Response of Mexican Corn Rootworm to Insecticides, 1991

Abstract Populations of MCR of commercial field corn from Arenal, Jalisco were exposed to nine insecticides of organophosphorous (OP), cabamate, organo chlorinated and pyrethroid groups. Larvae were collected from the roots of corn plants daily, and confined in polyethylene black bags of two kg capacity with humidity and germinated corn as food for larvae. Insects were taken to the laboratory of Sanidad Vegetal in Guadalajara, Jalisco. Dilutions of the insecticides tested were prepared using acetone from 500 to 5000 ppm (6 to 9 dosage/product). For this study 20 larvae of last instar were selected and 1 u, liter of the solution was placed topically on the thorax, after this, each larva was placed in a petri dish with a moistened paper towel and the petri dishes confined in a cardboard box to eliminate light. Mortality counts were carried out at 24 hours. Percent mortality was corrected by Abbott’s formula. The mortality data were analyzed by probit to obtain LC50 and LC,5 values for each insecticide.

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EVALUATION OF AN OVIPOSITION TRAP FOR MONITORING EGG POPULATIONS OF DIABROTICA SPP. (COLEOPTERA: CHRYSOMELIDAE) IN FIELD CORN

The Canadian Entomologist ◽

10.4039/ent127839-6 ◽

1995 ◽

Vol 127 (6) ◽

pp. 839-849 ◽

Cited By ~ 3

Author(s):

Barbara S. Mulock ◽

Cliff R. Ellis ◽

Gary H. Whitfield

Keyword(s):

Water Saturation ◽

Aggregate Size ◽

Economic Damage ◽

Metal Ring ◽

Corn Rootworm ◽

Field Corn ◽

Corn Plants ◽

Clay Aggregates ◽

Oviposition Sites ◽

Oviposition Trap

AbstractTraps consisting of open, cylindrical tins containing moistened clay aggregates were evaluated as field oviposition sites for corn rootworm, Diabrotica spp. Six trap features were investigated: clay aggregate size, water saturation level, trap opening, trap cover, trap volume, and trap position relative to corn plants. More eggs were recovered in traps containing clay aggregates ranging from 0.5 to 3.5 mm diameter compared with aggregates from 2.5 to 8.0 mm diameter. Saturation of the trap to 2.5 cm from the opening resulted in greater egg recovery compared with traps saturated to 6.0 cm from the opening. Covering the exposed surface of the trap with a metal ring and/or a corn leaf increased egg recovery in the field.Oviposition traps were placed in four commercial corn fields in 1990 and three in 1991 to monitor egg populations. Egg recovery from traps and estimates of the absolute egg population in the soil were compared with densities of adult corn rootworm to predict larval damage on roots of corn planted the next year. In five fields, adult populations were above the current economic threshold of one beetle per plant. However, economic damage to roots occurred only in the field in which the most eggs were recovered from traps (226.6 eggs per trap) and soil samples (30.2 eggs per litre). Mean egg recovery per trap per field was correlated with mean damage ratings from untreated corn.

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Control of Western Corn Rootworm Larvae in West Central Nebraska, 1992

Arthropod Management Tests ◽

10.1093/amt/19.1.209 ◽

1994 ◽

Vol 19 (1) ◽

pp. 209-209

Author(s):

R. C. Seymour ◽

J. B. Campbell ◽

R. J. Wright

Keyword(s):

Growth Stage ◽

Rating Scale ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Root Damage ◽

Time Of Application ◽

Field Corn ◽

West Central ◽

The Press ◽

Corn Plants

Abstract Granular insecticides were applied to suppress larval rootworm populations in 2 fields in west central NE. ‘Pioneer 3394’ hybrid field corn was ridge-planted in Field 1 with a John Deere Max-emerge planter, to a non-tilled seed bed on 11 May. Insecticides were applied at planting with insecticide boxes attached to the planter. Three replications of each treatment were arranged in a RCB design. T-band applications were made by applying a 7 inch band of insecticide in front of the press wheel. In-furrow applications were made by applying insecticide directly into the seed furrow. All insecticides were applied at a rate of 1114.5 g (AI)/ha. Field 2 was ridge-planted to ‘Fontanelle 4435’ and ‘Fontanelle 6240’ hybrid field corn with a John Deere Max-emerge planter, to a non-tilled seed bed on 6 May. With the exception of 4 strips, 12 rows in width, Counter 15G was applied at planting with insecticide boxes on the planter at a rate of 1114.5 g (AI)/ha. A granular and a liquid insecticide were applied to untreated strips in Field 2 immediately prior to cultivation on 15 Jun. The field corn plants were in the early whorl stage (growth stage 2) of development at the time of application. The granular application was applied over the whorl of the plants with insecticide boxes attached to a tool bar. The liquid insecticide was applied in a 7 inch band to the base of the plants in total volume of 120 liter/ha at 206,786 Pa (30 psi). Cultivation treatments were applied at a rate of 1114.5 g (AI)/ha. Each treatment in Field 2 was applied to 10 × 4 m plots which were replicated 4 times and arranged in a RCB design. Two blocks of treatments were applied to ‘Fontanelle 4435’ hybrid field corn plants and 2 blocks of treatments were planted to ‘Fontanelle 6240’ hybrid field corn plants. Treatments in both fields were evaluated 13 Jul by rating washed roots, using the 1-6 Iowa Root Damage Rating Scale, of 4 plants from each replicate.

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Persistence of Foliar-Applied Insecticides for Elm Leaf Beetle Control, Trial Two, 1995

Arthropod Management Tests ◽

10.1093/amt/21.1.370 ◽

1996 ◽

Vol 21 (1) ◽

pp. 370-371

Author(s):

D. Casey Sclar ◽

Whitney S. Cranshaw

Keyword(s):

Petri Dish ◽

Leaf Beetle ◽

Time Interval ◽

Elm Leaf Beetle ◽

Run Off ◽

Percent Mortality ◽

Petri Dishes ◽

Mortality Estimates

Abstract The mortality of elm leaf beetle larvae to foliar-applied insecticides sprayed on different dates was assessed. Three different insecticides were examined for differences in performance. Siberian elm foliage was treated with foliar-applied insecticides on each of 4 different dates. Treatments were applied with a pump-mister sprayer to the point of run-off. All foliage was collected and bagged on 24 Jul. In the laboratory, 10 larvae were placed in a petri dish and treated foliage was introduced for consumption. Mortality was assessed at 48 and 96 h after exposure by counting the number of dead, live, moribund and pupated larvae present in a petri dish at a given time interval. A few larvae in the petri dishes became infected with the fungus Beauvaria bassiana (Balsamo) Vuillemin and subsequently died during the course of the experiment. For this reason, only dead, uninfected larvae were used to calculate percent mortality estimates. The experiment was analyzed as a CRD with 8 replications per treatment.

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Distribution of Fall Armyworm Larvae. 1. Regions of Field Corn Plants Infested by Larvae 1

Environmental Entomology ◽

10.1093/ee/2.2.195 ◽

1973 ◽

Vol 2 (2) ◽

pp. 195-198 ◽

Cited By ~ 8

Author(s):

Wendell L. Morrill ◽

G. L. Greene

Keyword(s):

Fall Armyworm ◽

Field Corn ◽

Corn Plants

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EFFECT OF SPACING AND CLUMPING OF CORN PLANTS ON DENSITY OF CORN-ROOTWORM LARVAE (COLEOPTERA: CHRYSOMELIDAE) PER ROOT SYSTEM

The Canadian Entomologist ◽

10.4039/ent117139-2 ◽

1985 ◽

Vol 117 (2) ◽

pp. 139-142 ◽

Cited By ~ 1

Author(s):

Olga Piedrahita ◽

C. R. Ellis ◽

O. B. Allen

Keyword(s):

Relative Density ◽

Root System ◽

Corn Rootworm ◽

Plant Spacing ◽

Corn Rootworms ◽

Corn Plants ◽

The Relationship ◽

Field Plots

AbstractThe relative density of corn-rootworm larvae was estimated in two field plots with 4 different plant spacings and with up to 4 plants clumped per location. In both fields the relationship between plant spacing and the number of corn rootworms per sample was similar with the maximum number of larvae occurring when plants were 46 or 50 cm apart. The number of plants clumped per location affected the numbers of corn rootworm in only one field. The relationship between clumping of plants and number of corn rootworms was curvilinear in this field with the most corn rootworms occurring at 3 plants per location.

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Laboratory Bioassay of Beauveria Bassiana, Spinosad, Garlic, and Neem-Derived Products for Control of Grasshoppers

Arthropod Management Tests ◽

10.1093/amt/23.1.372 ◽

1998 ◽

Vol 23 (1) ◽

pp. 372-372

Author(s):

Nihat Demirel ◽

Whitney Cranshaw

Keyword(s):

Beauveria Bassiana ◽

Petri Dish ◽

Neem Oil ◽

Laboratory Bioassay ◽

Neem Extract ◽

Late Instar ◽

Petri Dishes

Abstract Trials were conducted with adult, field collected migratory grasshoppers to determine susceptibility to ingestion expo sure to Beauveria bassiana Strain GHA (BotaniGard WP), spinosad (Conserve SC) a garlic-derived insecticide/repellent (Garlic Barrier), neem oil (Tril ogy) and a neem extract (BioNeem). Field collected late instar grasshoppers were confined, 8 per petri dish (100 mm X 15 mm), with 6 petri dishes usetl per treatment. Treatments involved dipping alfalfa leaves into the insecticide solutions and allowing them to air dry before feeding these to the grasshop pers. After the originally treated foliage were consumed, untreated foliage was used to maintain grasshoppers in all treatments. Mortality was assessed a 24, 48, 96, and 192 h after exposure.

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Insect-Mediated Dispersal of the Rhizobacterium Pseudomonas chlororaphis

Phytopathology ◽

10.1094/phyto.1998.88.12.1248 ◽

1998 ◽

Vol 88 (12) ◽

pp. 1248-1254 ◽

Cited By ~ 10

Author(s):

William E. Snyder ◽

David W. Tonkyn ◽

Daniel A. Kluepfel

Keyword(s):

Escherichia Coli ◽

Adult Stage ◽

Genetically Modified ◽

Insect Pest ◽

Corn Rootworm ◽

Transmission Route ◽

Pseudomonas Chlororaphis ◽

Naturally Occurring ◽

Southern Corn Rootworm ◽

Corn Plants

The southern corn rootworm, Diabrotica undecimpunctata subsp. howardi, a common and mobile insect pest, was shown to transmit the rhizobacte-rium Pseudomonas chlororaphis strain L11 between corn plants. Strain L11 has been genetically modified to contain the lacZY genes from Escherichia coli. It can reach high densities on roots and invade the roots and move into the foliage. D. undecimpunctata subsp. howardi became infested with L11 as larvae while feeding on roots of seed-inoculated corn and retained the bacteria through pupation, molting to the adult stage, and emergence from the soil. Bacterial densities on or in the insects increased 100-fold after they fed again as adults on L11-infested foliage. Adults retained the bacteria for at least 2 weeks after last exposure and could transmit L11 to new plants. The likelihood of transmission decreased with time since last exposure to L11, but increased with time spent on the new plants. This research demonstrates that rhizobacteria can escape the rhizosphere by moving in or onto foliage, where they can then be acquired and transmitted by insects. This transmission route may be common among naturally occurring rhizobacteria and facilitate the dispersal of both beneficial and harmful soilborne microorganisms.

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Bioassay, Laboratory Tests of Beauveria Bassiana, Bacillus Thuringiensis, and a Feeding Stimulant on Leafroller Larvae, 1994

Arthropod Management Tests ◽

10.1093/amt/20.1.349 ◽

1995 ◽

Vol 20 (1) ◽

pp. 349-349

Author(s):

J. F. Brunner ◽

M. D. Doerr ◽

L. O. Smith

Keyword(s):

Beauveria Bassiana ◽

Petri Dish ◽

Larval Survival ◽

Wetting Agent ◽

Food Storage ◽

Storage Container ◽

Feeding Stimulant ◽

Petri Dishes ◽

Extension Center ◽

Leaf Disks

Abstract Beauveria bassiana (Naturalis-L), two B. thuringiensis products (Dipel and Troy Bt), and a feeding stimulant (Konsume) combined with a B. thuringiensis product were evaluated using a leaf-dip bioassay method for their effect on PLR and OBLR larvae. Treatments were prepared by diluting the appropriate amt of product (see table) in 500 ml water in a glass beaker. The Konsume treatments received a constant 1X rate of Dipel and 4X-0.25X rates of Konsume. A small amt (about 2 ml) of wetting agent, X-77®, was added to each treatment. An untreated control was prepared using water plus the wetting agent only. Untreated apple leaves were collected from ‘Red Delicious’ trees at the WSU Tree Fruit Research and Extension Center, Wenatchee. Leaves were dipped, then allowed to dry. Two punches (2.3 cm diameter) were taken from each leaf. Four punches were placed in a petri dish (Falcon 1006, 50 × 9 mm). Petri dishes were chosen randomly, and five 1- to 2-d-old leafroller larvae were placed on the leaf disks. The petri dish lid was put in place and dishes were placed inside a food storage container and kept at 75°F (± 2°F) constant temperature and a photoperiod of 16:8 (L:D) h. Petri dishes were examined after 7 d and larval survival recorded. Ten dishes were used for each treatment (50 larvae per treatment).

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Apple, Insecticide DIP Test (Tabm vs. Insecticides), 1993

Arthropod Management Tests ◽

10.1093/amt/19.1.369 ◽

1994 ◽

Vol 19 (1) ◽

pp. 369-369

Author(s):

R. L. Horsburgh ◽

J. R. Warren

Keyword(s):

Filter Paper ◽

Room Temperature ◽

Petri Dish ◽

Spray Application ◽

Water Control ◽

Poor Control ◽

Laboratory Bioassay ◽

The Third ◽

Petri Dishes ◽

Dip Test

Abstract A large commercial apple grower reported failure in attempts to control TABM with airblast applications of Penncap M (2 pt/acre) combined with methomyl (3 pt/acre). At the time of the grower applications larval hatch had begun and most larvae were in the first or second instar. By the time larvae were entering the third instar (10 days after spray application) it was apparent that commercially acceptable control had not been achieved. In 1992 this grower also had poor control when Penncap M was applied to suppress redbanded leafroller and experiments showed that tolerance of Penncap M was present in the resident RBLR population (Horsburgh et al. 1992). This laboratory bioassay was begun on 3 Sep to determine tolerance of the TABM population to Penncap M and other insecticides. Seven treatments (including a water control) were selected and rates calculated on the basis of 300 gal of spray being applied per acre. The appropriate dosage of pesticide for each treatment was mixed with 1 gallon of 77°F water in clean 1 gallon battery jars. Twenty plastic petri dishes containing moistened filter paper were prepared and served as individual cages for twenty 3rd instars per treatment. The larvae, on single leaves, were immersed in the appropriate solutions for five seconds and the leaf placed on the moist filter paper. The petri dish cover was put in place and the cages held at room temperature (80°F) for the duration of the test. All larvae were examined at 24 hour intervals and mortality was recorded. Death of larvae was assumed when no movement was observed when the larvae were gently prodded with a blunt steel probe.

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Effect of AC 263,222, Imazethapyr, and Nicosulfuron on Weed Control and Imidazolinone-Tolerant Corn (Zea mays) Yield

Weed Technology ◽

10.1017/s0890037x00040860 ◽

1996 ◽

Vol 10 (4) ◽

pp. 822-827 ◽

Cited By ~ 9

Author(s):

C. Dale Monks ◽

John W. Wilcut ◽

John S. Richburg ◽

Joseph H. Hatton ◽

Michael G. Patterson

Keyword(s):

Zea Mays ◽

Weed Control ◽

Application Rate ◽

Field Corn ◽

Pitted Morningglory ◽

Dry Conditions ◽

Ac 263,222 ◽

Imidazolinone Herbicides ◽

Commercial Field

Imidazolinone herbicides injure currently available commercial field corn cultivars; however, cultivars resistant to these herbicides have been developed. Sicklepod, Texas panicum, and annual morningglory control using AC 263,222 (36 and 72 g ai/ha), imazethapyr (36 and 72 g ai/ha), or nicosulfuron (35 g ai/ha) applied POST at 2,4, and 6 wk after planting were evaluated in imidazolinone-tolerant corn. Studies were conducted at Attapulgus and Plains, Georgia from 1992 through 1993. Nicosulfuron and AC 263,222 at 72 g/ha controlled Texas panicum at least 87% when applied 2 wk after planting. Imazethapyr did not consistently control Texas panicum or sicklepod, regardless of application rate. AC 263,222 at both rates and nicosulfuron controlled sicklepod at least 86% when applied 2 wk after planting; however, later application or application under dry conditions generally resulted in reduced control. All herbicides controlled the entireleaf and pitted morningglory complex at least 84% when applied 2 wk after planting. Imidazolinone-tolerant corn was tolerant to all herbicides, regardless of rate and timing, and generally yielded greater when weeds were controlled early in the season.

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