Insect-Mediated Dispersal of the Rhizobacterium Pseudomonas chlororaphis

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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Evaluation of the Peanut Southern Corn Rootworm Advisory

Peanut Science ◽

10.3146/pnut.31.1.0006 ◽

2004 ◽

Vol 31 (1) ◽

pp. 28-32 ◽

Cited By ~ 5

Author(s):

D. A. Herbert ◽

S. Malone ◽

R. L. Brandenburg ◽

B. M. Royals

Keyword(s):

North Carolina ◽

High Risk ◽

Case Studies ◽

Insect Pest ◽

Low Risk ◽

Corn Rootworm ◽

Moderate Risk ◽

Insecticide Treatment ◽

Field Case ◽

Southern Corn Rootworm

Abstract The southern corn rootworm, Diabrotica undecimpunctata howardi Barber, is an annual soil insect pest of peanut (Arachis hypogaea L.) in Virginia, North Carolina, Texas, and other peanut growing states. Larvae feed on developing pods causing direct yield loss and indirect damage by allowing entry of secondary pathogens. Because southern corn rootworm is a soil pest, scouting is difficult and producers make preventive treatments without knowledge of actual pest abundance. A predictive index for southern corn rootworm injury was evaluated using 392 field case studies conducted in Virginia and North Carolina from 1997 to 2001. Factors influencing the index score (soil texture, soil drainage class, planting date, cultivar resistance, and field history of rootworm damage), and point assignments for predicting low, moderate, and high-risk fields were analyzed. The goal of this project was to determine which combination of factors provided the highest percentage of correct risk predictions. The best index combination used all five factors to determine the total point score, with 70 or more points indicating a high-risk field, 55 to 65 points a moderate-risk field, and less than or equal to 50 points a low-risk field. Growers who use the index eliminate a preventive insecticide treatment in low-risk and some moderate-risk fields. The index correctly predicted the level of pod damage in 45% (177 of 392) of the field case studies. Insecticide was correctly recommended in 46 fields. Thirty-three percent (131 of 392) of the fields were correctly identified as not needing treatment. There were 209 cases where there was an overestimation of pod damage with predictions of either a high or moderate level when only a low level occurred. In these cases, an insecticide treatment would have been recommended and an average of 6.1 and 2.6% pod damage, respectively, would have been prevented. Conversely, there were very few fields that should have been treated but were not treated (6 of 392). Overall, use of the index would have protected fields from pod damage and potential loss 98.5% of the time.

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Evaluation of a Water-Soluble Bait for Corn Rootworm (Coleoptera: Chrysomelidae) Control2

Journal of Entomological Science ◽

10.18474/0749-8004-33.4.355 ◽

1998 ◽

Vol 33 (4) ◽

pp. 355-364 ◽

Cited By ~ 5

Author(s):

Robert F. W. Schroder ◽

Albert B. DeMilo ◽

Chang-Joo Lee ◽

Phyllis A. W. Martin

Keyword(s):

Adult Mortality ◽

Water Soluble ◽

Corn Rootworm ◽

Field Cage ◽

Feeding Stimulant ◽

Diabrotica Undecimpunctata Howardi ◽

Southern Corn Rootworm ◽

Lethal Time ◽

Corn Plants ◽

Red Dye

Laboratory and field-cage experiments evaluated the efficacy of a water-soluble bait for control of adult diabroticites. The bait was composed of a water-soluble feeding stimulant derived from a bitter mutant of Hawkesbury watermelon (Citrullus vulgaris Schrad), a dye toxin (phloxine B: D & C Red Dye No. 28), and a modified food starch (Mira Sperse 626). In the laboratory, southern corn rootworm, Diabrotica undecimpunctata howardi Barber adults, were exposed to separate bait components and combinations thereof. Eighty percent of adults exposed to the complete bait formulation died within 24 h. Adult mortality increased with higher concentrations of dye and increasing light intensity. Incorporation of the feeding stimulant with the dye reduced the lethal time. The complete bait was most active in sunlight, killing 90% adults in 1 h. Under fluorescent lights, the LT90 for the adults was 48 h. In field cages, using corn plants treated with the bait formulation, numbers of live western corn rootworm, D. virgifera virgifera LeConte, adults were reduced by 80% compared with the untreated control. This new water soluble toxic bait appears suitable for testing on a larger scale in the field as a component of an IPM program for corn rootworm pests.

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Response of Mexican Corn Rootworm to Insecticides, 1991

Arthropod Management Tests ◽

10.1093/amt/20.1.329 ◽

1995 ◽

Vol 20 (1) ◽

pp. 329-329

Author(s):

E. Guerrero-Rodriguez ◽

S. Davalos-Luna ◽

J. Corrales-Reynaga

Keyword(s):

Petri Dish ◽

Mortality Data ◽

Corn Rootworm ◽

Field Corn ◽

Paper Towel ◽

Percent Mortality ◽

Petri Dishes ◽

Mexican Corn Rootworm ◽

Corn Plants ◽

Commercial Field

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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Biosensor studies of collagen and laminin binding with immobilized Escherichia coli O157:H7 and inhibition with naturally occurring food additives

10.1117/12.335769 ◽

1999 ◽

Cited By ~ 3

Author(s):

Marjorie B. Medina

Keyword(s):

Escherichia Coli ◽

Food Additives ◽

Escherichia Coli O157 ◽

Naturally Occurring ◽

Laminin Binding

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SOS induction of selected naturally occurring substances in Escherichia coli (SOS chromotest)

Mutation Research/Genetic Toxicology and Environmental Mutagenesis ◽

10.1016/s1383-5718(99)00141-2 ◽

1999 ◽

Vol 445 (1) ◽

pp. 81-91 ◽

Cited By ~ 98

Author(s):

Sebastian Kevekordes ◽

Volker Mersch-Sundermann ◽

Christian M Burghaus ◽

Jan Spielberger ◽

Heinz H Schmeiser ◽

...

Keyword(s):

Escherichia Coli ◽

Sos Induction ◽

Naturally Occurring ◽

Sos Chromotest

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Myco-Biocontrol of Insect Pests: Factors Involved, Mechanism, and Regulation

Journal of Pathogens ◽

10.1155/2012/126819 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 44

Author(s):

Sardul Singh Sandhu ◽

Anil K. Sharma ◽

Vikas Beniwal ◽

Gunjan Goel ◽

Priya Batra ◽

...

Keyword(s):

Biological Control ◽

Recent Progress ◽

Insect Pests ◽

Insect Pest ◽

Past Research ◽

Attractive Alternative ◽

Insect Pest Control ◽

Naturally Occurring ◽

Chemical Inputs ◽

Chemical Pesticides

The growing demand for reducing chemical inputs in agriculture and increased resistance to insecticides have provided great impetus to the development of alternative forms of insect-pest control. Myco-biocontrol offers an attractive alternative to the use of chemical pesticides. Myco-biocontrol agents are naturally occurring organisms which are perceived as less damaging to the environment. Their mode of action appears little complex which makes it highly unlikely that resistance could be developed to a biopesticide. Past research has shown some promise of the use of fungi as a selective pesticide. The current paper updates us about the recent progress in the field of myco-biocontrol of insect pests and their possible mechanism of action to further enhance our understanding about the biological control of insect pests.

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A Risk Index for Determining Insecticide Treatment for Southern Corn Rootworm in Peanut

Peanut Science ◽

10.3146/i0095-3679-24-2-14 ◽

1997 ◽

Vol 24 (2) ◽

pp. 128-134 ◽

Cited By ~ 5

Author(s):

D. A. Herbert ◽

W. J. Petka ◽

R. L. Brandenburg

Keyword(s):

North Carolina ◽

South Carolina ◽

Risk Index ◽

Production Costs ◽

Corn Rootworm ◽

Price Support ◽

Insecticide Treatment ◽

Field Case ◽

Southern Corn Rootworm ◽

The Individual

Abstract The southern corn rootworm, Diabrotica undecimpunctata howardi Barber, is a primary pest of peanut, Arachis hypogaea L., in Virginia and North Carolina and an occasional pest in South Carolina, Georgia, Alabama, and Texas. Currently, no alternatives involving integrated pest management exist for this pest, and control is based solely on preventive application of soil insecticides. Recent reductions in federal price support for peanut grown in the U.S. have provided incentives for growers to look for ways to reduce production costs. A risk index was developed that integrates factors that influence rootworm abundance and peanut pod damage to estimate levels of risk in individual peanut fields, and thus allows for more prescriptive and economical rootworm management. This index was evaluated using 44 field case studies in Virginia and North Carolina commercial peanut fields over the period 1989 to 1996. In each field case, predicted risk was compared to actual percent pod damage. Results showed that in 29 of 44 cases, the index accurately predicted general levels of risk to pod damage, and insecticide treatment decisions based on the index would have been correct in 32 of 44 cases. This report contains the individual index components, the justification for each, the indexing process, example index scenarios, and results of the process used in field case study evaluation.

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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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