressed in all tissues of the cotton plant, many Lepidopteran insects feeding on Bt cotton may experience selection pressure for improved tolerance of this insecticide. In addition to the major pests of cotton, secondary pests could also develop resistance to CrylAc when feeding on Bt cotton. Currently, there is little available information concerning the best strategy to manage resistance to CrylAc in these secondary pests (Gould and Tabashnik 1998). Soybean loopers, Pseudoplusia includens (Walker) (Lepidoptera: Noctuidae) are occasional foliage feeders of cotton and have the potential to develop resistance to CrylAc (Mascarenhas et al. 1998). We took advantage of a natural infestation of soybean loopers (SBL) in the Mississippi Delta to investigate how well SBL larvae tolerated CrylAc expressed in the leaves of Bt cotton. Comparisons were made of the numbers of larvae found in Bt and non-Bt cotton and also comparisons of the growth of larvae feeding on Bt and non-Bt cotton. We also looked at the variability in tolerances of individuals feeding on Bt cotton. Two varieties of cotton were used in this study. NuCOTN 33B (Bt cotton, treatment = 'BT') and SG125 (conventional cotton, treatment = 'NBT') were planted (9 May 1998) in a randomized design totaling 7 plots of each variety. Plot dimensions were approx. 9 x 9 m and plots were arranged in a 3 x 5 plot grid. Each plot was separated from the others by 2 m of unplanted space. On 6 July 1998, we observed a sizeable infestation of SBL larvae (first and second instars in BT and NBT treatments). Larvae from all plots were manually removed (23 July 1998), placed in plastic bags containing foliage from the plant on which each larva was feeding, and immediately brought back to the lab to be scored and weighed. The number of larvae from each plot was tabulated. Counts of larvae were log-transformed to enhance normality and to homogenize the variances in the BT and NBT treatments. A t-test was used to compare NBT and BT counts. Data are presented as untransformed average numbers per plot. In addition, larvae from 5 and 4 randomly chosen BT and NBT plots, respectively, were weighed to the nearest hundredth of a mg to look for developmental differences in SBL larvae feeding on BT and NBT foliage. Log-transformed weight (mg) data were subjected to ANOVA to determine if there were any differences in the developmental rates of larvae collected from BT and NBT plots. Bt treatment (BT vs. NBT cotton) was considered a fixed effect and plots nested within treatments [plots(treatment)] effects were considered a random source of variation (PROC GLM; SAS 1985). Satterthwaite's approximation was used to estimate the denominator degrees of freedom. Significantly more SBL larvae were collected from NBT plots than BT plots (Fig. 1; t = 3.336, df = 12, P = 0.006). Larvae from NBT plots were also significantly larger than larvae from BT plots (F = 238.96, df = 1, 104.5, P < 0.0001). The weights of larvae

YIELD OF OCCLUSION BODIES FROM SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE), LARVAE INFECTED WITH A NUCLEAR POLYHEDROSIS VIRUS

The eastern spruce budwonn, Choristoneuva fumiferana (Clem.) (Lepidoptera: Tortricidae), is subject to a variety of naturally occurring infectious diseases including nuclear polyhedrosis virus (NPV), granulosis virus (GV), cytoplasmic virus (CPV), and entomopox virus (EPV), of which the most intensively studied is NPV (CfMNPV) (Cunningham 1985). If CfMNPV is ever to be deemed an effective and economical alternative to chemical pesticides for spruce budworm control, additional research is required.

Insect Control on Flue-Cured Tobacco with Systemic Insecticides, 1996

Abstract This experiment was conducted at the Southern Piedmont Agric. Res. and Ext. Cntr., Blackstone, VA to evaluate TA and TFB control on fluecured tobacco with various systemic insecticides applied as soil or transplant water treatments and to determine the impact of these treatments on tobacco yield. Twelve treatments and an untreated check were established in a RCB design with 4 replications. Plots, 4 X 40 ft (1 row X 24 plants), were separated by single guard rows. Pre-transplant soil treatments of all liquid formulations except Furadan were broadcast with a CO2-pressurized tractor sprayer that delivered 32 gpa at 30 psi through 8003 LP tips on 3 May (Ambient temperature 74-76 °F, soil temperature, 70 °F; soil pH, 5.7; OM, &amp;lt;2%). Treatments were immediately incorporated by double disking. Band applications of Furadan and Temik were made during bed formation and immediately covered with 6 to 8 inch of soil on 8 May. Furadan 4°F band treatments were applied in a 12-inch band using a COz-pressurized backpack sprayer that delivered 16 gpa through an 8003 E tip at 30 psi. Temik was applied in a 14-inch band using a tractor mounted-Gandy granular applicator. The soil was in excellent condition for both the pre-transplant soil and bedding treatments. ‘Coker 371Gold’ fluecured tobacco was transplanted into experimental plots in a Chesterfield-Mayodan-Bourne sandy loam soil on 20 May. A measuring cup was used to apply transplant water (TPW) treatments of Orthene and Admire in 4 fl oz/plant (204 gpa) at the base of each plant in the treatment plots. Except for insect control, production practices followed Virginia Cooperative Extension recommendations. Dipel (Bacillus thuringiensis) was applied for tobacco budworm and tobacco hornworm control on 26 Jun and 8 Aug. The foliar application of Orthene were applied on 5 Jul and Aug with a CO2-pressurized backpack sprayer that delivered 28 gpa through 3 TX-12 tips at 60 psi. TA populations were estimated on the upper 4 leaves of 10 plants/plot about once a week from 5 to 9 wk after transplanting. On 25 Aug, TA damage was rated on a scale of 0 to 10: 0 = no signs of aphid damage; 10 = very severe necrosis of leaves and extensive sooty mold. TFB feeding holes were counted on 5 plants/plot at 2 and 5 wk after transplanting. Tobacco was harvested and cured and yield was determined. Data were analyzed by ANOVA and significantly different means were separated. Aphid count data were transformed to log)0 (x + 1) before analysis. Actual means are presented in the table. Admire TOW gave the best seasonlong control of TA. The Temik and Temik + Mocap GEL treatment

Tobacco Budworm and Tobacco Aphid Control on Flue-Cured Tobacco, 1996

Abstract This study was conducted at the Southern Piedmont Agric. Res. and Ext. Cntr., Blackstone, VA, to evaluate various foliar insecticides for the control of TA and TBW and for their impact on the yield of flue-cured tobacco. Tobacco ‘NC 37NF’ was transplanted into experimental plots, 8 X 40 ft (2 rows X 24 plants), on 20 May. Eight treatments and an untreated check were established in a RBC design with 4 replications. A Gandy granular applicator mounted on a tractor was used to apply Temik as a side-dress treatment to the Temik + Tracer plots on 18 Jun. Foliar treatments for TBW control were applied on 25 Jun and 19 Jul using a CO2-pressurized backpack sprayer that delivered 28 gpa at 60 psi through TX-10 nozzles (3/row). Foliar applications of Provado and Orthene in combination with Silwet 77L (4 fl oz/acre) were applied for TA control on 5 Jul and 8 Aug. Before the first application for TBW control, TBW larvae were collected from untreated fields and released at one larvae per plant on 10 plants per plot on 25 Jun and natural infestations were assessed on 10 additional plants in each plot. Before the second application for TBW, newly hatched larvae were released at 1 larva/plant on 20 plants/plot on 18 Jul. TBW were counted on 20 plants/plot at 3, 7, and 14 DAT. On 20 Aug, TBW damage was rated on a scale of 0 to 5: 0 = no damage and 5 = severe damage. TA were counted on the upper 4 leaves of 10 plants/plot. TA damage was rated on a scale of 0 to 10: 0 = no sign of TA infestations; 10 = very severe damage. The tobacco was harvested and cured and yield was determined. Data were analyzed by ANOVA and significantly different means were separated by Waller-Duncan K-ratio t-test (K - 100). TA data were transformed to log10 (x + 1) before analysis. TBW data were transformed to SQRT (X + 0.25). Actual means are presented in the table.

Aphid Control on the Flue-Cured Tobacco with Foliar Insecticides, 1997

Abstract This experiment was conducted at the Southern Piedmont Agric. Res. and Ext. Cntr., Blackstone, VA to evaluate various foliar insecticides for TA control and to determine the effects of the treatments on the yield of flue-cured tobacco. Tobacco ‘Coker 371Gold’ was transplanted into experimental plots on 19 May. Seven treatments and an un-treated control was established in a RCB design with 4 replications. Plots, 4 X 40 ft (1 row X 24 plants), were separated by a single untreated guard rows. Except for insect control, flue-cured tobacco production methods followed the recommendations of the Virginia Cooperative Extension Service. Treatments were applied as foliar sprays with a CO2-pressurized backpack sprayer that delivered 30 gpa at 50 psi through TX-12 nozzles (3/row) on 4 and 22 Jul. Temperatures ranged from 88-90 °F during both applications. TA counts were made on the upper 4 leaves of 10 plants per plot before treatment and at 3 to 24 DAT. On 21 Aug, TA damage was rated on a scale of 0-10: 0 = no injury; 10 = very severe injury as indicated by necrotic leaf tissue, honey-dew, and sooty mold. Dipel 4 L at 0.5 qt/acre was applied to the entire test for budworm and tobacco hornworm control on 3 Jul. Tobacco was harvested, cured and yield was determined. Data were analyzed by ANOVA and significantly different means were separated by Waller-Duncan K-ratio t-test (K = 100). TA count data were transformed to log10 (x + 1) before analysis. Actual means are presented in the table.

Insect Control of Flue-Cured Tobacco with Systemic Insecticides, 1997

Abstract This experiment was conducted at the Southern Piedmont Agric. Res. and Ext. Cntr., Blackstone, VA to evaluate TA and TFB control on flue-cured tobacco with various systemic insecticides applied as soil or transplant water treatments and to determine the impact of these treatments on tobacco yield. Thirteen treatments and an untreated check were established in a RCB design with 4 replications in a Chesterfield-Mayodan-Bourne sandy loam soil. Plots, 4 X 40 ft (1 row X 24 plants), were separately by single guard rows. Pre-transplant soil treatments of all liquid formulations except Furadan were broadcast with a CO2-pressurized tractor sprayer that delivered 32 gpa at 30 psi through 8003 LP tips on 13 May (Ambient temperature 66-68 °F, soil temperature, 65 °F; soil pH, 5.7; OM, &amp;lt;2%). Treatments were immediately incorporated by double disking. Band applications of Furadan and Temik were made during bed formation and immediately covered with 6 to 8 inch of soil on 15 May (Ambient temperature 75-78 °F, soil temperature, 70 °F). Furadan 4°F band treatments were applied in a 12-inch band using a CO2-pressurized backpack sprayer that delivered 16 gpa through an 8003E tip at 30 psi. Temik was applied in a 14-inch band using a tractor mounted-Gandy granular applicator. The soil was in excellent condition for both the pretransplant soil and bedding treatments. ‘Coker 371Gold’ flue-cured tobacco was transplanted into experimental plots on 19 May. A measuring cup was used to apply transplant water (TPW) treatments of Orthene and Admire in 4 fl oz/plant (204 gpa) at the base of each plant in the treatment plots. Except for insect control, production practices followed Virginia Cooperative Extension recommendations. Dipel (Bacillus thuringiensis) was applied for tobacco budworm and tobacco hornworm control on 3 Jul. Foliar applications of Orthene were applied to the Orthene TPW treatment on 5 and 31 Jul and to the Furadan treatment on 19 Jul using a CO2-pressurized back-pack sprayer that delivered 30 gpa through TX-12 tips (3 per row) at 50 psi. TA populations were estimated on the upper 4 levels of 10 plants/plot every 6 to 12 days from late Jun to mid Aug. On 25 Aug, TA damage was rated on a scale of 0 to 10: 0 = no signs of damage; 10 = very severe necrosis of leaves and extensive sooty mold. TFB and TFB feeding holes were counted on 10 plants/plot at 1 to 4 wks after transplanting. Tobacco was harvested as it ripened, weighted, and yield was calculated. Data were analyzed by ANOVA and significantly different means were separated by Waller-Duncan K-ratio t-test (K = 100). TA count data were transformed to log10 (x + 1) before analysis. Actual means are presented in the table.

Bollworm and Tobacco Budworm Control with Selected Insecticides, 1997

Abstract A small-plot trial was conducted at the Red River Research Station, Bossier City, LA, to determine the efficacy of selected insecticides in controlling the bollworm/tobacco budworm (BW/TBW) complex on cotton. The experimental design was a RCB with 4 replications. Plots were planted 9 May and were 4 rows X 100 ft on 40-inch centers. All plots had Temik 15 G (0.5 lb [AI]/acre) applied in-furrow at planting. Prior to trial initiation, plots were oversprayed for cutworms on 6 Jun (Karate 1 EC at 0.025 lb [AI]/acre); boll weevils on 9, 13, 18 Jun and 3 Jul (Vydate C-LV at 0.25 lb [AI]/acre); BW/TBW on 27 Jun (Baythroid 2 EC at 0.03 lb |AI]/acre), and 11 Jul (Karate 1 EC at 0.03 lb [AI]/acre); and for aphids on 17 Jul (Provado 1.6°F at 0.047 lb [AI]/acre). Insecticide test materials were applied on 14, 21, 28 Jul, 5 and 14 Aug in 5.9 gal total spray solution/acre at 60 psi with TX-3 hollow-cone nozzles spaced 20 inches apart (2 noz-zles/row). Treatments were applied with a high-clearance sprayer equipped with a CO2 system for spraying small plots. Infestations of BW/TBW larvae and square damage were monitored on 17, 24, 31 Jul, and 7 Aug by examining 25 squares/plot. Following the trial, all plots were oversprayed for BW/TBW on 22 Aug with Karate 1 EC plus Curacron 8 EC at 0.028 + 0.75 lb [AI]/acre. Boll weevil eradication sprays with weekly applications of ULV Malathion (12 oz product/acre) were begun the week of 18 Aug. Yields were determined by mechanically harvesting the center 2 rows of each plot on 7 Oct.

Efficacy of Selected Insecticide Mixtures for Bollworm and Tobacco Budworm Control, 1997

Abstract Thirteen treatments were evaluated at the Red River Research Station, Bossier City, LA, to determine their efficacy in controlling the bollworm/tobacco budworm (BW/TBW) complex on cotton. Plots were planted 9 May and were 4 rows X 100 ft on 40-inch centers. All plots had Temik 15 G (0.5 lb (AI)/acre) applied in-furrow at planting. The experimental design was a RCB with 4 replications. Prior to trial initiation, plots were oversprayed for cutworms on 6 Jun (Karate 1 EC at 0.025 lb (AI)/acre); boll weevils on 9, 13, 18 Jun and 3 Jul (Vydate C-LV at 0.25 lb (AI)/acre); BW/TBW on 27 Jun (Baythroid 2 EC at 0.03 lb (AI)/acre), and 11 Jul (Karate 1 EC at 0.03 lb (AI)/acre); and for aphids on 17 Jul (Provado 1.6°F at 0.047 lb (AI)/acre). Test materials were applied with a high-clearance sprayer equipped with a CO2 system for spraying small plots. Insecticide treatments were applied on 15, 22, 29 Jul, 5 and 14 Aug in 5.9 gpa at 60 psi with TX-3 hollow-cone nozzles spaced 20 inches apart (2 nozzles/row). Infestations of BW and TBW larvae and square damage were monitored on 18, 25 Jul, 1 and 11 Aug by examining 25 squares/plot. Following the trial, all plots were oversprayed for BW/TBW on 22 Aug with Karate 1 EC plus Curacron 8 EC at 0.028 + 0.75 lb (AI)/acre. Boll weevil eradication sprays with weekly applications of ULV Malathion (12 oz product/acre) were begun the week of 18 Aug. Yields were determined by mechanically harvesting the center 2 rows of each plot on 7 Oct.

Resistance of Cotton with δ‐Endotoxin Genes from Bacillus thuringiensis var. kurstaki on Selected Lepidopteran Insects

AbstractTransgenic cotton (Gossypium hirsutum L.) plants that express truncated versions of insect control protein genes cryIA (c) and cryIIA of Bacillus thuringiensis Berliner var. kurstaki (Bt) have been developed for managing lepidopteran pests. However, agronomic traits and pest resistance can vary among transformation events. We examined selected agronomic traits and resistance, in laboratory and field, against tobacco budworm [Heliothis virescens (F.)] and bollworm [Helicoverpa zea (Boddie)] for various transformation events of the cryIA(c) and cryIIA genes. Monsanto events with cryIIA were as resistant to tobacco budworm and bollworm as the M531 Bt event of cryIA(c), but showed some yield loss. Calgene events ST 807, ST 808, and ST 317 expressing cryIA(c) were similar to the M531 Bt event of cryIA(c) in control of tobacco budworm and bollworm. Backcrossed cultivars NuCOTN 33B and NuCOTN 35B from Delta &amp; Pine Land Co. with event M531 Bt of cryIA(c) were highly resistant to tobacco budworm, producing more than 1400 kg ha−1 (vs. 0 on nontransgenic recurrent parents) under high levels of tobacco budworm infestation. These NuCOTN cultivars also yielded 450 to 550 kg ha−1 more lint than the recurrent parents under high levels of natural infestation of tobacco budworm in the insecticide control treatment; in the absence of tobacco budworm, NuCOTN yields were equal to or greater than for recurrent parents. The Paymaster Technologies lines with event M757 Bt of cryIA(c) were not pure for the gene, but showed excellent field resistance to tobacco budworm. Lines HX2 BG and HX3 BG showed resistance equal to the donor event M757 and yields equal to H1244. Reduced performance of event M757 in HX6 BG relative to other Paymaster lines with this event indicates a significant genotype × event interaction. Laboratory survival of bollworm after 7 d on transgenic leaves and squares was greater than survival of tobacco budworm; however, weight of surviving larvae of each species was only 10 to 15% of that on nontransgenic controls. Survival of fall armyworm [Spodoptera frugiperda (J.E. Smith)] at 7 d was only slightly lower than on nontransgenics, and weights were slightly lower. Careful evaluation of transgenic events and cultivars is necessary to ensure that the final cultivar is both resistant to target pests and has acceptable yield.

Dissipation kinetics of azadirachtin in some forest matrices and its systemic translocation in conifers for spruce budworm control

Field microcosm studies were conducted to investigate the deposition, persistence, translocation and bioactivity of the botanical insecticide azadirachtin‐A (AZ‐A) in young spruce trees. The deposition and persistence of AZ‐A in aspen foliage, forest soil and litter were also studied. AZ‐A residues in the different matrices were monitored at intervals of time after spray application of Neemix® 4.5 formulation at 100 g AZ‐A in 2.3 L/ha. The dissipation half‐lives in the matrices ranged from 16.9 to 33.6 h. AZ‐A was translocated and concentrated in the growing parts (especially the shoots) of spruce trees, after treatment by trunk injection (Tl), basal bark painting (BBP) and foliar painting (FP) of the Neemix 4.5 formulation. Systemically translocated and accumulated AZ‐A residues in the shoots after Tl and FP were found to be effective against spruce budworm (Choristoneura fumiferana Clemens.) larvae. Results suggest that Tl may be a useful way of using neem insecticide to protect high value trees from insect pests.